Ms-Access Advanced VBA Programming Techniques, Tips and Tricks.

Activity Dates and Quarterly Reports

There are four Quarters in a Year:

Jan - Mar = 1st Quarter
Apr - Jun = 2nd
Jul - Sep = 3rd
Oct - Dec = 4th

First three months of the year is first quarter, next three months belongs to second Quarter and so on.

Usually, when we prepare a Quarterly Report (for a period of three months based on the table above) we use date-range value to filter the required data for the report.

For example: To prepare Sales Report for the Second Quarter of Sales Year 2017 we will set the date range from April 1st, 2017 to June 30, 2017 as data filtering criteria in a SELECT Query. Probably we may use a Date-Picker control on the parameter entry Form to make it easier to pick and set the date values, rather than typing the date range manually.

If the Report preparation procedure is created on the above fixed pattern then the task can be made easier by creating a small Function and use it on the data filtering Query

GetQrtr() Function Code is given below:


Public Function GetQrtr(ByVal mPeriod As Date) As Integer

Dim mMonth As Integer

On Error GoTo GetQrtr_Err

mMonth = Month(Nz(mPeriod, 0))

If mMonth > 0 Then
    GetQrtr = Choose(mMonth, 1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4)
else
    GetQrtr = 0
End If

GetQrtr_Exit:
Exit Function

GetQrtr_Err:
GetQrtr = 0
Resume GetQrtr_Exit
End Function

The GetQrtr() Function takes the date value as parameter. The Month() Function extracts the month number from date and uses it as parameter for the Choose() Function to pick the correct Quarter Number from it's list.

When the month value is 1,2 or 3 the GetQrtr() function returns 1 to the calling procedure. The Function can be called from a Query, from other Functions, from Form control or from a Report Control by passing date as parameter. When date value passed to the function belongs to April, May, June will returns 2. These months belongs to the Second Quarter of the Year. Dates from next three months returns 3 and so on.


Let us see how we can use this Function in a Sales Query to extract data for Second Quarter 2017 Sales Report. Sample SQL of a data filtering Query is given below:


SELECT SALESTABLE.*
FROM SALESTABLE
WHERE (((SALESTABLE.SALESMANCODE="ABC") AND ((GetQrtr(([SALESDATE]))=2));


The GetQrtr() function extracts the Quarter number from all the Sales Record Dates, based on the Values we have lined up in the Choose() Function inside the GetQrtr() Function, compares them with the criteria parameter value 2 and filters the records for that period.


You may setup a Parameter Variable within the Query so that it will prompt for the criteria value, when the Query Runs, and can input the required value directly to filter the data for report.


When Financial Year is from April to March next Year (Jan - Mar become 4th quarter) still the filter criteria will be 1 to extract the data for the fourth quarter. The report heading Labels will indicate that the report is for the fourth quarter of Financial Year 2017-18.

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Finding Last Day of Week

How to find the week-end date or first-day date of a week using Current Date as input.  Or find first/last-day date of any week by giving a date value as input.

These kind of calculations may become necessary to find week-end date and use it as criteria in queries, filter data for viewing or printing of Reports for sharing of information.

Wherever you need it you can use the following simple expression to find the week-end date of current week:

LastDayOfWeek = Date()-WeekDay(date())+7

If current date is 14th June, 2017 (or any date between 11 and 17 June 2017) then the value returned in variable LastDayOfWeek = 17th June, 2017.

To find the first-day date of the current week use the following method:

FirstDayOfWeek = date()-WeekDay(date())+1

Assuming current date is 14th June, 2017 (or any date between 11 and 17 June 2017) the first-day date of the week returned in variable FirstDayofWeek = 11th June, 2017.

By giving a specific date as input to the expression to find the last-day date of the week:

dtValue = #06/27/2017#
LastDayOfWeek = dtValue - WeekDay(dtValue)+7
Result: 1st July 2017

If you would like to do it differently then try the following expression:

x = #06/27/2017#
'To find the last-day date of the Week:
LastDayofWeek = DateSerial(Year(Date()),1,1)+DatePart("ww",x)*7-1
Result: 1st July, 2017
'To find the first-day date of the Week.
FirstDayofWeek = DateSerial(Year(Date()),1,1)+DatePart("ww",x)*7-7
Result: 25th June, 2017

 

Define it as a Function in a VBA Module and call it wherever you want it, with a date value as parameter. Sample Function code is given below:

Public Function WeekLastDay(ByVal dtVal As Date) As Date
'Date value as input
   WeekLastDay = dtVal - WeekDay(dtVal) + 7
End Function

 

Public Function WeekFirstDay(ByVal dtVal As Date) As Date 
'Date value as input 
    WeekFirstDay = dtVal - WeekDay(dtVal) + 1 
End Function
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Time Value Formatting Beyond Twenty Four Hours

Time Format: hh:mm:ss, returns time values up to 23 hours 59 minutes and 59 seconds (23:59:59) and restarts with the value 00:00:01 for next day, 1 second after midnight 00:00:00.  With the built-in Format() Function we cannot format time values beyond 24 hours, like 45 Hours 30 minute and 15 seconds (45:30:15).

Then how do we format time values beyond twenty four hours for applications, like formatting total hours worked by an employee for a week: 40:30:15 or an IT Firm employee's total internet browsing time for the month: 115:47:12, extracted from Server Logs.

We need a function of our own for this purpose.  The following VBA Function: FormatTime() accepts time values in different form, will do the job.  I  have created this function for you and you may Copy Paste the VBA Code into a Standard Module of your project for use.

Public Function FormatTime(ByVal StartDateTime As Variant, Optional ByVal EndDateTime As Variant = CDate(0)) As String
Dim v1 As Double, hh As Integer, nn As Integer, ss As Integer
'-------------------------------------------------------------------------
'Remarks: Time-Format function for time value beyond 23:59:59
'Author : a.p.r.pillai
'Date   : August-2016
'Rights : All Rights Reserved by www.msaccesstips.com
'
'Input options
'1. StartDatetime & EndDateTime (both date/time values or both Time Values)
'2. StartDateTime = Date/Time Value and EndDateTime value=0
'3. StartDateTime = Time Value in decimal format – e.g. 0.999988425925926) for TimeValue("23:59:59") or less
'4. StartDateTime = Time Value in Seconds – e.g. 86399 for Timevalue("23:59:59")*86400
'-------------------------------------------------------------------------
'VALIDATION SECTION

'If Input Value is in whole seconds (TimeValue*86400)
'for applications like internet Server log time etc.
'Option4

On Error GoTo FormatTime
If TypeName(StartDateTime) = "Long" Then
   GoTo Method2
End If

If EndDateTime > 0 And EndDateTime < StartDateTime Then
'End-Date is less than Start-Date
   MsgBox "Error: End-Date < Start Date - Invalid", vbCritical, "Format_Time()"
ElseIf (EndDateTime > StartDateTime) And (StartDateTime > 0) Then
'option 1
   If TypeName(StartDateTime) = "Date" And TypeName(EndDateTime) = "Date" Then
     v1 = EndDateTime - StartDateTime
     GoTo Method1
   End If
ElseIf StartDateTime > 0 And EndDateTime = 0 Then
'option 2
'Is it Today's date & Time
   If Int(StartDateTime) = Int(Now()) Then
      'Remove Date number and take only time value
      v1 = StartDateTime - Int(StartDateTime)
   Else
   'Option 3
      'Assumes Value is Time-Value in decimal format
      v1 = StartDateTime
   End If
End If

'Option 1 to 3
Method1:
hh = Int(v1 * 24)
nn = Int((v1 - hh / 24) * 1440)
ss = Round((v1 - (hh / 24 + nn / 1440)) * 86400, 0)
FormatTime = Format(hh, "00:") & Format(nn, "00:") & Format(ss, "00")
Exit Function

'Time Input in Seconds
'Option 4
Method2:
v1 = StartDateTime
hh = Int(v1 / 3600)
nn = Int((v1 - (hh * 3600#)) / 60)
ss = v1 - (hh * 3600# + nn * 60)
FormatTime = Format(hh, "00:") & Format(nn, "00:") & Format(ss, "00")

FormatTime_Exit:
Exit Function

FormatTime_Err:
MsgBox "Error: " & Err & " - " & Err.Description, , "FormatTime()"
Resume FormatTime_Exit

End Function

Let us try few examples so that you will know how the function parameter values are correctly input to the function.  You may try the following examples by typing them directly on the VBA Debug Window.

The FormatTime() function accepts two Date/Time or Time input parameter values to the function, second parameter is optional.  The following conditions apply when parameter values are passed to the function:

  1. When both parameters are entered both should be either Date/Time Values or both Time Values.  Difference of time will be calculated by subtracting first parameter value from second parameter.
  2. Second parameter is optional. If omitted then Date value will be ignored when Date/Time value is passed in the first parameter. Time value will be formatted and displayed.
  3. First parameter can be time value in decimal format (e.g. 0.999988425925926 ). Omit second parameter.
  4. First parameter is acceptable as time value in Seconds (e.g. 86399). Omit second parameter.

Example-1: Both Parameter values are Date/Time Values. Second Parameter value (Date or Time) should be greater than first parameter value.

StartDT = DateAdd("d",-2,Now()) = 8/27/2016 7:38:22 PM 

EndDT = Now() = 8/29/2016 7:41:13 PM

? FormatTime(StartDT,EndDT)

Result: 48:02:51

Example-2: First parameter Date/Time Value, second parameter optional and omitted.

SDateTime=Now() or DateVallue("08/29/2016")+TimeValue("18:30:15")

? FormatTime(SDateTime)

Result: 18:30:15

Example-3: First parameter Time Value input as a number (2.00197916667094), the decimal value equal to the first example Result: 48:02:51). When we subtract Start-Date/Time Value from End-Date/Time Value you will get the difference as a decimal number, equal to number of days and time value.  This time number can be the result of summary of time values of several records from a Table or Query. The whole number represents number of days (i.e. 2*24=48 hrs.) + the fractional part in hours:minutes:seconds.

StartDT = 2.00197916667094 

? FormatTime(StartDT)

Result: 48:02:51

If the whole number at the left side of the decimal point is equal to the current date number then it will be ignored, when second parameter is omitted.

You can create a time number similar to the one above for testing this function. To do that we will look at few basics on the time value to understand them better.

1 Day = 24 hours. 1 Hour = 60 Minutes. 1 Minute = 60 Seconds. So 1 Day = 24 * 60 * 60 = 86400 Seconds.

1 second before mid-night = 86400-1 = 86399 seconds = 23:59:59

To convert the time 23:59:59 (86399) into internal representation of time value, divide 86400 into 86399 (86399/86400). Result: 0.999988425925926. The time 23:59:59 is stored in computers memory in this form. When combined with the current date number it will be like: 42612.999988425925926 for 08/30/2016 23:59:59

Let us input this time number alone to our function and try out the result.

? FormatTime(0.999988425925926)

Result: 23:59:59

Example-4:

So, if you want to convert a Time number into Seconds then multiply it with 86400. 0.999988425925926 * 86400 = 86399

You can input number of seconds as a time number as first parameter to get it formatted in Hours:Minutes:Seconds.

? FormatTime(86399)

Result: 23:59:59

If you want larger values for testing this function, then try the following examples.

SD = 86399+86400+86000
   = 258799 seconds

SD = SD/86400
   = 2.9953587962963 time number

? FormatTime(SD)

Result: 71:53:19

Let us input the time value in seconds (let us assume that this value is the summary of Internet browsing time value in seconds).

SD= 258799

? FormatTime(SD)

Result: 71:53:19

If you have a Library Database then you can move this Function into that database so that you don't have to copy the code into all your other databases.

A Library database is a common database you have created with all your custom functions or custom wizards that you can attach with your other Projects. This method will enable you to use these functions in your other projects without duplicating codes in all of them. For a detailed discussion on this subject visit the page MS-Access and Reference Library.

Please leave your comments or suggestions for improvement of FormatTime()  function in the Comments Section, at the end of this Post. Thank you.

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Opening Multiple Instances of Form in Memory

Last few weeks we have been through learning the usage of dot(.) separator and exclamation symbol(!) in VBA object references.  Now, we will explore some interesting trick with Forms in VBA.  How to Call a Function Procedure embedded in a Form Module (Class Module), from a program outside the Form?

We will explore two different aspects on this particular topic.

  1. How to open several instances of a single Microsoft Access Form in memory, displaying different information on each of them?

    Sample screen shot of two instances of Employees Form is given below for reference.  The first form is behind the second instance of the form, displays employee details of ID: 4 & 5.   Click on the image to enlarge the picture. 

  2. How to call a Function Procedure on the Form Module, from outside the Form?

    Call the Function from a Standard Module,  from the Module of another form or from the VBA Debug Window (Immediate Window).  The target form must be opened in memory in order to call the function procedure of the form from outside.

Function Procedures in a Form module is helpful to avoid duplication of code. It can be called from subroutines in different locations on the same Form, from a command button click or from some other Event Procedures of the Form.  The function procedure on a Form Module can be anything that does some calculation, validation check, updating the information or a stand-alone search operation procedure, like the one we are going to use on our sample Employees Form.

All the Event Procedures on a Form Module are automatically declared as Private Subroutines and they all will start with the beginning  and end Statements, like the sample statements given below.   Our own VBA codes that does something goes within this block of codes:

Private Sub Command8_Click()
.
.
End Sub

The scope of Private declared Subroutine/Function stays within that module and cannot be called from outside.  Private declaration is absolutely necessary to avoid procedure name clash with the same name on another Class Module or Standard Module.  Form Function Procedure must be declared as Public in order to call it from outside the Form.

To perform a trial run of the above trick you need the Employees Table and a Form.

  1. Import Employees Table from Northwind.accdb sample database.
  2. Click on the Employees Table to select it.
  3. Click on Create Ribbon.
  4. Click on Form Button, from the Forms group, to create a Form, like the image given above, for Employees Table.
  5. Save the Form with the name frmEmployees.
  6. Open the frmEmployees Form in Design View.
  7. Click on the View Code button, in Tools button group, to open Form Module.
  8. Copy the following VBA Code and Paste them into the VBA Module of the Form.
    Public Function GetFirstName(ByVal EmpID As Integer) As String
    Dim rst As Recordset, crit As String
    Dim empCount As Integer
    
    'get total count of employees in the Table
    empCount = DCount("*", "Employees")
    
    'validate employee code
    If EmpID > 0 And EmpID <= empCount Then
    'create search criteria
        crit = "ID = " & EmpID
    'make a clone of the recordset of the Form
        Set rst = Me.RecordsetClone
    'Find the first record that matches the criteria
        rst.FindFirst crit
    'If the record is found then
        If Not rst.NoMatch Then
    'copy the recordset bookmark to the form bookmark
    'this will make the found record current on the form
         Me.Bookmark = rst.Bookmark
    'Return the Employee first name to the calling program
         GetFirstName = rst![First Name]
        End If
    'close the recordset clone and release the used memory
        rst.close
        Set rst = Nothing
    'IF EmployeeID is not in range of 1 to empCount
    Else
    'then display a message and exit function
        MsgBox "Valid Employee IDs: 1 to " & empCount
    End If
    
    End Function
    
  9. Save and Close the Form.

Have you noticed the starting line of the above Function that is declared as Public?

The Function GetFirstName() accepts Employee ID number as parameter, finds the record and makes that record current on the form. The Function returns the First Name of the Employee to the calling program,  if the search was successful.  If the search operation fails then it gives a warning message, saying that the employee ID code passed to the function is not within the range of ID codes available in the Employees table.

Now, we need another program, in the Standard Module, to run the search function GetFirstName() from the frmEmployees Form Module.  Besides that this program demonstrates as how to create more than one instance of a Microsoft Access Form and open them in memory, to access their properties, methods or control contents.

  1. Open VBA Editing Window (Alt+F11).
  2. Select Module from Insert Menu and add a new Standard Module.
  3. Copy and paste the following VBA Function code into the new Module.
    Public Function frmInstanceTest()
    
    'Create first instance of the form frmEmployees
    'and opens it in memory(not visible in application window)
          Dim frm As New Form_frmEmployees
    
    'Create second instance of the Form frmEmployees
    'and opens it in memory(not visible in application window)
          Dim frm2 As New Form_frmEmployees
    
    'Name1, Name2 string variables
          Dim Name1 As String, Name2 As String
    
    'Make both instances of the frmEmployees
    'visible in the Application Window
    
      frm.Visible = True
      frm2.Visible = True
    
    'Call the GetFirstName() Public Function of
    '1st instance of the frmEmployees with Employee ID: 4
    'Record of ID 4 becomes current on frmEmployees
    'and returns first name to variable Name1
    
      Name1 = frm.GetFirstName(4)
      
    'Call the GetFirstName() Public Function of
    '2nd instance of the frmEmployees with Employee ID:5
    'Record ID 5 becomes current on frmEmployees
    'and returns first name to the variable Name2
    
      Name2 = frm2.GetFirstName(5)
    
    'pause execution of this code to view
    'the Employees Form instances in Application Window.
    
    Stop
    
    'display the first names retrieved from
    'both instances of the Employees Form
      MsgBox "Employees " & Name1 & ", " & Name2
    End Function
    

Let us run the code and view the result in Application Window.

  1. Click somewhere within the body of frmInstanceTest() function and press F5 key to run the code.

    The program will pause at the Stop statement and this will facilitate to view the Application window, where the frmEmployees Form instances are open in normal view mode, one overlapping the other.

  2. Press Alt+F11 to display the Application Window displaying both instances of the Form, second form overlapping the first one.
  3. Click and hold on the title bar area of the top form and drag it to the right, to make part of the form behind visible.

    Check the employee records on both forms, they are different, one with employee code 4 and the other is 5.  Check the title area of forms, both are showing frmEmployees title.  Now, let us come back to the program and continue running the code to complete the task.

  4. Press Alt+F11 again to switch back to the VBA Window and press F5 key one more time to continue executing the remaining lines of code.

    The Message Box appears in the Application Window displaying the Employee name Mariya and Steven together.  When you click OK Button on the MsgBox the frmEmployee form instances disappears from the Application Window.

  5. Click OK button on the MsgBox.

Note: I would like to draw your attention to the Stop statement above the MsgBox() function, at the end part of the code. The Stop statement pauses execution of the VBA code on that statement.  Normally, this statement is used in a program for debugging of code, to trace logical errors and corrections.  Here, it is required to pause execution of code so that we can go to the Application Window and view both instances of the frmEmployees Form there.  The MsgBox() will pause the code but we will be able to view the topmost instance of the form only. We cannot drag the top form to the right side while msgBox is displaced.

If we doesn't create a pause in the code execution both instances of the form are closed immediately, when the program ends.  In that case we will not be able to view the forms.  Since, it is a trial run we would like to know what is happening in the program.

Let us take a closer look at each line of code of the frmInstanceTest() function.  Even though hints are given on each line of code, explaining few things here will make them more clear to you.  We will start with the first two Dim Statement.

Dim frm As New Form_frmEmployees
Dim frm2 As New Form_frmEmployees

In the above Dim statement you can see that the New key word followed by the object reference. The object name is our frmEmployees prefixed by the direct Object Class name FORM followed by an underscore character separation (Form_) to the frmEmployees Form name (Form_frmEmployees).  These Dim statements itself  opens two instances of the frmEmployees in memory.   Form instances opened in this way is not immediately visible in the Application Window.  If we need them to be visible then make them visible with another statement.

Next we have declared two String Variables: Name1 & Name2 to hold the names returned by the GetFirstName() method.

Next two statements: frm.Visible=True and frm2.Visible=True, makes both instances of frmEmployees Form visible in the Application Window.

In Next two lines of code we are calling the GetFirstName() method of first and second instances of the frmEmployees to search, find and return the First Names of employee code 4 and 5.

The default instance of a Form openes in the following manner in programs for accessing their Properties, Methods and Controls.  These style of statements are always used to open a form in programs. The default instance will be automatically visible, when it is open, in the Application Window.

Dim frm as Form 'define a Form class object
DoCmd.OpenForm "frmEmployees", vbNormal 'open frmEmployees in Memory
Set frm3 = Forms!frmEmployees ' attach it to the frm object

Assume that we have opened frm & frm2 instances first in memory before the default instance through the above code.  How to address those three instances in a program to do something?  Let us forget about the frm, frm2, frm3 object references for now, we will go by the straight method, like the one given below:

name3 = Forms![frmEmployees].GetFirstName(5) 'target form in memory is the default instance
'OR
name3 = Forms("frmEmployees").GetFirstName(5) 
'OR
name3 = Forms(2).GetFirstName(5) ' this is the third and default instance

The other two instances in memory cannot be referenced like the first two default methods, using the name of the form. You have to use only the index number of Forms collection to address the other two instances.

name1 = Forms(0).GetFirstName(3)
name2 = Forms(1).GetFirstName(6)

There is a shortcut method you can use to run the GetFirstName() Method of the frmEmployees Form from the debug window (Ctrl+G).  Type the following command on the Debug Window and press Enter Key:

? form_frmEmployees.GetFirstName(5)
'Result: Steven
'OR
X = form_frmEmployees.GetFirstName(5)

What happens when we execute the above command?  It opens an instance of the frmEmployees in memory, Calls the Function GetFirstName() with the employee Code 5. The GetFirstName() runs and finds the record and returns the First Name of the employee and closes the form.

Tip: Even after closing the Form, after execution of the above command, the current record of Employee ID 5 remains as current on the closed Form.

You can check this by executing the following shortcut command by typing it in the debug window and pressing Enter Key.

? form_frmEmployees![First Name]
'Result: Steven

In the above command we didn't run the GetFirstName() method but directly printed the First Name from the current record on the form. If you want get little fancy with the command then try this by typing it in debug window and press Enter Key:

MsgBox "First Name: " & form_frmEmployees.GetFirstName(8)
'OR
MsgBox "First Name: " & form_frmEmployees![First Name]

Or try the above command from a Command Button Click Event Procedure from another Form's Module, as given below.

Private Sub Command8_Click()
  MsgBox "First Name: " & Form_frmEmployees.GetFirstName(8)

End Sub
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Dots and Exclamation Marks Usage with Objects in VBA3

MS-Access Application Objects (Table, Query, Forms, Text box, Label etc.) needs some meaningful names, when we create them. If we don't, then MS-Access assigns default names, like Form1, Form2, Text1, Label1 and so on. These default names doesn't give any clue as what those names represents. We are free to assign appropriate names in relation to what we are building in the Database. That way it is easy to remember those names (if not all of them), when we need them in calculations,  in VBA or in wherever they are referenced. We need these names to address them easily in VBA, like Forms!Employees!Salary rather than the usage  Forms("Employees").Controls("Salary").Value. 

Last week we have started with a simple example, where we can use the symbol ! , to shorten the lengthy object address when dot separators are used, giving you enough insight into what it is all about. When we have the Form’s name and Control name the expression can be written in short form with the symbol ! .  This is true when recordset fields are referenced, like rset!LastName instead of rset.Fields(0).Value.

If you are new on this page then please visit the earlier two pages and continue from here. The links are given below:

I will repeat the first example here, introduced in the first page of this three page series, to go further on this discussion.

? Forms!frmMain!frmSubForm.Form!frmInsideSubForm.Form!Text7
'
'The above command without the use of the ! Symbol, you must write it in the following manner to get the same result.
'
? Forms("frmMain").Controls("frmSubForm").Form.Controls("frmInsideSubForm").Form.Text7.value

Note: The frmSubForm when placed as Sub-Form on the frmMain it becomes a control (with it's own controls and properties) of the Main Form and listed among the Controls list. If we take a list of controls of the Main form we can see that the frmSubForm is listed among them.

Open a Form with a Sub-Form  then type the following command in one line, with changes in the Debug Window and press Enter Key to get a listing of control names of main form

for j=0 to forms!frmMain.controls.Count-1:? j, forms!frmMain.controls(j).name:next
'Result of the above command, on my Form.
'
 0            Label0
 1            Text1
 2            Label2
 3            Text3
 4            Label4
 5            frmSubForm
 6            Label5

frmSubForm is listed as a Control of the frmMain with index number 5

Now, about the example given at the beginning, we have three open Forms: frmMain, frmSubForm & frmInsideSubForm, layered one inside the other. We are trying to print the Text7 Text Box contents, from the innermost form in the debug window.  Look at the above address of  Text7 textbox, all elements are joined with the symbol ! except .Form after the name frmSubForm and frmInsideSubForm. This command will work without the .Form part, try the command given below.

? Forms!frmMain!frmSubForm!frmInsideSubForm!Text7

If the address works without the .form part why we need it in the address and what it means? It works without explicit reference because the system knows that it is a Sub-Form control by default.

When you drag and drop a Sub-Form on to the Main Form Microsoft Access creates a container control on the main form and inserts the Sub-Form into it. To be more specific, if you select the outer edge of the sub-form control you can select this container control. Display it's Property Sheet(F4) check the Source Object Property setting. You can see that the sub-form's name is inserted there. This is the control where we set the Link Master Fields and Link Child Fields properties to set relationship between data on master form and sub-form.

You can re-write this property value with any other form's name  to load another form into it, in real-time. When you do that consider the relationship change, if the new form's source data is not related.

Coming back to the point, i.e. what the .Form part in the above address means? It means that the Sub-Form Control created by Access is a control for loading a Form into it and it will be always a form-control, whether you explicitly add the .Form part in the address or not.

But, the interesting part is that you can insert a Table or a Query (not Action Query) into this control as well.

Try that, if you have a Form with a sub-form, open it in design view.

  1. Click on the outer edge of the Sub-Form to select the Sub-Form control.
  2. Display the Property Sheet (F4) and select the Source Object Property.
  3. Click on the drop-down control to the right of the property to display the available forms, Tables and Queries.

    On top of the list all forms will appear, after that the list of Tables and then the Queries list. All the Tables are listed with Table.TableName format and queries with Query.QueryName format indicating the category of object you can insert into the Source Object Property of the Form control.

  4. Select a Table or Query to insert into the Source Object Property of the Sub-Form control.
  5. Save the Form and open it in Form View.
  6. You will find the Table or Query result is displayed in the Sub-Form control.

  7. Try to print the value of one of the field in display in the debug window.

    Tip: It will print the value of the active record in the sub-form, if selected, otherwise the first record field value.

Is this the command you have typed in the Debug Window?

? Forms!frmMain!frmSubForm.Table!LastName

Then you are wrong, it is not a Table Control, still it is a Form control only. When you set the Source Object Proerty Value with a Table's name the system already added the category name to the object's name (Table.TableName or Query.QueryName) to identify what type of object is loaded into the sub-form control.

So the correct command is:

? Forms!frmMain!frmSubForm.Form!LastName
'
'OR
'
? Forms!frmMain!frmSubForm!LastName
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Dots and Exclamation Marks Usage with Objects in VBA2

Last week we have started with few examples of the usage of dots (.)  and exclamation marks (!) on memory loaded Form/Report Objects.  We will continue exploring this topic further.  If you have not gone through the earlier page,  please visit that page and then continue from here. Earlier article link: Dots and Exclamation Marks usage with Objects in VBA

After going through last week's article, I am sure you are little bit confused, which syntax is the easy one to use because we have tried different syntax for addressing form & control in VBA.

For the time being we will leave that there and try few things differently here so that you will be better informed about the dot separator usage on built-in objects.  The  exclamation (!) symbol is not at all valid for referencing these objects.  You will see the hierarchy set up of some of the library objects visually and how to address them to view their property values or call their methods directly from the debug window. 

Object Library View.

  1. Open your Access Database.
  2. Open VBA Editing Window (Alt+F11).
  3. Open Debug Window (Ctrl+G).
  4. Display Object Browser Window(F2).
    • Select Options from Tools Menu.
    • On the Editor Tab put a check-mark on the Auto List Members item, if it is not already selected.
  5. Select Access from the <All Libraries> Control's drop-down list.
  6. Move the scrollbar of Classes window down, find the item CurrentProject and select it.

    Check the right side window listing of  CurrentProject’s Properties and Methods.

  7. If the Object Browser Window is small then drag the right and bottom edges to make it large enough to display all the Properties and Methods of the CurrentProject Object in the right-side window.
  8. Click and hold on the Title area of the object browser window and drag it to the right, if it overlaps the Debug Window area.

When you select a Class Object or Public Constant definition from the Classes Window (left panel), the selected object members are displayed in the right-side window.

Let us display information stored in some of these objects and how we address those object properties/methods and in which order we specify them?

We will display the full Pathname (.FullName property value) of the active database with the following command, by typing it in the Debug Window and pressing Enter Key:

? Access.CurrentProject.FullName
'Result: G:\New folder\pwtracker.accdb

The .FullName Property Value of CurrentProject Object from Access Library of Objects is displayed.  When you open a database from a particular location the .FullName Property value, the full pathname of the Database,  is set by MS-Access System.  We have joined the object elements in correct sequence separated by dots to specify the .FullName property at the end. The .Name property value will display the database name part only.

Let us see how many forms you have in your database, by taking the .Count Property Value of AllForms Object.

? Access.CurrentProject.AllForms.Count
'Result: 75 – There are 75 user created Forms in my active database.
'
? Access.CurrentProject.AllForms.item(50).Name
'Result: frmEmployees 
'
'The 50th index numbered item (i.e. 51st item)in my database is frmEmployees. 
'This Form is not opened in memory, but it is taken from the Database’s .AllForms Collection. 
'
? Access.CurrentProject.BaseConnectionString
'
'Result: PROVIDER=Microsoft.ACE.OLEDB.12.0;DATA SOURCE=G:\New folder\pwtracker.accdb;PERSIST SECURITY INFO=FALSE;Jet OLEDB:System database=G:\mdbs\BACAUDIT_1.MDW
'

In the above examples we have displayed CurrentProject Object's few Property Values assigned by the System. We have used Forms Collection Object to address the open forms in memory, in last week's examples.

Note: You may explore some of the other objects yourself.

From the above few examples you can see that we have used dot separator character only to join each object/property. You cannot use ! symbol to address predefined objects, methods or properties.

When we reference a User-Defined object (it should have a name) we can use ! symbol followed by the object/control Name to access that Control's Value or other controls/properties, eliminating the lengthy syntax. To make this point very clear we will try out one simple example below.

  1. Scroll down to the bottom of the Classes Window.
  2. Select the TempVars Class Object. You can see it's Methods (.Add(), .Remove() & .RemoveAll()) and Properties in the right side window.
  3. Above the TempVars Class you can see another object name TempVar Class, click on that and check the right-side window. You will find only two properties:Name & Value.
  4. Type the next line of Code in the Debug Window and press Enter Key.
TempVars.Add "website", "MsAccessTips.com"

We have called the .Add() method of the TempVars Collection Object to instantiate the TempVar Class, to assign the Name property with the text: website and the Value property with the text: MsAccessTips.com. The new Tempvar Variable website is added to the TempVars Collection with index number 0, because this is the first TempVar variable we have defined in memory so far.

The TempVar data type is Variant Type, i.e. whatever data type (Integer, Single, Double, Date, String etc.) you assigned to it, it will automatically adjust to that data type.

We can display the website variable contents in two different ways.  First method using dot separators, second with ! symbol.

'1st method
? TempVars.item(0).value
'Result: MsAccessTips.com
'OR
? TempVars.item("website").value
'Result: MsAccessTips.com
'
'OR
X="website"
? TempVars.item(X).value
'Result: MsAccessTips.com
'

'2nd method
'the above lengthy syntax can be shortened
'with ! symbol and the user-defined name:website
'point to note:after ! symbol Name property value should follow.
? TempVars!website
'Result: MsAccessTips.com
'
'next command removes the website variable from memory.
TempVars.Remove "website"
'
'the .RemoveAll method clears all the user-defined Temporary Variables from memory.
'TempVars.RemoveAll

The TempVars Variables are Global in nature, that means you can call this variable (Tempvars!website) in Queries, Textbox (=TempVars!website) on Forms or on Reports and in expressions like: ="Website Name is: " & TempVars!website. If the Value property is assigned with numerical values (like Exchange Rates or some common factor) it can be used in Calculations.

Tip: Try defining few more TempVar variables assigning different data types: Integer, Double, Date etc. with appropriate Name Property Values.

The Tempvar variable with the name website is our own creation and it is in memory.  Objects (Form/Report) should be loaded into memory with their controls (Textbox, Combobox, Labels, Sub-Form/Sub-Report etc,) to address them with the use of ! symbol followed by the name of the control.

We have used the keyword .item in the first three examples.  This is used immediately after the TempVars Collection Object.  When we address textboxes, labels and other controls on an open Form/Report we must use the key word .Controls.

You may explore other objects by selecting it in the left-side panel and inspecting their properties, methods and events etc. now or later when you are in doubt on something.

Tables & Queries are part of DAO Library. You may select DAO in the top control replacing Access and explore DAO related Classes, their Properties and Methods.

Hope you are now comfortable with the usage of (.) and (!) symbols in object references. We will look into few more things in the next session before we conclude the discussion on this topic.

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Dots and Exclamation Marks Usage with Objects in VBA

Beginner VBA enthusiasts often get confused as how to address a control on a Form or on Sub-Forms. It becomes more difficult when there is an inner-form within a Sub-Form. Specifying the address of the control on the inner sub-form correctly will only help to access the Text control's contents or to set the control's value directly through VBA. How, to join each element of the address? Join each element with dot (.) or is it exclamation mark (!) or both?

Let us start with the simple usages of dots and exclamation marks in object specifications.

I have designed a sample Main Form and two Sub-Forms. The second sub-form is inside the first Sub-Form. The Forms design view and normal view images are given below for reference.

Sample Form in Normal View

General Usages of dot (.) and exclamation symbol (!) in object references.

  • dot (.) - used after an object name to access it's methods or properties.
  • exclation mark (!) - used after an object name to refer to the sub-object/control of the Top-level Object.

Sample Forms:

  1. Main Form:
  2. frmMain
  3. Sub-Form of Main Form:
  4. frmSubForm
  5. Inner Sub-Form on frmSubForm:
  6. frmInnerSubForm
  7. Text Control on frmInnerSubForm:
  8. Text7
  9. Another Unbound Text Control on frmInnerSubForm:
  10. Text3

All the three forms are designed without linking to any Table (all form's Record Source Property is empty). All the Text controls on the Form are unbound.

You may design three sample forms with few unbound text boxes and set them up one inside the other and open it in normal view. Open VBA editing Window and open the Debug Window (Ctrl+G). Now you are ready to try out the following examples after typing the code directly on the Debug Window and pressing Enter Key.

First, we will try to read the contents of Text7 textbox (i.e. 'Innermost Form') from frmInnerSubForm and display the result on the Debug Window.

? Forms!frmMain!frmSubForm.Form!frmInsideSubForm.Form!Text7

Printed Result is: Innermost Form

I have written an expression ="Innermost Form" inside the Text7  Text box, that is displayed in the Debug Window.

Forms!frmMain!frmSubForm.Form!frmInsideSubForm.Form!Text3 = "ms-access"

Result: Text3 textbox of the Innermost Form is assigned with the text: ms-access.

Check on your opened Form after executing the above statement on the Debug Window.

Let us examine each part of the above command joined by exclamation mark or dot.   I call this a command because we directly execute this program statement in the Debug Window, with the ? (Print VBA command).

  • Forms : Collection of all Forms loaded in memory. All Forms opened in memory are indexed in the order in which they are loaded into memory, i.e. first form opened will have the index number 0, second form is 1 and so on. If your main form have two more forms on it as Sub-Forms they are treated as controls of the Main-form, like any other control (combobox, labels, textbox etc.). They will not appear as a separate form in the Forms collection. We can display the name of the first open form in memory with the following command using zero as it's index number and printing it's Name Property Value.
     ? Forms(0).Name

    Result: frmMain - Form's Name property value is printed.

    ? Forms(0).Width

    Result: 21225 (you will get a number similar to the one given to the left) - the width of the form given in the measure of Twips. 1 Inch = 1440 twips. VBA converts the value you set in the Width Property of the Form in Inches or Centimeters or any other regional value it will be converted into twips.

    If you know the Form's name then the above command can be given as below:

    ? Forms("frmMain").Width 

    In this form of command Form's name can be given as a string in parenthesis.

    OR

    ? Forms!frmMain.Width

    In this command, immediately after the Forms Collection name we have used the ! symbol to give the name of next level of object of the Forms collection object, not a property or method. The next item Width is a property of the frmMain object, so a dot is required, not the other symbol.

    Note: You cannot use the ! symbol in place of dot (.) to address the Width or Name or any other property of the Form. There are over 200 properties for a form. You can display the Name of all the properties by typing the following Code, on one line, on the Debug Window and pressing Enter Key:

    For j=0 to Forms(0).Properties.count-1:? j,Forms(0).Properties(j).Name:Next

    In the above statement we have called the Count() Method of the Forms Property to take a Count of properties of the first form open in memory and print the Name of each Property, one by one.

    OR

    For j=0 to Forms("frmMain").Properties.count-1:? j,Forms("frmMain").Properties(j).Name:Next

    OR

    For j=0 to Forms!frmMain.Properties.count-1:? j,Forms!frmMain.Properties(j).Name:Next

    Note the usage of Forms("frmMain") and !frmMain, two different ways to refer to the frmMain object of the open Forms Collection Object.  In both cases form's name is given immediately after the open Forms collection name. But,  frmMain form is not open at the time of executing this statement it will end up with Error.  Forms(0) refers to any form that is open first in memory. It will fail only when no form is open at the time of executing this statement.

    ? Forms.Count

    The Count() method of the open Forms Collection Object will print the count of open Forms

We will explore this topic further in the next Post.

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