Microsoft Access Database Programmer Baton Rouge LA

Microsoft Access Programmer Information

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The following material is shared here to indicate our commitment to professional Microsoft Access programmer services in the Baton Rouge LA area. Access programming for business is highly complex and requires dedication and skill to create a high quality database application. We wrote the book on Microsoft Access prgramming, so you know you will get the best possible Access database solution for your business.

Looping

Several looping structures are available in VBA; most are discussed in this section. Take a look at the following example of a looping structure (found under the Do While...Loop command button of the frmControlStructures form):

Sub cmdDoWhileLoop_Click()

Do While Nz(Me.txtAge.Value)< 35

Me.txtAge.Value = Nz(Me.txtAge.Value) + 1

Loop

End Sub

In this structure, if the value in the txtAge text box is greater than or equal to 35, the code in the loop is not executed. If you want the code to execute unconditionally at least one time, you need to use the following construct (found under the Do...Loop While command button of the frmControlStructures form):

Sub cmdDoLoopWhile_Click()

Do

Me.txtAge = Nz(Me.txtAge.Value) + 1

Loop While Nz(Me.txtAge.Value) < 35

End Sub

This code will execute one time, even if the value in the txtAge text box is set to 35. The Do While...Loop in the previous example evaluates before the code is executed, so it doesn't ensure code execution. The Do...Loop While is evaluated at the end of the loop and therefore guarantees execution.

Alternatives to the Do While...Loop and the Do...Loop While are Do Until...Loop and Do...Loop Until. Do Until...Loop (found under the Do Until...Loop command button of the frmControlStructures form) works like this:

Sub cmdDoUntil_Click()

Do Until Nz(Me.txtAge.Value) = 35

Me.txtAge.Value = Nz(Me.txtAge.Value) + 1

Loop

End Sub

This loop continues to execute until the value in the txtAge text box becomes equal to 35. The Do...Loop Until construct (found under the Do...Loop Until command button of the frmControlStructures form) is another variation:

Sub cmdLoopUntil_Click()

Do

Me.txtAge.Value = Nz(Me.txtAge.Value) + 1

Loop Until Nz(Me.txtAge.Value) = 35

End Sub

As with the Do...Loop While construct, the Do...Loop Until construct doesn't evaluate the condition until the end of the loop, so the code in the loop is guaranteed to execute at least once.

CAUTION

With any of the looping constructs, it's easy to unintentionally cause a loop to execute endlessly, as is shown in this example and can also be illustrated with the code samples shown previously. (This code is not included in CHAP8EX.)

Sub EndlessLoop()

Dim intCounter As Integer

intCounter = 5

Do

Debug.Print intCounter

intCounter = intCounter + 1

Loop Until intCounter = 5

End Sub

This code snippet sets intCounter equal to 5. The code in the loop increments intCounter and then tests to see whether intCounter equals 5. If it doesn't, the code in the loop executes another time. Because intCounter will never become equal to 5 (it starts at 6 within the Do loop), the loop executes endlessly. You need to use Ctrl+Break to exit the loop; however, Ctrl+Break doesn't work in Access's runtime version.

Access Programmer for Baton Rouge LA Attribution

This material originally appeared in Alison Balter's book Mastering Microsoft Office Access 2007 Development. Reprinted here by author's permission.

When you need a Microsoft Access programmer for your Baton Rouge LA business, call MS Access Solutions at (323) 285-0939. We have over 25 years experience in Microsoft Access programmer solutions. We create Access database applications for all sectors, consisting of hospitals, government agencies, the U.S. military, universities, agriculture, workers services, and insurance provider. We can take care of the most advanced as well as complicated Access and SQL Server database programming for your business as well as smaller projects, like fixing damaged Access database forms, MS Access reports, Access macros, and VBA code.

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