ACC2000: Form Controls to Increment and Decrement a Date (209253)

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Microsoft provides programming examples for illustration only, without warranty either expressed or implied. This includes, but is not limited to, the implied warranties of merchantability or fitness for a particular purpose. This article assumes that you are familiar with the programming language that is being demonstrated and with the tools that are used to create and to debug procedures. Microsoft support engineers can help explain the functionality of a particular procedure, but they will not modify these examples to provide added functionality or construct procedures to meet your specific requirements. The following example demonstrates how to create controls on a form that you can use to increment or decrement a date. It involves a custom function that can be used to increment or decrement any control on the calling form that has a number or date value. The IncOrDecDate function takes a negative or positive integer (in this case a -1 or 1), to indicate how much you want to increment or decrement the date. It also requires the name of the control where the date is located. To try it, follow these steps:

1. Create a new Access database.
2. Create a new module and type the following code:

   Option Compare Database
   
   Function IncOrDecDate(intIncOrDec As Integer, strDateCtrl)
   
   Dim intI As Integer
   Dim objDateCtrl As Object
   
   
   For intI = 1 To 1500            ' Start loop.
       If intI Mod 100 = 0 Then    ' If loop has repeated
                                   ' 100 times.
          DoEvents                 ' Yield to operating
                                   ' system.
       End If
   Next intI
   
   Set objDateCtrl = Screen.ActiveForm.Controls(strDateCtrl)
   
   objDateCtrl.Value = objDateCtrl.Value + intIncOrDec
   
   End Function
   					

3. Create a form not based on any table or query with the following specifications:

      Form: Date Selector
      ----------------------
      Caption: Date Selector
   
      Text Box
      ----------------------
      Name: Call Date
      Format: General Date
      Default Value: =Date()
      Locked: Yes
      SpecialEffect: Sunken
   
      Object: Command Button
      -----------------------
      Name: Decrease
      Caption: <
      AutoRepeat: Yes
      OnClick: Change Date
   
      Object: Command Button
      -----------------------
      Name: Advance
      Caption: >
      AutoRepeat: Yes
      OnClick: Change Date
   					

4. Set the OnClick property of the Decrease command button, to the following expression:

   =IncOrDecDate(-1,"Call Date")

   The "-1" indicates that the Call Date control should be decremented by 1.
5. Set the OnClick property of the Advance command button, to the following expression:

   =IncOrDecDate(1,"Call Date")

   The "1" indicates that the Call Date control should be incremented by 1.
6. Open the Date Selector form. The date defaults to your computer's system date. Click the > button to increase the date. Click the < button to decrease the date.

The date continues to change while the button is depressed. Note that although the pointer can be moved into the Date text box with the TAB key, the date cannot be changed except by using the command buttons.