How can I force a number in a textbox using Access VBA?

To force a textbox to accept only numeric input in Microsoft Access using VBA, you can use the KeyPress event of the textbox. This event allows you to intercept keystrokes before they are processed by the control.

Here's how you can do it:

1. Open Your Form in Design View:

- Open the form containing the textbox you want to modify in design view.

2. Open the VBA Code Editor:

- Select the textbox, go to the "Event" tab in the Property Sheet, and click on the "..." button next to the "On Key Press" event. This will open the VBA editor.

3. Insert the VBA Code:

- In the VBA editor, insert the following code within the TextBox_KeyPress event (replace TextBox with your actual textbox name):

Private Sub TextBox_KeyPress(KeyAscii As Integer)
  Select Case KeyAscii
    Case vbKey0 To vbKey9, vbKeyBack, vbKeyDecimal, vbKeyMinus
    ' Allow numeric characters, backspace, decimal point, and minus sign
    Case Else
    KeyAscii = 0 ' Suppress other characters
  End Select
End Sub

4. Explanation of the code:

- The KeyPress event is triggered each time a key is pressed.

- KeyAscii represents the ASCII code of the pressed key.

- The Select Case statement checks if the pressed key is a digit (vbKey0 to vbKey9), a backspace (vbKeyBack), a decimal point (vbKeyDecimal) or a minus sign (vbKeyMinus).

- If it's one of these allowed keys, the code does nothing, and the character is entered into the textbox.

- For other keys, the code sets KeyAscii = 0 which effectively suppresses the character from being entered into the textbox.

5. Allowing Negative Numbers:

- If you want to allow negative numbers, including the vbKeyMinus is necessary. However, this also allows the minus sign to be entered at any position. You might want to add more complex logic if you want the minus sign only at the beginning of the number.

6. Allowing Decimal Points:

- Including vbKeyDecimal allows the user to enter a decimal point. You should consider preventing multiple decimal points for a robust solution.

7. Testing the Implementation:

- Close the VBA editor and switch back to the form view. Now, the textbox will only accept numeric input, along with backspace, decimal point and minus sign.

This method ensures that only valid numerical input is entered into the textbox, which helps with data validation and prevents errors later in your application. You can modify the Case statements to allow other special characters, if necessary.

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