VBA UserForm TextBox Only Allow Numbers and Empty Text - vba

Question

In my userform I want to MsgBox if TextBox not contain Numbers or empty.
This is my code but in another case when the TextBox = "" Empty the MsgBox appear to me, so the issue with me is the empty TextBox.
Private Sub TB1_Change()
If TypeName(Me.TB1) = "TextBox" Then
With Me.ActiveControl
L12.Caption = Val(TB1.Text) * Val(TB2.Text)
If Not IsNumeric(.Value) And .Value <> vbNullString Then
MsgBox "Sorry, only numbers allowed"
.Value = vbNullString
End If
End With
End If
End Sub

Answer 1

Use the Key Press event for this purpose.
Private Sub TB1_KeyPress(ByVal KeyAscii As MSForms.ReturnInteger)
If Not IsNumeric(Chr(KeyAscii)) Then KeyAscii = 0
End Sub
This procedure will just ignore anything you enter if it isn't a number, but you can modify both the condition and the output. For example, you might allow a decimal point to be entered, or you might wish to show a message box - perhaps only on the second try.

Answer 2

You may use the AfterUpdate event handler instead of the Change event, might also want to use the Exit event and cancel the exit if the user enters an invalid value:
Option Explicit
Private Sub TB1_AfterUpdate()
'Check whether the value is numeric or empty:
If Not IsValNumeric(Me.TB1.Value) Then
MsgBox "Sorry, only numbers allowed"
Me.TB1.Value = vbNullString
Else:
'Do something...
MsgBox val(TB1.Text) * val(TB2.Text)
End If
End Sub
Private Sub TB1_Exit(ByVal Cancel As MSForms.ReturnBoolean)
'Prevents the user from EXIT the TextBox if value is not numeric/empty
Cancel = Not IsNumeric(Me.TB1.Value)
End Sub
Private Function IsValNumeric(val$) As Boolean
Dim ret As Boolean
'check for numeric value only and allow empty value as a zero value
ret = IsNumeric(val) Or Len(val) = 0
IsValNumeric = ret
End Function

Answer 3

You can wait until the user finishes their input and then test the field.
For usability, the message box should be replaced with a caption and an icon/picture like this "A number must be entered here."
These would be displayed next to the text box when the input is incorrect. Then hidden when the input is corrected. The submission of the form can be blocked until all the errors have been corrected.
This allows the user to enter the request data and then fix any input errors. This is better than stopping them every time they make a mistake.
The event is changed from Change to Exit.
Private Sub TB1_Exit(ByVal Cancel As MSForms.ReturnBoolean)
If TypeName(Me.TB1) = "TextBox" Then
With Me.ActiveControl
L12.Caption = Val(TB1.Text) * Val(TB2.Text)
If Not IsNumeric(.Value) Or .Value = vbNullString Then
MsgBox "Sorry, only numbers allowed"
.Value = vbNullString
End If
End With
End If
End Sub
The vbNullString test has also been updated.

Answer 4

Since you are trying to allow only "Numeric" and "Blank" then the code below would deliver your needs.
Private Sub TB1_Change()
if IsNumeric(Me.TB1.Value) = True or Me.TB1.Value = vbNullString then
'Good data, nothing to MSG
Else
MsgBox "Your input data is not valid"
Endif
End Sub