How to make auto calculate???

[zahir]

Hi everyone i have one question..

How to make auto calculation in textbox without press the button?
Example i have Textbox1 + Textbox2 = Textbox3
in the textbox3 it will auto calculate the value...

 

[newguy]

Use the the TextChanged event:

Private Sub TextBox2_TextChanged(ByVal sender As Object, ByVal e As EventArgs) Handles Textbox2.TextChanged
  Try
   If Not String.IsNullOrEmpty(Textbox1.Text) Then
      If Textbox2.Text.Length > 0 Then
         TextBox3.Text = Cint(Textbox1.Text) + Cint(Textbox2.Text)
      Else
         TextBox3.Text = String.Empty
      End If
   End If
  Catch
  End Try
End Sub

Also consider using the keypress to capture only number keystrokes, or errors you'll throw...

 

[newguy]

Personally, I would use a label in-place of textbox3, they won't need to edit this, it just holds the result.

 

[LeonR]

Personally, I would use a label in-place of textbox3, they won't need to edit this, it just holds the result.

They may want to copy it though (just a thought).