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Keydown

    Question

  • I need a good description on how to do a keydown event in visual basic 8... please make a keydown event code on the letter "a" and "enter". Thanks a lot.
    Tuesday, February 06, 2007 11:06 PM

Answers

  • derek42092,

    The KeyDown event occurs when a key is pressed while the control has focus. The following code example uses the KeyDown event to determine the type of character entered into the control.

        ' Boolean flag used to determine when a character other than a number is entered.

        Private nonNumberEntered As Boolean = False

     

     

        ' Handle the KeyDown event to determine the type of character entered into the control.

        Private Sub textBox1_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) _

             Handles textBox1.KeyDown

            ' Initialize the flag to false.

            nonNumberEntered = False

     

            ' Determine whether the keystroke is a number from the top of the keyboard.

            If e.KeyCode < Keys.D0 OrElse e.KeyCode > Keys.D9 Then

                ' Determine whether the keystroke is a number from the keypad.

                If e.KeyCode < Keys.NumPad0 OrElse e.KeyCode > Keys.NumPad9 Then

                    ' Determine whether the keystroke is a backspace.

                    If e.KeyCode <> Keys.Back Then

                        ' A non-numerical keystroke was pressed.

                        ' Set the flag to true and evaluate in KeyPress event.

                        nonNumberEntered = True

                    End If

                End If

            End If

        End Sub 'textBox1_KeyDown

     

     

        ' This event occurs after the KeyDown event and can be used

        ' to prevent characters from entering the control.

        Private Sub textBox1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) _

            Handles textBox1.KeyPress

            ' Check for the flag being set in the KeyDown event.

            If nonNumberEntered = True Then

                ' Stop the character from being entered into the control since it is non-numerical.

                e.Handled = True

            End If

        End Sub 'textBox1_KeyPress

    End Class 'Form1

     

     

    Thursday, February 08, 2007 7:05 AM