Trying to create Keypad for VB.Net Application

Question

I am working on creating a keypad for a VB.Net Application I am working on. The Keypad's purpose is to help users who are using the app on a touchpad station that does not have a mouse or keyboard.

This is the code I have used to set up the Keypad:

Public Class Keypad

    Private Sub Keypad_Load(sender As Object, e As Event Args) Handles MyBase.Load
        Me.TopMost = True
    End Sub

    Protected Overrides ReadOnly Property CreateParams As CreateParams
        Get
            Const WS_EX_NOACTIVATE As Int32 = &H8000000
            Dim cp As CreateParams = MyBase.CreateParams
            cp.ExStyle = cp.ExStyle Or WS_EX_NOACTIVATE
            Return cp
        End Get
    End Property

    Private Sub btn0_Click(sender As Object, e As EventArgs) Handles btn0.Click
        SendKeys.Send("0")
    End Sub

    Private Sub btn1_Click(sender As Object, e As EventArgs) Handles btn1.Click
        SendKeys.Send("0")
    End Sub

    'all other button methods are the same as above

So the Keypad itself is a simply setup. Standard Numpad 1-9 layout, as well as a 'Clear' and 'Enter' button.

I am currently having the following problems with the Keypad:

1. While in the VB.Net I have created the Keypad for, attempting to use the Keypad does nothing. However if I open Notepad and have given focus to Notepad, using the Keypad will type numbers into Notepad.

2. The Login Screen for the Application is setup as a Dialogue Window, and I am unable to modify that (legacy code issues). This means the Keypad is both unmovable, and unusable while the Login Screen is open.

3. The 'Clear' Button is suppose to remove all data in whatever form element has focus when the button is selected. However, I am not exactly sure how to program this, and how to make it so that it doesn't completely bug out the Keypad if the user has a non VB.Net application focused when the key is pressed.

EDIT: After doing some testing, it turns out the Keypad works fine if I set it up as a completely separate Project. So it turns out the issue seems to be the Keypad Form being part of the initial project I was creating it for.

Answer 1

This is a solution that doesn't use SendKeys. No worries about Focus. Instead I send the TextBox that is to receive the input to a field in the KeyPad. Now the KeyPad form knows where to send the input. I have assigned one handler to all the keyPad buttons. The cast sender back to Button and use the .Text property of the button.

Public Class KeyPad
    Public TextOutputControl As TextBox
    Private Sub KeyPad_Click(sender As Object, e As EventArgs) Handles Button1.Click, Button2.Click, Button3.Click
        Dim ClickedAmount As String = DirectCast(sender, Button).Text
        TextOutputControl.Text &= ClickedAmount
    End Sub
End Class

The on each form that wants to use the keypad...

Private Sub btnShowKeyPad_Click(sender As Object, e As EventArgs) Handles btnShowKeyPad.Click
    KeyPad.Show()
    KeyPad.TextOutputControl = TextBox1
End Sub

Of course the TextBox can have any name you wish.

EDIT

To use with a DataGridView cell change the data type of TextOutputControl to Object. You will need to check what type of object was passed in and send the data back accordingly.

Public Class KeyPad
    Public TextOutputControl As Object
    Private Sub KeyPad_Click(sender As Object, e As EventArgs) Handles Button1.Click, Button2.Click, Button3.Click
        Dim ClickedAmount As String = DirectCast(sender, Button).Text
        Dim t As Type = TextOutputControl.GetType
        Dim tTexBox As Type = GetType(TextBox)
        If t.Equals(GetType(TextBox)) Then
            DirectCast(TextOutputControl, TextBox).Text &= ClickedAmount
        Else
            Dim s = CStr(DirectCast(TextOutputControl, DataGridViewCell).Value)
            s &= ClickedAmount
            DirectCast(TextOutputControl, DataGridViewCell).Value = s
        End If
    End Sub
End Class

Then in the form with the DataGridView...

Private Sub btnShowKeyPad_Click(sender As Object, e As EventArgs) Handles btnShowKeyPad.Click
    KeyPad.Show()
    'KeyPad.TextOutputControl = TextBox1
    KeyPad.TextOutputControl = DataGridView1.CurrentCell
End Sub