Non-restricted movement between buttons

[Anderskd1]

Hi there

I am creating a Windows Forms App .NET with VB in VS, and I have 4 buttons arranged in a square (2 rows and 2 columns).
I would like to have free movement between the buttons using the arrow keys, so that when the upper left button has focus
I can move focus to the lower left button with the down arrow, or to the upper right button using the right arrow.

I already sat the focus to be on the upper left button when the form is shown, and I have tinkered a little bit with the
TabIndex and the TabStop, but can't seem to get 100% free movement.

Also, I have tried using a KeyDown event on the button, like this:

If e.KeyCode = Keys.Down Then
Button4.Focus()
End if

But it does not work...

Any ideas?
Thanks!

[.paul.]

Try this...

Public Class Form20

    Dim buttons(1)() As Button

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        buttons(0) = New Button() {Button1, Button2}
        buttons(1) = New Button() {Button3, Button4}        
    End Sub

    Protected Overrides Function ProcessCmdKey(ByRef msg As System.Windows.Forms.Message, ByVal keyData As System.Windows.Forms.Keys) As Boolean
        Dim sy As Integer
        Dim sx As Integer
        sx = Array.IndexOf(buttons(0), Control.FromHandle(msg.HWnd))
        If sx > -1 Then
            sy = 0
        Else
            sy = 1
            sx = Array.IndexOf(buttons(1), Control.FromHandle(msg.HWnd))
        End If

        Select Case keyData
            Case Keys.Up
                If sx = -1 then Return False
                If sy = 1 Then
                    buttons(0)(sx).Select()
                End If
                Return True
            Case Keys.Down
                If sy = 0 Then
                    buttons(1)(sx).Select()
                End If
                Return True
            Case Keys.Left
                If sx = 1 Then
                    buttons(sy)(0).Select()
                End If
                Return True
            Case Keys.Right
                If sx = 0 Then
                    buttons(sy)(1).Select()
                End If
                Return True
        End Select

        Return False

End Class

[Anderskd1]

Thank you for your reply, I will try it in a moment

And if I had 9 buttons also in a square (3x3) it would just be this?:

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
buttons(0) = New Button() {Button1, Button2, Button3}
buttons(1) = New Button() {Button4, Button5, Button6}
buttons(2) = New Button() {Button7, Button8, Button9}
End Sub

And then change the rest accordingly?

[.paul.]

Thank you for your reply, I will try it in a moment

And if I had 9 buttons also in a square (3x3) it would just be this?:

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
buttons(0) = New Button() {Button1, Button2, Button3}
buttons(1) = New Button() {Button4, Button5, Button6}
buttons(2) = New Button() {Button7, Button8, Button9}
End Sub

And then change the rest accordingly?

There would be more to do than just changing the array

[Anderskd1]

Would you be so kind to explain the rest of the changes if ther were 3x3 buttons, please?
I'm just not sure that I understand the "sx" and "sy" part.

[.paul.]

Imagine a square grid with 3 rows and 3 columns
sx is the horizontal index of a cell
sy is the vertical index of a cell

Now you can see that the array is a square grid of 3 rows of 3 buttons

[Anderskd1]

Ah, okay, that makes a lot of sense, but what is up with the "-1"?

[.paul.]

Here's a 3 by 3 grid of buttons...

Public Class Form1

    Dim buttons(2)() As Button

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        buttons(0) = New Button() {Button1, Button2, Button3}
        buttons(1) = New Button() {Button4, Button5, Button6}
        buttons(2) = New Button() {Button7, Button8, Button9}
    End Sub

    Protected Overrides Function ProcessCmdKey(ByRef msg As System.Windows.Forms.Message, ByVal keyData As System.Windows.Forms.Keys) As Boolean
        Dim sy As Integer = -1
        Dim sx As Integer = -1
        sx = Array.IndexOf(buttons(0), Control.FromHandle(msg.HWnd))
        If sx > -1 Then
            sy = 0
        Else
            sx = Array.IndexOf(buttons(1), Control.FromHandle(msg.HWnd))
            If sx > -1 Then
                sy = 1
            Else
                sx = Array.IndexOf(buttons(2), Control.FromHandle(msg.HWnd))
                If sx > -1 Then
                    sy = 2
                Else
                    sy = -1
                End If
            End If
        End If

        Select Case keyData
            Case Keys.Up
                If sy = 1 Then
                    buttons(0)(sx).Select()
                End If
                If sy = 2 Then
                    buttons(1)(sx).Select()
                End If
                Return True
            Case Keys.Down
                If sy = 0 Then
                    buttons(1)(sx).Select()
                End If
                If sy = 1 Then
                    buttons(2)(sx).Select()
                End If
                Return True
            Case Keys.Left
                If sx = 1 Then
                    buttons(sy)(0).Select()
                End If
                If sx = 2 Then
                    buttons(sy)(1).Select()
                End If
                Return True
            Case Keys.Right
                If sx = 0 Then
                    buttons(sy)(1).Select()
                End If
                If sx = 1 Then
                    buttons(sy)(2).Select()
                End If
                Return True
        End Select

        Return False

    End Function
End Class

The Array.IndexOf function, either finds the index of what you specify, or -1 if it can't find it...

[.paul.]

Control.FromHandle(msg.HWnd) is the Button (or any control on your form) that has the focus when the CMD key is pressed

[.paul.]

To avoid blocking arrow key navigation on other controls on your form, such as ListBoxes, or DataGridViews...

Protected Overrides Function ProcessCmdKey(ByRef msg As System.Windows.Forms.Message, ByVal keyData As System.Windows.Forms.Keys) As Boolean
    Dim sy As Integer = -1
    Dim sx As Integer = -1
    sx = Array.IndexOf(buttons(0), Control.FromHandle(msg.HWnd))
    If sx > -1 Then
        sy = 0
    Else
        sx = Array.IndexOf(buttons(1), Control.FromHandle(msg.HWnd))
        If sx > -1 Then
            sy = 1
        Else
            sx = Array.IndexOf(buttons(2), Control.FromHandle(msg.HWnd))
            If sx > -1 Then
                sy = 2
            Else
                sy = -1
            End If
        End If
    End If

    Select Case keyData
        Case Keys.Up
            If sy = -1 Then Return False
            If sy = 1 Then
                buttons(0)(sx).Select()
            End If
            If sy = 2 Then
                buttons(1)(sx).Select()
            End If
            Return True
        Case Keys.Down
            If sy = -1 Then Return False
            If sy = 0 Then
                buttons(1)(sx).Select()
            End If
            If sy = 1 Then
                buttons(2)(sx).Select()
            End If
            Return True
        Case Keys.Left
            If sx = -1 Then Return False
            If sx = 1 Then
                buttons(sy)(0).Select()
            End If
            If sx = 2 Then
                buttons(sy)(1).Select()
            End If
            Return True
        Case Keys.Right
            If sx = -1 Then Return False
            If sx = 0 Then
                buttons(sy)(1).Select()
            End If
            If sx = 1 Then
                buttons(sy)(2).Select()
            End If
            Return True
    End Select

    Return False

End Function

[Anderskd1]

Wow thank you very much for your help! I really appreciate it.
I will try it out tomorrow

[Anderskd1]

It worked! Thank you very much, Paul!