[RESOLVED] Capture key press for hotkey

Hello, I'm making an application that will execute some functions on user defined key presses.

The user needs to set the keys they want to fire the function in a textbox. I've set the textbox to Read-Only and am trying to make the code that will specify the key combinations used that are displayed in the textbox. So for example; if a user presses Ctrl + Alt + Shift + E, the textbox will show this.

I'm using the KeyDown and KeyUp events that come with a textbox. The textbox will loose focus once a control key (Ctrl or Alt) AND an alphanumeric key (such as E) is pressed. Shift is optional.

I need to store this data, so that it can later be fed into the GetAsyncKeyState function that will listen in a timer.

I'm having some troubles getting the KeyDown and KeyUp detect whether is was the left or right Ctrl, Alt and Shift keys pressed as well.

Here's my code currently:

Code:

---

    Private ctrlKeyDw As Boolean = False
    Private altKeyDw As Boolean = False
    Private shiftKeyDw As Boolean = False

    Private Sub txtCaptureKey_KeyDown(sender As Object, e As KeyEventArgs) Handles txtCaptureKey.KeyDown

        If e.KeyCode = Keys.ControlKey Then
            ctrlKeyDw = True
        End If

        If e.KeyCode = Keys.Alt Then
            altKeyDw = True
        End If

        If e.KeyCode = Keys.Shift Then
            shiftKeyDw = True
        End If

        updateText()

    End Sub

    Private Sub updateText()

        txtCaptureKey.Text = ""

        If ctrlKeyDw Then
            txtCaptureKey.Text = "Ctrl + " & txtCaptureKey.Text
        End If

        If altKeyDw Then
            txtCaptureKey.Text = "Alt + " & txtCaptureKey.Text
        End If

        If shiftKeyDw Then
            txtCaptureKey.Text = "Shift + " & txtCaptureKey.Text
        End If

        If txtCaptureKey.Text = "" Then
            txtCaptureKey.Text = "None"
        End If

    End Sub

    Private Sub txtCaptureKey_KeyUp(sender As Object, e As KeyEventArgs) Handles txtCaptureKey.KeyUp

        If e.KeyCode = Keys.ControlKey Then
            ctrlKeyDw = False
        End If

        If e.KeyCode = Keys.Alt Then
            altKeyDw = False
        End If

        If e.KeyCode = Keys.Shift Then
            shiftKeyDw = False
        End If

        updateText()

    End Sub

---

At the moment it's only detecting when Ctrl is pressed. I can't figure out why Shift and Alt are not being detected.

Don't the KeyCode property to detect modifier keys in combination with other keys.

vb.net Code:

Private Sub TextBox1_KeyDown(sender As Object, e As KeyEventArgs) Handles TextBox1.KeyDown
    Dim depressedKeys As New List(Of String)
 
    If e.Control Then
        depressedKeys.Add("Ctrl")
    End If
 
    If e.Shift Then
        depressedKeys.Add("Shift")
    End If
 
    If e.Alt Then
        depressedKeys.Add("Alt")
    End If
 
    If e.KeyCode >= Keys.A AndAlso e.KeyCode <= Keys.Z Then
        depressedKeys.Add(e.KeyCode.ToString())
    End If
 
    Me.TextBox1.Text = String.Join("+", depressedKeys)
End Sub

Thanks heaps for that jmcilhinney. Is there any reason that Lcontrol and RControl doesn't work when using KeyCode? Otherwise your code is working perfectly.

Quote:

---

Originally Posted by Slyke

Thanks heaps for that jmcilhinney. Is there any reason that Lcontrol and RControl doesn't work when using KeyCode? Otherwise your code is working perfectly.

---

As far as I can tell from research on the web and my own testing, you can't detect the difference between the left and right Ctrl keys via Windows Forms keyboard events. I haven't checked but I'm guessing that the same is true of Shift and Alt keys. You would have to first detect a Ctrl key in the conventional way and then use the GetAsyncKeyState API to determine the state of the left and right keys.

That's a great idea. Will do just that.