How do I set the keyboard shortcut character for a Windows Forms button with no text?

Question

I have a Windows Forms app with some buttons with images but no text. Normally for a button, the shortcut is specified with the ampersand character (&). But what does one do when there's no text?

I know there are tricks, such as leading spaces to push the text off to the right or down. Or play with the font, forecolor, etc. But I don't like such tricks because they sometimes backfire.

Should I consider handling the shortcuts for all controls through the Key events of the form? How would this sort out which control is selected? Are form Key events filtered through the form before they're sent on to the Key events of the controls? I'm not sure what to do if I went this way.

Here is a [sample](https://stackoverflow.com/a/10470974/5509738) for ProcessCmdKey — Karen Payne, Oct 19 '22 at 21:10

Jimi · Answer 1 · 2022-10-20T06:19:27.260

Should I consider handling the shortcuts for all controls through the Key events of the Form?

You sure can, overriding ProcessCmdKey() in your Form(s). As you can read in the docs, it's kind of made for this (to provide additional handling of main menu command keys and MDI accelerators)

To associate a Button to a bitwise combination of Keys (the Windows Forms Keys enumerator is decorated with the [Flags] attribute), you can use a map, often a Dictionary that associates a Key to something else.
In this case, it could be a Button Control or an Action. For example:

private Dictionary<Keys, Button> accelerators = null;   

protected override void OnLoad(EventArgs e) {
    accelerators = new Dictionary<Keys, Button>() {
        [Keys.Alt | Keys.A] = someButton,
        [Keys.Alt | Keys.Control | Keys.B] = otherButton
    };
    base.OnLoad(e);
}

In the ProcessCmdKey override, test whether the map (Dictionary) contains the combination of keys pressed and raise the Click event of the associated Button if it's a match:

protected override bool ProcessCmdKey(ref Message msg, Keys keyData)
{
    if (accelerators.ContainsKey(keyData)) {
        accelerators[keyData].PerformClick();
        return true;
    }
    return base.ProcessCmdKey(ref msg, keyData);
}

VB.Net version (since it's tagged):

Private accelerators As Dictionary(Of Keys, Button) = Nothing

Protected Overrides Sub OnLoad(e As EventArgs)
    accelerators = New Dictionary(Of Keys, Button)() From {
        {Keys.Alt Or Keys.A, someButton},
        {Keys.Alt Or Keys.Control Or Keys.B, otherButton}
    }
    MyBase.OnLoad(e)
End Sub

Protected Overrides Function ProcessCmdKey(ByRef msg As Message, keyData As Keys) As Boolean
    If accelerators.ContainsKey(keyData) Then
        accelerators(keyData).PerformClick()
        Return True
    End If

    Return MyBase.ProcessCmdKey(msg, keyData)
End Function

Yes, my app is VB, but I tagged C# too because Winforms applies to both. I saw all your comments last night but didn't reply because I was tired & went to bed. I also saw where you said you'd already answered six questions that day. Thank you for taking the time to write your comments into an answer. I really appreciate it. I'll try this in my app and see what happens. — spinjector, Oct 20 '22 at 20:49

Henry · Answer 2 · 2022-10-21T10:28:31.110

This is how I do it.

set the KeyPreview to true for the form to capture keys.

then check the keys on KeyDown event on the form and trigger button1.PerformClick();

 public Form1()
    {
        InitializeComponent();
        KeyPreview = true;
    }

    private void button1_Click(object sender, EventArgs e)
    {
        MessageBox.Show("you pressed Ctrl + S");
    }

    private void Form1_KeyDown(object sender, KeyEventArgs e)
    {
        if (e.Control && e.KeyCode == Keys.S)
        {
            button1.PerformClick();
        }
    }

score 0 · Answer 3 · answered Oct 21 '22 at 06:36

Hope this can help you.

Set your Form KeyPreview Property to true.
Subscribe to the KeyDown Event of the Form as below:

this.KeyDown += new System.Windows.Forms.KeyEventHandler(this.Form1_KeyDown);

Handle the KeyDown event of Form as below:

 private void Form1_KeyDown(object sender, KeyEventArgs e)
 {
     if (e.Control  && e.KeyCode == Keys.S)
         MessageBox.Show("Ctrl + S pressed!");
 }

Complete Code:

this.KeyDown += new System.Windows.Forms.KeyEventHandler(this.Form1_KeyDown);
private void Form1_KeyDown(object sender, KeyEventArgs e)
{
     if (e.Control  &&  e.KeyCode == Keys.S)
       MessageBox.Show("Ctrl + S pressed!");
}

How do I set the keyboard shortcut character for a Windows Forms button with no text?

3 Answers3