How do I capture the enter key in a windows forms combobox

Question

How do I capture the enter key in a windows forms combo box when the combobox is active?

I've tried to listen to KeyDown and KeyPress and I've created a subclass and overridden ProcessDialogKey, but nothing seems to work.

Any ideas?

/P

Solution 1

Hook up the KeyPress event to a method like this:

protected void myCombo_OnKeyPress(object sender, KeyPressEventArgs e)
{
    if (e.KeyChar == 13)
    {
        MessageBox.Show("Enter pressed", "Attention");                
    }
}

I've tested this in a WinForms application with VS2008 and it works.

If it isn't working for you, please post your code.

Solution 2

In case you define AcceptButton on your form, you cannot listen to Enter key in KeyDown/KeyUp/KeyPress.

In order to check for that, you need to override ProcessCmdKey on FORM:

protected override bool ProcessCmdKey(ref Message msg, Keys keyData) {
    if ((this.ActiveControl == myComboBox) && (keyData == Keys.Return)) {
        MessageBox.Show("Combo Enter");
        return true;
    } else {
        return base.ProcessCmdKey(ref msg, keyData);
    }
}

In this example that would give you message box if you are on combo box and it works as before for all other controls.

Solution 3

or altertatively you can hook up the KeyDown event:

private void comboBox1_KeyDown(object sender, KeyEventArgs e)
{
    if (e.KeyCode == Keys.Enter)
    {
        MessageBox.Show("Enter pressed.");
    }
}

Solution 4

private void comboBox1_KeyDown( object sender, EventArgs e )
{
   if( e.KeyCode == Keys.Enter )
   {
      // Do something here...
   } else Application.DoEvents();
}

Solution 5

Try this:

protected override bool ProcessCmdKey(ref Message msg, Keys k)
{
    if (k == Keys.Enter || k == Keys.Return)
    {
        this.Text = null;
        return true;
    }

    return base.ProcessCmdKey(ref msg, k);
}

View more solutions

Comments

[user1576301]

I've already tried it. It does not work. Try it your self and see. Thats why I posted the question.

[Warpspace]

One possible reason would be that some other event handler catches the enter first and stops the rest of the handlers do their job. For example a Menu or the form itself.

[user1576301]

You are right. ...it does work when I isolated the code to make it "postable", so the error must lie somewhere else. I'll try searching with Petros hint. Thanks guys.

[Phil Lambert]

if (e.KeyChar == (char)Keys.Enter) { }

[Shereef Marzouk]

there is a property on the form that is called KeyPreview, enable it i guess