Button inside a WinForms textbox

Question

Do WinForms textboxes have any properties that make an embedded button, at the end of the box, possible?

Something like the favorites button on the Chrome address bo

Answer 1

Getting the button inside the TextBox just requires adding it to the box' Controls collection. You'll also need to do something reasonable to prevent the text inside the box disappearing underneath the button; that requires a wee bit of pinvoke. Like this:

    protected override void OnLoad(EventArgs e) {
        var btn = new Button();
        btn.Size = new Size(25, textBox1.ClientSize.Height + 2);
        btn.Location = new Point(textBox1.ClientSize.Width - btn.Width, -1);
        btn.Cursor = Cursors.Default;
        btn.Image = Properties.Resources.star;
        textBox1.Controls.Add(btn);
        // Send EM_SETMARGINS to prevent text from disappearing underneath the button
        SendMessage(textBox1.Handle, 0xd3, (IntPtr)2, (IntPtr)(btn.Width << 16));
        base.OnLoad(e);  
    }

    [System.Runtime.InteropServices.DllImport("user32.dll")]
    private static extern IntPtr SendMessage(IntPtr hWnd, int msg, IntPtr wp, IntPtr lp);

Looked like this while I tested the right margin (should have picked a prettier bitmap):