How to add placeholder text to ToolStripTextBox?

Question

In a WinForms project, I know how to add placeholder text to a regular textbox. But the ToolStripTextBox doesn't appear to be a regular textbox. For one, it doesn't expose the handle (which is what's required to set the placeholder text via Win API).

So, how do I either set the placeholder text on a ToolStripTextBox or get its .Handle property?

Reza Aghaei · Accepted Answer · 2018-06-19T03:36:20.847

ToolStripTextBox hosts a ToolStripTextBoxControl inside which is derived from TextBox and you can access the the hosted control using its TextBox or its Control property. So you can write such code:

using System;
using System.Drawing;
using System.Runtime.InteropServices;
using System.Windows.Forms;

[ToolboxBitmap(typeof(ToolStripTextBox))]
public class MyToolStripTextBox : ToolStripTextBox
{
    private const int EM_SETCUEBANNER = 0x1501;
    [DllImport("user32.dll", CharSet = CharSet.Auto)]
    private static extern Int32 SendMessage(IntPtr hWnd, int msg,
        int wParam, string lParam);
    public MyToolStripTextBox()
    {
        this.Control.HandleCreated += Control_HandleCreated;
    }
    private void Control_HandleCreated(object sender, EventArgs e)
    {
        if (!string.IsNullOrEmpty(cueBanner))
            UpdateCueBanner();
    }
    string cueBanner;
    public string CueBanner
    {
        get { return cueBanner; }
        set
        {
            cueBanner = value;
            UpdateCueBanner();
        }
    }
    private void UpdateCueBanner()
    {
        SendMessage(this.Control.Handle, EM_SETCUEBANNER, 0, cueBanner);
    }
}

Also for a `TextBox`, you can refer to [this post](https://stackoverflow.com/a/4902969/3110834) or [this one](https://stackoverflow.com/a/36534068/3110834). — Reza Aghaei, Jun 19 '18 at 03:21
Thanks for the solution. Since it is not so easy (or I did not find an easy way to do) to replace the inner control, you can also use the SendMessage approach from outside: _ = NativeMethods.SendMessage(tstbSearch.TextBox.Handle, NativeMethods.EM_SETCUEBANNER, 0, "Find..."); — TomB, Mar 03 '22 at 11:28
@TomB of course you can. What I've done in this post is creating a ready to use MyToolStripTextBox so that you can have the feature in design-time as well. — Reza Aghaei, Mar 03 '22 at 11:38

score 1 · Answer 2 · answered Jun 19 '18 at 02:37

Have not tried myself.

But the Remarks section indicates you can manipulate the TextBox control directly.

ToolStripTextBox is the TextBox optimized for hosting in a ToolStrip. A subset of the hosted control's properties and events are exposed at the ToolStripTextBox level, but the underlying TextBox control is fully accessible through the TextBox property.

How to add placeholder text to ToolStripTextBox?

2 Answers2

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