Windows forms: how to do a thick blinking cursor on a textbox?

Question

I am rewriting a windows forms application (updated framework, rewrote the logic, etc.) and there is one thing that I just can't figure out how they did. Textboxes in the original application had a thick blinking cursor like so: http://screencast.com/t/8QYUcjuh3n

For the life of me I can't figure how to do this. Please help?

Answer 1

You can do it with pinvoke CreateCaret

The example uses a Winform with a button (button1) and textbox (textBox1).

Add this using directive:

using System.Runtime.InteropServices;

Add these declarations:

[DllImport("user32.dll")]
static extern bool CreateCaret(IntPtr hWnd, IntPtr hBitmap, int nWidth, int nHeight);
[DllImport("user32.dll")]
static extern bool ShowCaret(IntPtr hWnd);

Add this code to the button click event:

  // Thickness is set where I have 10.
  CreateCaret(textBox1.Handle, IntPtr.Zero, 10, textBox1.Height);
  ShowCaret(textBox1.Handle);

When you click the button you'll get a thicker cursor.

There's also a discussion of this here.