C# 两个API函数.[关于插入光标]

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Runtime.InteropServices; //调用API,需要引用这个命名空间

namespace WindowsFormsApplication2
{
public partial class Form1 : Form
{

/// <summary>
/// 两个API函数,其作用是:指定窗口的指定位置插入插入符.
/// </summary>
/// <param name="hwnd">窗口句柄</param>
/// <param name="hBitmap">插入符的样式,可以为NULL</param>
/// <param name="nWidth">插入符的宽度</param>
/// <param name="nHeight">插入符的高度</param>
/// <returns></returns>

[DllImport("user32.dll", EntryPoint = "CreateCaret")]
static extern int CreateCaret(IntPtr hwnd, int hBitmap, int nWidth, int nHeight);

/// <summary>
/// 显示插入符
/// </summary>
/// <param name="hWnd">窗口句柄</param>
/// <returns></returns>
[DllImport("user32.dll", EntryPoint = "ShowCaret")]
static extern bool ShowCaret(IntPtr hWnd);

public Form1()
{
InitializeComponent();
}

private void button2_Click(object sender, EventArgs e)
{
CreateCaret(this.Handle, 1, 20, 40);
ShowCaret(this.Handle);

}

}

}