1、命名空间：

using System.Runtime.InteropServices;

2、导入方法

[DllImport("user32.dll", EntryPoint = "GetKeyboardState")]

public static extern int GetKeyboardState(byte[] pbKeyState);

3、大小写状态

public static bool CapsLockStatus

{

get

{

byte[] bs = new byte[256];

GetKeyboardState(bs);

return (bs[0x14] == 1);

}

}

4、引用，此部分根据你的需要来修改

private void button2_Click(object sender, EventArgs e)

{

if (CapsLockStatus == true)

MessageBox.Show("键盘处于大写锁定状态！");

else

MessageBox.Show("键盘处于小写状态！");

}