using System.Runtime.InteropServices;

// Get a handle to an application window.

[DllImport("USER32.DLL", CharSet = CharSet.Unicode)]

public static extern IntPtr FindWindow(string lpClassName,

string lpWindowName);

// Activate an application window.

[DllImport("USER32.DLL")]

public static extern bool SetForegroundWindow(IntPtr hWnd);

//FindWindow 参数一是进程名 参数2是 标题名

IntPtr calculatorHandle = FindWindow(null, "计算器");

//判断是否找到

if (calculatorHandle == IntPtr.Zero)

{

MessageBox.Show("没有找到!");

return;

}

// 然后使用SetForegroundWindow函数将这个窗口调到最前。

SetForegroundWindow(calculatorHandle);

//发送按键

SendKeys.SendWait("");

SendKeys.SendWait("*");

SendKeys.SendWait("");

SendKeys.SendWait("=");