windows API 最大化窗体

这个是个入门问题，很奇怪为什么网上的回答那么213，自己写一个

private void button3_Click(object sender, EventArgs e)
{

IntPtr ParenthWnd = new IntPtr(0);

ParenthWnd = FindWindow(null, "电话服务平台1.01 - [欢迎使用]");

if (!ParenthWnd.Equals(IntPtr.Zero))
{
// SendMessage(WM_SYSCOMMAND, SC_RESTORE, MAKELPARAM(point.x, point.y));

ShowWindow(ParenthWnd, SW_SHOWMINIMIZED);
SendMessage(ParenthWnd, WM_SYSCOMMAND, (IntPtr)SC_MAXIMIZE, "");
// SendMessage(ParenthWnd, SC_MAXIMIZE, (IntPtr)0, "0");
// Thread.Sleep(100);

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const int SW_SHOWMINIMIZED = 2;

const int WM_SYSCOMMAND = 0x0112;
const int SC_MAXIMIZE = 0xF030;

[DllImport("User32.dll", EntryPoint = "SendMessage")]
private static extern int SendMessage(IntPtr hWnd, int Msg, IntPtr wParam, string lParam);

[DllImport("user32.dll")]
private static extern bool ShowWindow(IntPtr hWnd, int nCmdShow);