在C#中獲取窗口句柄可以使用FindWindow函數或Process.MainWindowHandle屬性。

1. 使用FindWindow函數：

using System;
using System.Runtime.InteropServices;

class Program
{
    [DllImport("user32.dll", SetLastError = true)]
    static extern IntPtr FindWindow(string lpClassName, string lpWindowName);

    static void Main()
    {
        IntPtr handle = FindWindow(null, "Window Title");
        if (handle != IntPtr.Zero)
        {
            Console.WriteLine("Window handle: " + handle);
        }
        else
        {
            Console.WriteLine("Window not found.");
        }
    }
}

2. 使用Process.MainWindowHandle屬性：

using System;
using System.Diagnostics;

class Program
{
    static void Main()
    {
        Process[] processes = Process.GetProcessesByName("ProcessName");
        foreach (Process process in processes)
        {
            IntPtr handle = process.MainWindowHandle;
            if (handle != IntPtr.Zero)
            {
                Console.WriteLine("Window handle: " + handle);
            }
            else
            {
                Console.WriteLine("Window not found for process: " + process.ProcessName);
            }
        }
    }
}

請注意替換"Window Title"和"ProcessName"為你要查找的窗口標題和進程名稱。