C# 控制 Windows 中程式視窗大小與位置

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Introduction

通常程式預設起始位置為視窗正中間，但有時因為手殘動到導致視窗歪了、不在正中間了，身為強迫症患者就會越看越賭爛。因此本篇將記錄一下，利用 C# 來控制 Windows 中其他應用程式的視窗大小與位置。

Supports

Windows 7sp1/8/8.1/10 with .NET Framework 4.6.1 (or higher)

Code

以下程式將示範透過應用程式標題名稱取得該視窗，並設定視窗位置為左右垂直置中。

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using System;
using System.Runtime.InteropServices;
using System.Windows.Forms;

namespace ConsoleApp1
{
    class Program
    {
        // Define the FindWindow API function.
        [DllImport("user32.dll", EntryPoint = "FindWindow", SetLastError = true)]
        static extern IntPtr FindWindowByCaption(IntPtr ZeroOnly, string lpWindowName);

        // Define the SetWindowPos API function.
        [DllImport("user32.dll")]
        [return: MarshalAs(UnmanagedType.Bool)]
        static extern bool SetWindowPos(IntPtr hWnd, IntPtr hWndInsertAfter, int X, int Y, int cx, int cy, SetWindowPosFlags uFlags);

        // Define the SetWindowPosFlags enumeration.
        [Flags()]
        private enum SetWindowPosFlags : uint
        {
            SynchronousWindowPosition = 0x4000,
            DeferErase = 0x2000,
            DrawFrame = 0x0020,
            FrameChanged = 0x0020,
            HideWindow = 0x0080,
            DoNotActivate = 0x0010,
            DoNotCopyBits = 0x0100,
            IgnoreMove = 0x0002,
            DoNotChangeOwnerZOrder = 0x0200,
            DoNotRedraw = 0x0008,
            DoNotReposition = 0x0200,
            DoNotSendChangingEvent = 0x0400,
            IgnoreResize = 0x0001,
            IgnoreZOrder = 0x0004,
            ShowWindow = 0x0040,
        }

        static void Main(string[] args)
        {
            // Get the target window's handle by caption.
            IntPtr target_hwnd = FindWindowByCaption(IntPtr.Zero, "Visual Studio");

            // If got the window.
            if (target_hwnd != IntPtr.Zero)
            {
                int width = "<your window's width>";
                int height = "<your window's height>";
                int x = (Screen.PrimaryScreen.WorkingArea.Width - width) / 2;
                int y = (Screen.PrimaryScreen.WorkingArea.Height - height) / 2;
                SetWindowPos(target_hwnd, IntPtr.Zero, x, y, width, height, 0);
            }
        }
    }
}

若不知道或不確定該視窗標題，可透過以下程式來列表出所有視窗標題來取得：

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foreach (var process in System.Diagnostics.Process.GetProcesses())
    if (!string.IsNullOrEmpty(process.MainWindowTitle))
        Console.WriteLine($"Process: {process.ProcessName}\tID: {process.Id}\tWindow title: {process.MainWindowTitle}");

References