将过程句柄窗口位置设置为屏幕中心时，它可以工作，但在所有情况下都不是为什么？

Question

In form1 if the process is not yet running then run it bring it to front and center it to the screen center. If the process already running only bring it to front and center it:

if (AutoIt.AutoItX.WinExists(existingProcessName, "") == 0) // Window not found
            {
                int processId = AutoIt.AutoItX.Run(processFileName, "", AutoIt.AutoItX.SW_SHOW);
                SetProcessWindow.BringToFront(processId);
                SetProcessWindow.CenterProcessWindow(processId);
                Thread.Sleep(10000);
                AutoIt.AutoItX.MouseClick("LEFT", 358, 913, 1, -1);

            }
            else
            {
                Process[] processes = Process.GetProcessesByName(processName);
                SetProcessWindow. BringToFront(processes[0].Id);
                SetProcessWindow.CenterProcessWindow(processes[0].Id);
                Thread.Sleep(10000);
                AutoIt.AutoItX.MouseClick("LEFT", 358, 913, 1, -1);
            }

And the class SetProcessWindow:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Runtime.InteropServices;
using System.Diagnostics;
using System.Windows.Forms;
using System.Drawing;

namespace UsingAutoIt
{
    class SetProcessWindow
    {
        [DllImport("USER32.DLL")]
        public static extern bool SetForegroundWindow(IntPtr hWnd);

        [DllImport("user32.dll")]
        [return: MarshalAs(UnmanagedType.Bool)]
        static extern bool GetWindowRect(IntPtr hWnd, out RECT lpRect);

        [StructLayout(LayoutKind.Sequential)]
        public struct RECT
        {
            public int Left;        // x position of upper-left corner
            public int Top;         // y position of upper-left corner
            public int Right;       // x position of lower-right corner
            public int Bottom;      // y position of lower-right corner
        }

        private const int SWP_NOSIZE = 0x0001;
        private const int SWP_NOZORDER = 0x0004;
        private const int SWP_SHOWWINDOW = 0x0040;

        [DllImport("user32.dll", SetLastError = true)]
        static extern bool SetWindowPos(IntPtr hWnd, IntPtr hWndInsertAfter, int X, int Y, int cx, int cy, int uFlags);

        public static void BringToFront(int processId)
        {
            Process process = Process.GetProcessById(processId);
            IntPtr handle = process.MainWindowHandle;

            if (handle == IntPtr.Zero)
                return;

            SetForegroundWindow(handle);
        }

        public static void CenterProcessWindow(int processId)
        {
            Process process = Process.GetProcessById(processId);
            IntPtr handle = process.MainWindowHandle;

            if (handle != IntPtr.Zero)
            {
                RECT rct;
                GetWindowRect(handle, out rct);
                Rectangle screen = Screen.FromHandle(handle).Bounds;
                Point pt = new Point(screen.Left + screen.Width / 2 - (rct.Right - rct.Left) / 2, screen.Top + screen.Height / 2 - (rct.Bottom - rct.Top) / 2);
                SetWindowPos(handle, IntPtr.Zero, pt.X, pt.Y, 0, 0, SWP_NOZORDER | SWP_NOSIZE | SWP_SHOWWINDOW);
            }


        }
    }
}

The problem is if the process already running and i drag the process window to the one of the screen corners click on empty are in the screen so now the process is in the background and then running my program it will bring the process handle window to the front and center it.

But if i drag the process window to somewhere in the screen not the center and quit the process then running my program and it's running the process it will bring it to front but will not center it.

Why when the process is not running and my program running the process it dosent center it ?

Answer 1

Your process window is shown immediately, but it's not fully set up so you won't probably even get results debugging because if you go through debugger enough time will pass and handle will be created so everything will work fine for you. What you need to do is wait for your MainWindowHandle to be set. You can modify your CenterProcessWindow method like this:

public static void CenterProcessWindow(int processId)
{
    Process process = Process.GetProcessById(processId);

    while (process.MainWindowHandle == IntPtr.Zero)
        process.Refresh();

    IntPtr handle = process.MainWindowHandle;

    RECT rct;
    GetWindowRect(handle, out rct);
    Rectangle screen = Screen.FromHandle(handle).Bounds;
    Point pt = new Point(screen.Left + screen.Width / 2 - (rct.Right - rct.Left) / 2, screen.Top + screen.Height / 2 - (rct.Bottom - rct.Top) / 2);
    SetWindowPos(handle, IntPtr.Zero, pt.X, pt.Y, 0, 0, SWP_NOZORDER | SWP_NOSIZE | SWP_SHOWWINDOW);
}