Re: [問題] process.start 外部程式 視窗焦點

[TeemingVoid (TeemingVoid)]

※ 引述《yeahhey (神秘人)》之銘言：
: 大家好
: 小弟最近在用process.StartInfo來啟動外部程式
: 功能上想要達到
: buttom_click後，可以依序把多個外部程式啟動完(利用來處理資料的外部程式)
: (例如:先A，A結束後再B，B結束在C...)
: 這些執行序的視窗，目前程式都設定縮到最小
: 現在問題是
: ...

一開始其實看不懂你在寫什麼 :p (抱歉)，後來才發現原來是指 A 程式結束後，
接下來要啟動 B 程式時，最前景視窗會失去視窗焦點(focus)。

請這樣試試看合不合你的需要:

1. 新建一個 Windows Form 專案，名稱(例如)叫: StartOneByOne

2. 在 Form1 擺一個 Button，Button1 滑鼠點兩下，準備寫 Click 事件。

3. using 以下 namespace:
using System.Diagnostics;
using System.Runtime.InteropServices;

4. 在 Click 事件前，貼入下列 Windows API 宣告:

[DllImport("user32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool ShowWindow(IntPtr hWnd, ShowWindowCommands nCmdShow);

enum ShowWindowCommands : int
{
    /// <summary>
    /// Hides the window and activates another window.
    /// </summary>
    Hide = 0,
    /// <summary>
    /// Activates and displays a window. If the window is minimized or
    /// maximized, the system restores it to its original size and position.
    /// An application should specify this flag when displaying the window
    /// for the first time.
    /// </summary>
    Normal = 1,
    /// <summary>
    /// Activates the window and displays it as a minimized window.
    /// </summary>
    ShowMinimized = 2,
    /// <summary>
    /// Maximizes the specified window.
    /// </summary>
    Maximize = 3, // is this the right value?
    /// <summary>
    /// Activates the window and displays it as a maximized window.
    /// </summary>
    ShowMaximized = 3,
    /// <summary>
    /// Displays a window in its most recent size and position. This value
    /// is similar to <see cref="Win32.ShowWindowCommand.Normal"/>, except
    /// the window is not activated.
    /// </summary>
    ShowNoActivate = 4,
    /// <summary>
    /// Activates the window and displays it in its current size and
    /// position.
    /// </summary>
    Show = 5,
    /// <summary>
    /// Minimizes the specified window and activates the next top-level
    /// window in the Z order.
    /// </summary>
    Minimize = 6,
    /// <summary>
    /// Displays the window as a minimized window. This value is similar to
    /// <see cref="Win32.ShowWindowCommand.ShowMinimized"/>, except the
    /// window is not activated.
    /// </summary>
    ShowMinNoActive = 7,
    /// <summary>
    /// Displays the window in its current size and position. This value is
    /// similar to <see cref="Win32.ShowWindowCommand.Show"/>, except the
    /// window is not activated.
    /// </summary>
    ShowNA = 8,
    /// <summary>
    /// Activates and displays the window. If the window is minimized or
    /// maximized, the system restores it to its original size and position.
    /// An application should specify this flag when restoring a minimized
    /// window.
    /// </summary>
    Restore = 9,
    /// <summary>
    /// Sets the show state based on the SW_* value specified in the
    /// STARTUPINFO structure passed to the CreateProcess function by the
    /// program that started the application.
    /// </summary>
    ShowDefault = 10,
    /// <summary>
    ///  <b>Windows 2000/XP:</b> Minimizes a window, even if the thread
    /// that owns the window is not responding. This flag should only be
    /// used when minimizing windows from a different thread.
    /// </summary>
    ForceMinimize = 11
}


5. 按鈕的 Click 事件處理函式則類似這樣:

private void button1_Click(object sender, EventArgs e)
{
    // testLab.exe 是我另外寫的測試程式，它五秒後會自動結束
    string[] Programs = new string[] { @"c:\temp\testLab.exe",
                                       @"notepad.exe" };
    foreach (string sProgram in Programs)
    {
        ProcessStartInfo psi = new ProcessStartInfo(sProgram);
        // 一開始是極小化
        psi.WindowStyle = ProcessWindowStyle.Minimized;
        Process p = Process.Start(psi);
        // 等待程式確實 run 起來...
        while (p.MainWindowHandle == IntPtr.Zero)
        {
            System.Threading.Thread.Sleep(100);
            p.Refresh();
        }

        // 測試後，發現主視窗也要極小化。
        ShowWindow(this.Handle, ShowWindowCommands.Minimize);
        // 隱藏工作視窗，這樣 focus 自然釋出
        ShowWindow(p.MainWindowHandle, ShowWindowCommands.Hide);
        // 重新將工作視窗設為極小化
        ShowWindow(p.MainWindowHandle, ShowWindowCommands.Minimize);

        // p.WaitForExit();
        while (!p.HasExited)
        {
            System.Threading.Thread.Sleep(100);
            Application.DoEvents();
        }
    }
}


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◆ From: 118.170.128.145
推 yeahhey:先感謝你!!我有個問題是  他這樣會有焦點變化嗎?
→ yeahhey:start後的瞬間  焦點還是會被啟動的程式奪去  在還回?
→ yeahhey:我原本想找看看有沒有函示可以直接設定不要搶走焦點= =
→ yeahhey:但最後也是找到你這邊提到的ShowWindowCommands!
→ TeemingVoid:一旦呼叫 Process.Start()，focus 就會被新視窗搶走，
推 yeahhey:會問有沒有焦點變化  主要是擔心某個使用中全螢幕的視窗
→ TeemingVoid:ShowWindow(..., Hide); 的作用在於隱藏新的視窗，
→ yeahhey:會因為focus改變而縮小或是瞬間縮小又切回來
→ TeemingVoid:這樣 focus 自然釋出。
→ yeahhey:因為Process.Start()會搶focus，我現在改用CreateProcess
→ yeahhey:外部程式的作法除了process，另外查到shellExecute
→ yeahhey:跟CreateProcess~~  shellExecute跟CreateProcess可以直接
→ TeemingVoid:我猜你這樣的結果可能一樣，視窗焦點還是會被搶走 :)
→ yeahhey:設定ShowWindowCommands(與啟動同一行指令下設定)
→ yeahhey:你這樣一講我也覺得  那兩種內部運作應該也跟你的一樣= =
→ yeahhey:我開個youtube測測看會不會跳掉好了= =
→ TeemingVoid:以前我曾用過 Sendkeys.Send("+{Tab}"); // Alt + Tab
→ TeemingVoid:但是效果並不好...
推 yeahhey:youtube全螢幕看起來沒影響..kmp全螢幕會突然跳出
→ TeemingVoid:隱藏視窗自然釋出焦點，比較自然，你再試試囉!晚安!^^
→ yeahhey:跳出最下排的程式縮圖= =..所以內部運作應該跟寫法你一樣!
→ yeahhey:嗯嗯感謝你~~