这是我目前所拥有的：
Dim bProcess = Process.GetProcessesByName("By").FirstOrDefault
If bProcess IsNot Nothing Then
SwitchToThisWindow(bProcess.MainWindowHandle, True)
Else
Process.Start("C:\Program Files\B\B.exe")
End If
它有两个问题。
那么正确的做法是什么？
【问题讨论】：
获取窗口句柄（hwnd），然后使用这个user32.dll函数：
VB.net 声明：
Declare Function SetForegroundWindow Lib "user32.dll" (ByVal hwnd As Integer) As Integer
C# 声明：
[DllImport("user32.dll")] public static extern int SetForegroundWindow(int hwnd)
一个考虑是，如果窗口被最小化，这将不起作用，所以我编写了以下方法来处理这种情况。这是 C# 代码，将其迁移到 VB 应该相当简单。
[System.Runtime.InteropServices.DllImport("user32.dll")]
[return: System.Runtime.InteropServices.MarshalAs(System.Runtime.InteropServices.UnmanagedType.Bool)]
private static extern bool ShowWindow(IntPtr hWnd, ShowWindowEnum flags);
[System.Runtime.InteropServices.DllImport("user32.dll")]
private static extern int SetForegroundWindow(IntPtr hwnd);
private enum ShowWindowEnum
{
Hide = 0,
ShowNormal = 1, ShowMinimized = 2, ShowMaximized = 3,
Maximize = 3, ShowNormalNoActivate = 4, Show = 5,
Minimize = 6, ShowMinNoActivate = 7, ShowNoActivate = 8,
Restore = 9, ShowDefault = 10, ForceMinimized = 11
};
public void BringMainWindowToFront(string processName)
{
// get the process
Process bProcess = Process.GetProcessesByName(processName).FirstOrDefault();
// check if the process is running
if (bProcess != null)
{
// check if the window is hidden / minimized
if (bProcess.MainWindowHandle == IntPtr.Zero)
{
// the window is hidden so try to restore it before setting focus.
ShowWindow(bProcess.Handle, ShowWindowEnum.Restore);
}
// set user the focus to the window
SetForegroundWindow(bProcess.MainWindowHandle);
}
else
{
// the process is not running, so start it
Process.Start(processName);
}
}
使用该代码，只需设置适当的流程变量并调用BringMainWindowToFront("processName");
【讨论】：
还有另一种方式，它使用了不知名的 UI 自动化 API：
AutomationElement element = AutomationElement.FromHandle(process.MainWindowHandle);
if (element != null)
{
element.SetFocus();
}
大多数情况下，如果可以切换到该窗口，这将起作用。 Windows 中有很多限制（安全性、UAC、特定配置等），可能会阻止您更改最终用户的关注点。
【讨论】：
在您的项目中创建一个新类并将以下代码复制粘贴到其中。
using System;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Threading;
namespace MyProject
{
public class ProcessHelper
{
public static void SetFocusToExternalApp(string strProcessName)
{
Process[] arrProcesses = Process.GetProcessesByName(strProcessName);
if (arrProcesses.Length > 0)
{
IntPtr ipHwnd = arrProcesses[0].MainWindowHandle;
Thread.Sleep(100);
SetForegroundWindow(ipHwnd);
}
}
//API-declaration
[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
public static extern bool SetForegroundWindow(IntPtr hWnd);
}
}
现在将以下代码复制粘贴到您需要的区域。
string procName = Process.GetCurrentProcess().ProcessName;
ProcessHelper.SetFocusToExternalApp(procName);
在这里，您正在调用该函数以将焦点转移到其他应用程序的窗口。
【讨论】：
在 VB.Net 中，您可以使用AppActivate 函数。
Dim App As Process() = Process.GetProcessesByName("program.exe")
If App.Length > 0 Then
AppActivate(App(0).Id)
End If
【讨论】：
我使用 SetForegroundWindow 使来自另一个应用程序的窗口出现。
[DllImport("user32.dll")]
static extern bool SetForegroundWindow(IntPtr hWnd);
【讨论】：
进口：
Imports System.Runtime.InteropServices
把它放在一个模块中
<DllImport("user32.dll")> _
Private Function SetForegroundWindow(hWnd As IntPtr) As Boolean
End Function
Public Sub FocusWindow(ByVal ProcessName As String)
Dim p As System.Diagnostics.Process = System.Diagnostics.Process.GetProcessesByName(ProcessName).FirstOrDefault
If p IsNot Nothing Then
SetForegroundWindow(p.MainWindowHandle)
SendKeys.SendWait("~") ' maximize the application if it's minimized
End If
End Sub
用法：
FocusWindow("Notepad")
来源：http://www.codeproject.com/Tips/232649/Setting-Focus-on-an-External-application#_rating
【讨论】：
这对我有用
[DllImport("user32.dll", SetLastError = true)]
static extern void SwitchToThisWindow(IntPtr hWnd, bool turnOn);
[STAThread]
static void Main()
{
Process bProcess = Process.GetProcessesByName(processnamehere).FirstOrDefault() ;
if (bProcess != null)
{
SwitchToThisWindow(bProcess.MainWindowHandle, true);
}
GC.Collect();
}
【讨论】：
以下对我有用，当我尝试使用从以下代码获得的exe 以 Administrator 身份运行 SQL Server Management Studio 和 Visual Studio 等应用程序时。
切换助手
public class ToggleHelper
{
[System.Runtime.InteropServices.DllImport("user32.dll")]
[return: System.Runtime.InteropServices.MarshalAs(System.Runtime.InteropServices.UnmanagedType.Bool)]
private static extern bool ShowWindow(IntPtr hWnd, EnumForWindow enumVal);
[System.Runtime.InteropServices.DllImport("user32.dll")]
private static extern int SetForegroundWindow(IntPtr hwnd);
private enum EnumForWindow
{
Hide = 0,
ShowNormal = 1, ShowMinimized = 2, ShowMaximized = 3,
Maximize = 3, ShowNormalNoActivate = 4, Show = 5,
Minimize = 6, ShowMinNoActivate = 7, ShowNoActivate = 8,
Restore = 9, ShowDefault = 10, ForceMinimized = 11
};
public void SetForeGroundMainWindowHandle(string processName)
{
Console.WriteLine("SetForeGroundMainWindowHandle Called - for "+ processName);
Process p = Process.GetProcessesByName(processName).FirstOrDefault();
if (p != null)
{
Console.WriteLine(p.MainWindowHandle.ToString());
ShowWindow(p.MainWindowHandle, EnumForWindow.Restore);
System.Threading.Thread.Sleep(5000);
ShowWindow(p.MainWindowHandle, EnumForWindow.ShowMaximized);
//System.Threading.Thread.Sleep(5000);
SetForegroundWindow(p.MainWindowHandle);
}
else
{
Process.Start(processName);
}
}
}
客户
class Program
{
static void Main(string[] args)
{
//RUN AS Administrator
var y = Process.GetProcesses().Where(pr => pr.MainWindowHandle != IntPtr.Zero);
foreach (Process proc in y)
{
Console.WriteLine(proc.ProcessName);
}
ToggleHelper t = new ToggleHelper();
int a = 0;
while (a <= 1)
{
t.SetForeGroundMainWindowHandle("Ssms");
System.Threading.Thread.Sleep(30000);
t.SetForeGroundMainWindowHandle("devenv");
System.Threading.Thread.Sleep(18000);
}
Console.ReadLine();
}
}
【讨论】：