对于存在窗体的WPF程序（或者说，起码在任务栏上有个图标，即ShowInTaskbar = true），互相传递消息是很容易的。
步骤：
1，寻找窗体的句柄
2，运用windows API: SendMessage或PostMessage
3，目标窗体收到消息
这里的代码，展示了一个APP不希望多开所以在启动时检查是否存在一个已经运行的进程。如果进程已经存在，则给对方发送消息并结束自身。
1.判断/获取已经运行的实例
/// <summary>
/// 获取当前exe文件的是否已经在电脑上运行了一个实例，如果是，则返回那个实例的Process；如果否，就返回null；
/// 如果有窗体，可以通过process.MainWindowHandle获取窗体的句柄，如果没窗体（ShowInTaskbar = false）,则句柄为空
/// </summary>
public static Process GetCurrentExeProcess()
{
Process targetProcess = null;
Process currentProcess = Process.GetCurrentProcess();
string exeName = string.Format("{0}.exe", currentProcess.ProcessName);
//PTZ.Tracer.AppLog.Info("$$$$$Get Current Process Successfully, current process exe: {0}", exeName);
try
{
Process[] aryProcess = Process.GetProcessesByName(currentProcess.ProcessName);
//PTZ.Tracer.AppLog.Info("$$$$$Get aryProcess Successfully, aryProcess count: {0}", aryProcess.Count());
foreach (Process process in aryProcess)
{
if (process.Id != currentProcess.Id && process.ProcessName == currentProcess.ProcessName)
{
targetProcess = process;
//PTZ.Tracer.AppLog.Info("$$$$$Get MainWindowHandle Successfully, hWnd: {0}", hWnd);
break;
}
}
}
catch (System.PlatformNotSupportedException pEx)
{
//PTZ.Tracer.AppLog.Error("$$$$$GetCurrentWindowsInstanceHandle exception:", pEx);
}
catch (System.InvalidOperationException iEx)
{
//PTZ.Tracer.AppLog.Error("$$$$$GetCurrentWindowsInstanceHandle exception:", iEx);
}
catch (System.ComponentModel.Win32Exception win32Ex)
{
//PTZ.Tracer.AppLog.Error("$$$$$GetCurrentWindowsInstanceHandle exception:", win32Ex);
}
return targetProcess;
}
但是这个方法在某些奇怪权限设置的电脑上会遭遇UnauthorizedException，所以，如果只是想获取窗体句柄的话，还可以将上述方法的Try & Catch部分换成下面的代码：
try
{
string wmiQueryString = string.Format("SELECT ProcessId, Handle,ExecutablePath,Name FROM Win32_Process WHERE ProcessId != {0} AND Name = '{1}'", currentProcess.Id, exeName);
using (var searcher = new ManagementObjectSearcher(wmiQueryString))
{
using (var results = searcher.Get())
{
ManagementObject mo = results.Cast<ManagementObject>().FirstOrDefault();
if (mo != null)
{
string s = (string)mo["ExecutablePath"];
string handleStr = (string)mo["Handle"];
string sss = (string)mo["Name"];
Tracing.Trace.Information("￥*￥ManagementObjectSearcher, name: {0} Handle: {1} Path: {2}", sss, handleStr, s);
int handle = int.Parse(handleStr);
Process p = Process.GetProcessById(handle);
hWnd = p.MainWindowHandle;
isRunExist = true;
Tracing.Trace.Information("￥*￥ManagementObjectSearcher, hWnd: {0}", hWnd);
}
}
}
}
catch (Exception e)
{
Tracing.Trace.Error("ManagementObjectSearcher exception:", e);
}
2.注册WindowsAPI
#region Dll Imports
[DllImport("user32.dll")]
static extern IntPtr PostMessage(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam);
public const uint WM_APP = 0x9112;////0x8001~0xBFFF，随意#endregion Dll Imports
3.修改App.OnStartup方法
当程序启动，就需要检测实例。如已有实例运行，则发送消息；如没有，则继续正常运行。所以我们需要修改Appxaml.cs的OnStartup方法：
protected override void OnStartup(StartupEventArgs e)
{
base.OnStartup(e);
Process targetProcess = SingleExeHelper.GetCurrentExeProcess();
if (targetProcess!=null)//Software has been running...
{
//currentHandle通过targetProcess.MainWindowHandle得到
PostMessage(currentHandle,WM_APP, IntPtr.Zero, IntPtr.Zero);
Environment.Exit(0);//Software has been running, close this
}
else
{
//do nothing
}
}
4.主窗体监听消息：
protected override void OnSourceInitialized(EventArgs e)
{
base.OnSourceInitialized(e);
((HwndSource)PresentationSource.FromVisual(this)).AddHook(myHook);
//HwndSource source = HwndSource.FromHwnd(new WindowInteropHelper(this).Handle);
//source.AddHook(new HwndSourceHook(myHook));
}
private IntPtr myHook(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
{
int m = (int)App.WM_APP;
if (msg == m)
{
System.Windows.MessageBox.Show("haha");
}
return IntPtr.Zero;
}
对于存在窗体的WPF程序（或者说，起码在任务栏上有个图标，即ShowInTaskbar = true），互相传递消息是很容易的。
步骤：
1，寻找窗体的句柄
2，运用windows API: SendMessage或PostMessage
3，目标窗体收到消息
这里的代码，展示了一个APP不希望多开所以在启动时检查是否存在一个已经运行的进程。如果进程已经存在，则给对方发送消息并结束自身。
1.判断/获取已经运行的实例
/// <summary>
/// 获取当前exe文件的是否已经在电脑上运行了一个实例，如果是，则返回那个实例的Process；如果否，就返回null；
/// 如果有窗体，可以通过process.MainWindowHandle获取窗体的句柄，如果没窗体（ShowInTaskbar = false）,则句柄为空
/// </summary>
public static Process GetCurrentExeProcess()
{
Process targetProcess = null;
Process currentProcess = Process.GetCurrentProcess();
string exeName = string.Format("{0}.exe", currentProcess.ProcessName);
//PTZ.Tracer.AppLog.Info("$$$$$Get Current Process Successfully, current process exe: {0}", exeName);
try
{
Process[] aryProcess = Process.GetProcessesByName(currentProcess.ProcessName);
//PTZ.Tracer.AppLog.Info("$$$$$Get aryProcess Successfully, aryProcess count: {0}", aryProcess.Count());
foreach (Process process in aryProcess)
{
if (process.Id != currentProcess.Id && process.ProcessName == currentProcess.ProcessName)
{
targetProcess = process;
//PTZ.Tracer.AppLog.Info("$$$$$Get MainWindowHandle Successfully, hWnd: {0}", hWnd);
break;
}
}
}
catch (System.PlatformNotSupportedException pEx)
{
//PTZ.Tracer.AppLog.Error("$$$$$GetCurrentWindowsInstanceHandle exception:", pEx);
}
catch (System.InvalidOperationException iEx)
{
//PTZ.Tracer.AppLog.Error("$$$$$GetCurrentWindowsInstanceHandle exception:", iEx);
}
catch (System.ComponentModel.Win32Exception win32Ex)
{
//PTZ.Tracer.AppLog.Error("$$$$$GetCurrentWindowsInstanceHandle exception:", win32Ex);
}
return targetProcess;
}
但是这个方法在某些奇怪权限设置的电脑上会遭遇UnauthorizedException，所以，如果只是想获取窗体句柄的话，还可以将上述方法的Try & Catch部分换成下面的代码：
try
{
string wmiQueryString = string.Format("SELECT ProcessId, Handle,ExecutablePath,Name FROM Win32_Process WHERE ProcessId != {0} AND Name = '{1}'", currentProcess.Id, exeName);
using (var searcher = new ManagementObjectSearcher(wmiQueryString))
{
using (var results = searcher.Get())
{
ManagementObject mo = results.Cast<ManagementObject>().FirstOrDefault();
if (mo != null)
{
string s = (string)mo["ExecutablePath"];
string handleStr = (string)mo["Handle"];
string sss = (string)mo["Name"];
Tracing.Trace.Information("￥*￥ManagementObjectSearcher, name: {0} Handle: {1} Path: {2}", sss, handleStr, s);
int handle = int.Parse(handleStr);
Process p = Process.GetProcessById(handle);
hWnd = p.MainWindowHandle;
isRunExist = true;
Tracing.Trace.Information("￥*￥ManagementObjectSearcher, hWnd: {0}", hWnd);
}
}
}
}
catch (Exception e)
{
Tracing.Trace.Error("ManagementObjectSearcher exception:", e);
}
2.注册WindowsAPI
#region Dll Imports
[DllImport("user32.dll")]
static extern IntPtr PostMessage(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam);
public const uint WM_APP = 0x9112;////0x8001~0xBFFF，随意#endregion Dll Imports
3.修改App.OnStartup方法
当程序启动，就需要检测实例。如已有实例运行，则发送消息；如没有，则继续正常运行。所以我们需要修改Appxaml.cs的OnStartup方法：
protected override void OnStartup(StartupEventArgs e)
{
base.OnStartup(e);
Process targetProcess = SingleExeHelper.GetCurrentExeProcess();
if (targetProcess!=null)//Software has been running...
{
//currentHandle通过targetProcess.MainWindowHandle得到
PostMessage(currentHandle,WM_APP, IntPtr.Zero, IntPtr.Zero);
Environment.Exit(0);//Software has been running, close this
}
else
{
//do nothing
}
}
4.主窗体监听消息：
protected override void OnSourceInitialized(EventArgs e)
{
base.OnSourceInitialized(e);
((HwndSource)PresentationSource.FromVisual(this)).AddHook(myHook);
//HwndSource source = HwndSource.FromHwnd(new WindowInteropHelper(this).Handle);
//source.AddHook(new HwndSourceHook(myHook));
}
private IntPtr myHook(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
{
int m = (int)App.WM_APP;
if (msg == m)
{
System.Windows.MessageBox.Show("haha");
}
return IntPtr.Zero;
}
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