winform实现单进程

原文地址：https://bbs.et8.net/bbs/archive/index.php/t-399247.html

 

ex:
if (SingleInstance.SingleApplication.Run( " Fish " ))
System.Windows.Forms.Application.Run( new  fish.Forms());
}

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

namespace  SingleInstance
{
///   <summary>
///  Summary description for SingleApp.
///   </summary>
public   class  SingleApplication
{
private  SingleApplication()
{

}
///   <summary>
///  Imports 
///   </summary>

[DllImport( " user32.Dll " )]
private   static   extern   int  EnumWindows(EnumWinCallBack callBackFunc,  int  lParam); 

[DllImport( " User32.Dll " )]
private   static   extern   void  GetWindowText( int  hWnd, StringBuilder str,  int  nMaxCount);

[DllImport( " user32.dll " ,EntryPoint = " SetForegroundWindow " )]
private   static   extern   bool  SetForegroundWindow(IntPtr hWnd);

[DllImport( " user32.dll " )]
private   static   extern  Boolean ShowWindow(IntPtr hWnd,Int32 nCmdShow);

///   <summary>
///  EnumWindowCallBack
///   </summary>
///   <param name="hwnd"></param>
///   <param name="lParam"></param>
///   <returns></returns>
private   static   bool  EnumWindowCallBack( int  hwnd,  int  lParam) 
{ 
windowHandle  =  (IntPtr)hwnd;

StringBuilder sbuilder  =   new  StringBuilder( 256 );
GetWindowText(( int )windowHandle, sbuilder, sbuilder.Capacity);
string  strTitle  =  sbuilder.ToString();

if (strTitle  ==  sTitle)
{
ShowWindow(windowHandle, SW_RESTORE); 
SetForegroundWindow(windowHandle);
return   false ;
}
return   true ;
} // EnumWindowCallBack

///   <summary>
///  Execute a form base application if another instance already running on
///  the system activate previous one
///   </summary>
///   <param name="frmMain"> main form </param>
///   <returns> true if no previous instance is running </returns>
public   static   bool  Run(System.Windows.Forms.Form frmMain)
{
sTitle  =  frmMain.Text;

if ( EnumWindows ( new  EnumWinCallBack(EnumWindowCallBack),  0 )  ==   0 )
{
return   false ;
}
Application.Run(frmMain);
return   true ;
}

public   static   bool  Run( string  frmText)
{
sTitle  =  frmText;

if ( EnumWindows ( new  EnumWinCallBack(EnumWindowCallBack),  0 )  ==   0 )
{
return   false ;
}
return   true ;
}

///   <summary>
///  
///   </summary>
///   <returns></returns>
public   static   bool  Run()
{
Process pr  =  Process.GetCurrentProcess();
string  strProcessName  =  pr.ProcessName;
if (System.Diagnostics.Process.GetProcessesByName(strProcessName).Length  >   1 ) 
{
return   false ;
}
return   true ;
}

const   int  SW_RESTORE  =   9 ;
static   string  sTitle;
static  IntPtr windowHandle;
delegate   bool  EnumWinCallBack( int  hwnd,  int  lParam);
}
}