转载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);
}
}