在Windows Mobile和Wince(Windows Embedded CE)下进行Win32开发，取出当前所有运行中进程信息的方法

寇平同学问我使用Native C++开发时如何在取出进程下窗口的句柄，因为取进程下窗口句柄需要用到进程信息，我先总结出如何取出当前所有运行进程信息的方法。

1.引用Tlhelp32.h文件

#include "Tlhelp32.h"

因为需要用到CreateToolhelp32Snapshot，Process32First和Process32Next来查询进程信息。

2.轮询进程信息

void GetRunningProcesses()
{
    processes.clear();
    HANDLE hSnapShot = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
    
    //Do a little error handling, just in case.
    if(hSnapShot == (HANDLE)-1)
    {
        wprintf(TEXT("GetRunningProcesses: Failed CreateToolhelp32Snapshot Error: %d\n"),
            GetLastError());
        return;
    }

    PROCESSENTRY32 process;
    process.dwSize = sizeof(PROCESSENTRY32);
    BOOL retval = Process32First(hSnapShot, &process);
    while(retval)
    {
        processes.push_back(process);
        retval = Process32Next(hSnapShot, &process);
    }
    
    //Always good to close those handles.  Then return the number of processes that we found.
    CloseToolhelp32Snapshot (hSnapShot);
}

这是本文的重点，我把查询到的进行信息放到一个全局的list里面去了，可能封装为对象。

#include <list>

std::list<PROCESSENTRY32> processes;

3.显示进程信息

void ShowRunningProcesses()
{
    GetRunningProcesses();
    DWORD maxProcessNameLength = GetMaxProcessNameLength();
    // Output a header to describe each column
    wprintf(TEXT("%-*s %8s %13s %9s %9s %10s\n"),
        maxProcessNameLength,
        TEXT("Process"),
        TEXT("PID"),
        TEXT("Base Priority"),
        TEXT("# Threads"),
        TEXT("Base Addr"),
        TEXT("Access Key")
        );

    // Output information for each running process
    for( std::list<PROCESSENTRY32>::iterator it=processes.begin();
        it!=processes.end(); ++it)
    {
        wprintf(TEXT("%-*s %8X %13d %9d %9X %10X\n"), 
            maxProcessNameLength,
            it->szExeFile,
            it->th32ProcessID,
            it->pcPriClassBase,
            it->cntThreads,
            it->th32MemoryBase,
            it->th32AccessKey
            );
    }
}

DWORD GetMaxProcessNameLength()
{
    DWORD maxLength = 0;
    DWORD currentLength;
    for( std::list<PROCESSENTRY32>::iterator it=processes.begin();
        it!=processes.end(); ++it)
    {
        currentLength = wcslen( it->szExeFile );
        if( maxLength <  currentLength )
        {
            maxLength = currentLength;
        }
    }
    return maxLength;
}