CreateToolhelp32Snapshot 按名称查ID？解决办法

CreateToolhelp32Snapshot 按名称查ID？？
我按网上的资料写了一个按名称查进程ID,但是总是返回的是内存中没有进程，即（Process32First(handle, ref info)一直返回是0）我确定我PDA（MC35--WM6）中是有进程的

C# code

 
[DllImport("toolhelp.dll")]
private static extern int Process32First(IntPtr hSnapshot, ref PROCESSENTRY32 lppe);

[DllImport("toolhelp.dll")]
private static extern int Process32Next(IntPtr hSnapshot,ref PROCESSENTRY32 lppe);

[DllImport("toolhelp.dll", SetLastError = true)]
private static extern IntPtr CreateToolhelp32Snapshot(uint dwFlags,uint th32ProcessID);

private const uint TH32CS_SNAPPROCESS = 0x00000002;

[StructLayout(LayoutKind.Sequential)]
private struct PROCESSENTRY32
{
   public uint dwSize;
   public uint cntUsage;
   public uint th32ProcessID;
   public IntPtr th32DefaultHeapID;
   public uint th32ModuleID;
   public uint cntThreads;
   public uint th32ParentProcessID;
   public int pcPriClassBase;
   public uint dwFlags;
   [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 260)]
   public string szExeFile;
}

private void button1_Click(object sender, EventArgs e)
{
   IntPtr handle = IntPtr.Zero;
   try
   {
       handle = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
       PROCESSENTRY32 info = new PROCESSENTRY32();
       info.dwSize = (uint)Marshal.SizeOf(typeof(PROCESSENTRY32));
       int first = Process32First(handle, ref info);
       if (first == 0)
           MessageBox.Show("no pr");
       else
       {
          do
          {
             if (string.Compare(info.szExeFile,"CamWedge.exe", true) == 0)
                MessageBox.Show("yes");
           }
           while (Process32Next(handle, ref info) != 0);
        }
    }
    catch
    {  throw;  }
}

------解决方案--------------------
debug看看CreateToolhelp32Snapshot()返回的handle是不是有效的。

如果handle有效的话，再dllimport GetLastError()看看错误代码是什么，然后到WM SDK下的winerror.h文件中查找一下是什么问题。
------解决方案--------------------
C# 没搞过，不过c++调用肯定是没有问题的
------解决方案--------------------
dllimport改下试试：

[DllImport( "toolhelp.dll ")]
public static extern IntPtr CreateToolhelp32Snapshot(uint dwFlags, uint th32ProcessID);
[DllImport( "toolhelp.dll ")]
public static extern int Process32First(int snaph, ref PROCESSENTRY32 lppe);
[DllImport( "toolhelp.dll ")]
public static extern int Process32Next(IntPtr snaph, ref PROCESSENTRY32 lppe);

CreateToolhelp32Snapshot 按名称查ID？解决办法

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