c# 调用windows api

Question

   /*
      BOOL WINAPI CryptEnumProviders(
  DWORD dwIndex,
  DWORD* pdwReserved,
  DWORD dwFlags,
  DWORD* pdwProvType,
  LPTSTR pszProvName,//
  DWORD* pcbProvName //
);*/
       [DllImport("advapi32.dll", SetLastError = true, CharSet = CharSet.Auto)]
      public static extern bool CryptEnumProviders(uint dwIndex,  ref uint pdwReserved,
           uint dwFlags,ref uint pdwProvType,ref string pszProvName,ref uint pcbProvName);
这个函数这么声明对吗? 该如何调用.请大家给个例子.

Answer 1

[DllImport("advapi32.dll", SetLastError=true, CharSet=CharSet.Auto)]
static extern bool CryptEnumProviders(
    [MarshalAs(UnmanagedType.U4)] int dwIndex,
    [MarshalAs(UnmanagedType.U4)] ref int pdwReserved,
    [MarshalAs(UnmanagedType.U4)] int dwFlags,
    [MarshalAs(UnmanagedType.U4)] ref int pdwProvType,
    StringBuilder pszProvName,
    [MarshalAs(UnmanagedType.U4)] ref int pcbProvName);
  
*****************************************************************************
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Answer 2

3楼的,请给我写个调的例子.我见过这么声明的.但是我调的不对.
uint pdwReserved,pdwProvType,pdwProvType
CryptEnumProviders(0, pdwReserved, 0, ref pdwProvType, ref pszProvName, ref pdwProvType);
请给我写个怎么调的吧.我调的老是出错!

Answer 3

这样试试：
public static extern bool CryptEnumProviders(UInt32 dwIndex, IntPtr pdwReserved, UInt32 dwFlags, ref UInt32 pdwProvType, StringBuilder pszProvName, ref UInt32 pcbProvName);UInt32 pdwProvType;
UInt32 pcbProvName = 100;
StringBuilder pszProvName = new StringBuilder(pcbProvName);
CryptEnumProviders(0, IntPtr.Zero, 0, ref pdwProvType, pszProvName, ref pcbProvName);

Answer 4

http://download.csdn.net/source/1223372
参考 里面有调用声音API和获取计算机系统信息的 API