Question

   DWORD OREnumKey(
      __in         ORHKEY Handle,
      __in         DWORD dwIndex,
      __out        PWSTR lpName,
      __inout      PDWORD lpcName,
      __out_opt    PWSTR lpClass,
      __inout_opt  PDWORD lpcClass,
      __out_opt    PFILETIME lpftLastWriteTime
    );

我的代码

[DllImport("offreg.dll", CharSet = CharSet.Unicode, SetLastError = true)]
public static extern uint OREnumKey(IntPtr Handle, IntPtr dwIndex, [MarshalAs(UnmanagedType.LPWStr)]out StringBuilder lpName, ref IntPtr lpcName, [MarshalAs(UnmanagedType.LPWStr)]out StringBuilder lpClass, ref IntPtr lpcClass, out System.Runtime.InteropServices.ComTypes.FILETIME lpftLastWriteTime);
 IntPtr myKey = hiveid;
    IntPtr dwindex=(IntPtr)0;
    StringBuilder lpName=new StringBuilder("",255);
    IntPtr lpcName = (IntPtr)0;
    StringBuilder  lpClass=new StringBuilder("",255);
    IntPtr lpcClass = (IntPtr)11;
    System.Runtime.InteropServices.ComTypes.FILETIME lpftLastWriteTime;
    uint ret3 = OREnumKey(myKey, dwindex, out lpName, ref lpcName, out lpClass, ref lpcClass, out lpftLastWriteTime);

ret3 = ERROR_MORE_DATA 234 问题可能在错误的StringBuilder大小或FILETIME中第二部我应如何从C＃调用PWSTR参数？ [MarshalAs(UnmanagedType.LPWStr)]out StringBuilder lpName这是正确的吗？

Answer 1

这是一个相当标准的Windows错误代码，这意味着您调用了一个winapi函数并且没有传递足够大的缓冲区。解决问题的唯一方法是传递更大的缓冲区。

这看起来很像RegQueryKeyEx（）的包装器，这使得很可能将错误的数据传递给函数。 lpcName 参数实际上是ref int，而不是IntPtr。并且您应该传递一个变量来存储您传递的缓冲区的大小，在您的情况下为255。 lpcClass参数同样是borked。这应该解决它：

[DllImport("offreg.dll", CharSet = CharSet.Unicode, SetLastError = true)]
public static extern uint OREnumKey(
    IntPtr Handle, 
    int dwIndex,
    StringBuilder lpName, 
    ref int lpcName, 
    StringBuilder lpClass, 
    ref int lpcClass, 
    out System.Runtime.InteropServices.ComTypes.FILETIME lpftLastWriteTime);

    ...   
    StringBuilder lpName=new StringBuilder("",255);
    int nameSize = lpName.Capacity;
    StringBuilder  lpClass=new StringBuilder("",255);
    int classSize = lpClass.Capacity;
    System.Runtime.InteropServices.ComTypes.FILETIME lpftLastWriteTime;
    uint ret3 = OREnumKey(hiveid, 0, lpName, ref nameSize, lpClass, ref classSize, out lpftLastWriteTime);
    if (ret3 != 0) throw new Exception("kaboom");
    string name = lpName.ToString();
    string className = lpClass.ToString();

DllImport ERROR_MORE_DATA UNMANAGED在C＃中调用C ++

1 个答案: