调用Marshal.PtrToStructure

Question

我正在尝试从C＃调用一个非托管方法，它返回一个指向结构的指针。

该方法似乎返回一个值但是当我使用指针调用Marshal.PtrToStructure时，我得到一个访问冲突错误。

系统是Windows Server 2012 r2，我的代码和互操作编译为64位。

以下是IDL的签名：

typedef struct _tagCCatConfigInfo { 
        DWORD dwCCatConfigInfoFlags; 
        DWORD dwEnable; 
        DWORD dwCatFlags; 
        LPSTR pszRoutingType; 
        LPSTR pszBindDomain; 
        LPSTR pszUser; 
        LPSTR pszPassword; 
        LPSTR pszBindType; 
        LPSTR pszSchemaType; 
        LPSTR pszHost; 
        LPSTR pszNamingContext; 
        LPSTR pszDefaultDomain; 
        DWORD dwPort; 
        ISMTPServer *pISMTPServer; 
        ICategorizerDomainInfo *pIDomainInfo; 
        DWORD dwVirtualServerID; 
} CCATCONFIGINFO, *PCCATCONFIGINFO; 


interface ICategorizerParameters : IUnknown 
{ 
  HRESULT GetDSParameterA( 
          [in]  DWORD dwDSParameter, 
          [out] LPSTR *ppszValue); 

  HRESULT SetDSParameterA( 
          [in] DWORD dwDSParameter, 
          [in, unique] LPCSTR pszValue); 

  HRESULT RequestAttributeA( 
          [in, unique] LPCSTR pszName); 

  HRESULT GetAllAttributes( 
          [out] LPSTR **prgszAllAttributes); 

  HRESULT ReserveICatItemPropIds( 
          [in]  DWORD   dwNumPropIdsRequested, 
          [out] DWORD   *pdwBeginningPropId); 

  HRESULT ReserveICatListResolvePropIds( 
          [in]  DWORD   dwNumPropIdsRequested, 
          [out] DWORD   *pdwBeginningPropId); 

  HRESULT GetCCatConfigInfo( 
          [out] PCCATCONFIGINFO *ppCCatConfigInfo);od 
};

管理对手：

[StructLayout(LayoutKind.Sequential, Pack = 4)] 
  public struct _tagCCatConfigInfo 
  { 
    public uint dwCCatConfigInfoFlags; 
    public uint dwEnable; 
    public uint dwCatFlags; 

    [MarshalAs(UnmanagedType.LPStr)]                 
    public string pszRoutingType; 

    [MarshalAs(UnmanagedType.LPStr)] 
    public string pszBindDomain; 

    [MarshalAs(UnmanagedType.LPStr)] 
    public string pszUser; 

    [MarshalAs(UnmanagedType.LPStr)] 
    public string pszPassword; 

    [MarshalAs(UnmanagedType.LPStr)] 
    public string pszBindType; 

    [MarshalAs(UnmanagedType.LPStr)] 
    public string pszSchemaType; 

    [MarshalAs(UnmanagedType.LPStr)] 
    public string pszHost; 

    [MarshalAs(UnmanagedType.LPStr)] 
    public string pszNamingContext; 

    [MarshalAs(UnmanagedType.LPStr)] 
    public string pszDefaultDomain; 

    public uint dwPort; 

    [MarshalAs(UnmanagedType.Interface)] 
    public ISMTPServer pISMTPServer; 

    [MarshalAs(UnmanagedType.Interface)] 
    public ICategorizerDomainInfo pIDomainInfo; 

    public uint dwVirtualServerID; 
} 


[ComConversionLoss, Guid("86F9DA7B-EB6E-11D1-9DF3-00C04FA322BA"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)] 
[ComImport] 
public interface ICategorizerParameters 
{ 
  .... 
  .... 
  .... 

  [MethodImpl(MethodImplOptions.InternalCall)] 
  void GetCCatConfigInfo([Out] ref IntPtr ppCCatConfigInfo); 
}

我的托管呼叫代码：

void IMailTransportCategorize.ExpandItem(ICategorizerParameters pICatParms, ICategorizerItem pICatItem, IMailTransportNotify pINotify, IntPtr pvNotifyContext) 
{ 
  IntPtr ppCCatConfigInfo = IntPtr.Zero; 

  try 
  { 
    pICatParms.GetCCatConfigInfo(out ppCCatConfigInfo); 

    _tagCCatConfigInfo theStruct = (_tagCCatConfigInfo)Marshal.PtrToStructure(ppCCatConfigInfo, typeof(_tagCCatConfigInfo)); <-- Access violation 

  } 
  catch(exception ex) 
  } 
    Debug.WriteLine("Exception: {0}", ex.Message); 
  } 
  finally 
  { 
    if (null != pICatParms) { Marshal.ReleaseComObject(pICatParms); } 
    if (null != pICatItem) { Marshal.ReleaseComObject(pICatItem); } 
    if (null != pINotify) { Marshal.ReleaseComObject(pINotify); } 
  } 
}

这是我获取访问权限的地方

tagCCatConfigInfo theStruct = (_tagCCatConfigInfo)Marshal.PtrToStructure(ppCCatConfigInfo, typeof(_tagCCatConfigInfo))

系统崩溃，输出窗口显示 - 类型＆＃39; System.AccessViolationException＆＃39;的第一次机会异常。发生在mscorlib.dll中 错误日志没有任何异常条目，SMTP服务停止。

有什么想法吗？

由于 Al