求助一个很菜的问题！！ 关于使用VC编写读写数据库图片信息的错误

各位XDJM：我在仿照MSDN上的实例（参看：http://support.microsoft.com/kb/317017）想做一个能读写数据库图片的程序，但是编译时提示：fatal error C1021: invalid preprocessor command 'using'，指向的是这一行：“#using <mscorlib.dll>”  在网上找了下都没有该问题好的解释，各位能给下原因吗？ 或者谁能帮忙给份能够编译通过的实例参考下，本人刚学VC，多多包涵，谢谢！   #include "stdafx.h"
   #using <mscorlib.dll>
   #using <System.dll>
   #using <System.Data.dll>   using namespace System;
   using namespace System::Data;
   using namespace System::Data::SqlClient;
   using namespace System::Data::OleDb;
   using namespace System::IO;   // Prototypes for functions that do the actual work.
   void File2SqlBlob(String *);
   void File2OleDbBlob(String *);
   void SqlBlob2File(String *);
   void OleDbBlob2File(String *);   int direction(void);
   int reader (void);      // This is the entry point for the application.
   #ifdef _UNICODE
   int wmain(void)
   #else
   int main(void)
   #endif
   {
        // File you will create from database.
        String *DestFilePath = "c:\\mytest.bmp"; 
        // File you will insert into database.
        String *SourceFilePath = "C:\\pic\\Kevin Garnett.jpg";  // Insert BLOB into database from file using SQL provider.
File2SqlBlob(SourceFilePath);  // Insert BLOB into database from file using OleDb provider.
File2OleDbBlob(SourceFilePath); // Read BLOB from database into file using SQL provider.
SqlBlob2File(DestFilePath); // Read BLOB from database into file using OleDb provider.
        OleDbBlob2File(DestFilePath);     return 0;   
   }

   void SqlBlob2File(String *DestFilePath)
   {
try{
        // The column number of the BLOB field.
        int PictureCol = 0; 
SqlConnection *cn = new SqlConnection("server=localhost;integrated security=yes;database=NorthWind");
SqlCommand *cmd = new SqlCommand("SELECT Picture FROM Categories WHERE CategoryName='Test'", cn);
cn->Open(); // Create server-side DataReader to read BLOB from database.
SqlDataReader *dr  = cmd->ExecuteReader();
dr->Read(); // Create buffer for BLOB and read from DataReader. Close 
        // DataReader and Connection.
Byte b[] = __gc new  Byte[Convert::ToInt32((dr->GetBytes(PictureCol, 0, 0, 0, Int32::MaxValue)))];
dr->GetBytes(PictureCol, 0, b, 0, b->Length);
dr->Close();
cn->Close(); // Open FileStream and write buffer to file.
FileStream *fs = new FileStream(DestFilePath, FileMode::Create, FileAccess::Write);
fs->Write(b, 0, b->Length);
fs->Close(); Console::WriteLine("SqlBlob2File completed successfully.\nPress return to continue.");
Console::ReadLine();
}catch(SqlException *ex)
 {Console::Write(ex->Message);}
   }   void OleDbBlob2File(String *DestFilePath)
   {
try{
         // The column number of the BLOB field.
 int PictureCol = 0; 
OleDbConnection *cn = new OleDbConnection("provider=SQLOLEDB;server=localhost;user id=user;password=pass;database=NorthWind");
OleDbCommand *cmd = new OleDbCommand("SELECT Picture FROM Categories WHERE CategoryName='Test'", cn);
cn->Open(); // Create server-side DataReader to read BLOB from database.
OleDbDataReader *dr  = cmd->ExecuteReader();
dr->Read(); // Create buffer for BLOB and read from DataReader. Close 
        // DataReader and Connection.
Byte b[] = __gc new  Byte[Convert::ToInt32((dr->GetBytes(PictureCol, 0, 0, 0, Int32::MaxValue)))];
dr->GetBytes(PictureCol, 0, b, 0, b->Length);
dr->Close();
cn->Close(); // Open FileStream and write buffer to file.
FileStream *fs = new FileStream(DestFilePath, FileMode::Create, FileAccess::Write);
fs->Write(b, 0, b->Length);
fs->Close();
Console::WriteLine("OleDbBlob2File completed successfully.\nPress return to continue.");
}catch(OleDbException *ex)
 {Console::Write(ex->Message);}
   }
   void File2SqlBlob(String *SourceFilePath)
   {
try{
SqlConnection *cn = new SqlConnection("server=localhost;integrated security=yes;database=NorthWind");
// Create SQL command containing @Picture parameter for BLOB.
SqlCommand *cmd = new SqlCommand("UPDATE Categories SET Picture=@Picture WHERE CategoryName='Test'", cn);

// Read FileStream into buffer and then close stream.
FileStream *fs = new FileStream(SourceFilePath, FileMode::Open, FileAccess::Read);
int size = Convert::ToInt32(fs->Length);
Byte b[] = __gc new  Byte[size];
fs->Read(b, 0, size);
fs->Close(); // Create parameter for the @Picture contained in SQL statement.
SqlParameter *P = new SqlParameter("@Picture", SqlDbType::VarBinary, b->Length, ParameterDirection::Input, false, 0, 0, 0, DataRowVersion::Current, b);
cmd->Parameters->Add(P); // Open connection, execute query, and close connection.
cn->Open();
if (cmd->ExecuteNonQuery() == 1)
cn->Close(); Console::WriteLine("File2SqlBlob completed successfully.\nPress return to continue.");
Console::ReadLine();
}catch(SqlException *ex)
 {Console::Write(ex->Message);}
   }   void File2OleDbBlob(String *SourceFilePath)
   {
try{
OleDbConnection *cn = new OleDbConnection("provider=SQLOLEDB;user id=user;password=pass;database=NorthWind");
// Create SQL command containing ? parameter for BLOB.
OleDbCommand *cmd = new OleDbCommand("UPDATE Categories SET Picture=? WHERE CategoryName='Test'", cn);

// Read FileStream into buffer and then close stream.
FileStream *fs = new FileStream(SourceFilePath, FileMode::Open, FileAccess::Read);
int size = Convert::ToInt32(fs->Length);
Byte b[] = __gc new  Byte[size];
fs->Read(b, 0, size);
fs->Close();

// Create parameter for the ? contained in the SQL statement.
OleDbParameter *P = new OleDbParameter("@Picture", OleDbType::VarBinary, b->Length, ParameterDirection::Input, false, 0, 0, 0, DataRowVersion::Current, b);
cmd->Parameters->Add(P);

// Open connection, execute query, and close connection.
cn->Open();
if (cmd->ExecuteNonQuery() == 1)
cn->Close(); Console::WriteLine("File2OleDbBlob completed successfully.\nPress return to continue.");
Console::ReadLine();
}catch(OleDbException *ex)
 {Console::Write(ex->Message);}
   }