Midas三层中，如何从客户端上传文件至服务器端？

Question

结构:Client(SocketConnection) + Server(RemoteDataModule ) + DataBase(sql server 2000)Midas三层中，如何从客户端上传文件至服务器端？

Answer 1

在APP当中添加一个方法，比如使用varByte Array作为参数类型，然后传递过去。这个在好多年前的老贴子当中就有了，网上众多资料都会提到，一些书上也会讲到。其实就是一个FileStream/Stream与Variant相互转换。

Answer 2

procedure TFilePacket.ReadFile(const FileName: WideString;
                               var Packet: OleVariant);
var
  TempStream:TFileStream;
  Param:OleVariant;
  p:Pointer;
begin
  TempStream:=TFileStream.Create(String(FileName),fmOpenRead);
  try
     Param:=VarArrayCreate([0,TempStream.Size-1],varByte);
     p:=VarArrayLock(Param);
     try
        TempStream.Position:=0;
        TempStream.Read(p^,TempStream.Size);
     finally
        VarArrayUnlock(Param);
     end;
  finally
     TempStream.Free;
  end;
  Packet:=Param;
end;function TFilePacket.WriteFile(var Stream: OleVariant;
                               const FileName: WideString): SYSINT;
var
  OutStream:TFileStream;
  p:Pointer;
begin
  Result:=-1;
  p:=VarArrayLock(Stream);
  OutStream:=TFileStream.Create(String(FileName),fmCreate);
  try
     OutStream.Write(p^,VarArrayHighBound(Stream,1)+1);
  finally
     VarArrayUnlock(Stream);
     OutStream.Free;
  end;
  Result:=0;
end;