我也在一个三层结构中使用到这个这一功能，以下是我实现的Parameter与流的转换
procedure ParamsToStream(Params: TParams; var Strm: TStream);
var
I: SmallInt;
PM: TParam;
prmName: string;
nSize: Integer;
ftp: TFieldType;
Pnt: Pointer;
begin
//写入ParamCount
nSize := Params.Count;
Strm.Write(nSize, SizeOf(nSize));
//获取Param
for I := 0 to Params.Count - 1 do
begin
PM := Params[I];
//写入参数名称
prmName := PM.Name;
nSize := Length(prmName);
Strm.Write(nSize, SizeOf(nSize));
Strm.Write(prmName[1], nSize);
//写入数据类型
ftp := PM.DataType;
Strm.Write(ftp, SizeOf(ftp));
//写入数据体
nSize := PM.GetDataSize;
Pnt := AllocMem(nSize);
PM.GetData(Pnt);
Strm.Write(nSize, SizeOf(nSize));
Strm.Write(Pnt^, nSize);
FreeMem(Pnt);
end;
Strm.Position := 0;
end;
procedure StreamToParams(Strm: TStream; Params: TParams);
var
I: SmallInt;
prmCount, nSize: Integer;
prmName: string;
prmType: TFieldType;
Pnt: Pointer;
PM: TParam;
begin
//读取Param总数
Strm.Position := 0;
Strm.Read(prmCount, SizeOf(prmcount));
//读取Param
for I := 0 to prmCount - 1 do
begin
//读取参数名称
Strm.Read(nSize, SizeOf(nSize));
SetLength(prmName, nSize);
Strm.Read(pchar(prmName)^, nSize);
//读取数据类型
Strm.Read(prmType, SizeOf(prmType));
//读取数据体
Strm.Read(nSize, SizeOf(nSize));
Pnt := AllocMem(nSize);
Strm.Read(Pnt^, nSize);
PM := Params.CreateParam(prmType, prmName, ptInput);
PM.SetData(Pnt);
FreeMem(Pnt);
end;
end; |
