MIDAS中传递自定义结构体

MIDAS中不可以传递自定义的结构体,或者数据流之类的.可以借助Variant来实现这一功能.

//将VarArray转换成结构体,这种转换只需要设计接口时传回Variant和Rec的Size就可以了.

procedure  VarAryToRec(aVar: Variant; const Size:Integer; var Rec);
var
  pb: PByteArray;
  i: Integer;
begin
  FillChar(Rec, Size, 0);
  pb := @Rec;
  for i := 0 to Size - 1 do begin
    Pb^[i] := aVar[i];
  end;
end;

//将结构体转换成VarAry,这种转换需要先建立一个VarAry,然后再通过接口传递.

procedure RecToVarAry(const Rec; const Size: Integer;var aVar:Variant);
var
  pb: PByteArray;
  i: Integer;
begin
    pb := @Rec;
    for i := 0 to Size -1 do begin
      aVar[i] := pb^[i];
    end;
end;

//Client调用示例

var
  aVar: Variant;
  Size: Integer;
  Done: Integer;

begin

  Size := SizeOf(Rec);
  aVar := VarArrayCreate([0, Size - 1], varByte);
  try
    RecToVarAry(Rec, Size, aVar);
    SocketConnection.AppServer.InserDataRecord(Size, aVar, Done);
    if not Boolean(Done) then
      Exit;
    DataIndex := Done;
  finally
    aVar := Unassigned;
  end;

end;

//服务器端示例,这个接口需要在IAppServer中设计好.

procedure TAppSer.InserDataRecord(Size: Integer; Data: OleVariant;
  out Done: Integer);
var
  Rec: TSampleDataRecord;
  n: Integer;
begin
  Done := -1;
  if not ADOConnection.Connected then
    Exit;
  VarAryToRec(Data, Size, Rec);
 //...........

end;