dynamicdatasetunit.pas

Delphi最新三层源码(1.0),对delphi有帮助

unit DynamicDataSetUnit;

interface

uses
  Windows, Classes, SysUtils, DB, DBClient, Variants;


  type
    TDynamicDataSet = Class(TPersistent)
      private
        //打包传给客户端的相关TDataSet信息.
      published
        procedure prepareTable(tmpDS: TDataSet); virtual;
        procedure InitOleFields(tmpDS: TDataSet);
        procedure CreateDataSet(tmpDS: TDataSet); virtual;
      public
        OleFields: OleVariant;
        OleFldName: OleVariant;
        OleFldType: OleVariant;
        OleFldSize: OleVariant;
        DataSet: TClientDataSet;
        
        constructor Create; virtual;
  end;


implementation

constructor TDynamicDataSet.Create;
begin
  inherited Create;
  DataSet := TClientDataSet.Create(nil);
  OleFields := VarArrayCreate([0,2], varVariant);
end;

procedure TDynamicDataSet.InitOleFields(tmpDS: TDataSet);
var
  i_i: Integer;
begin
  OleFldName := VarArrayCreate([0,tmpDS.FieldCount-1],varVariant);
  OleFldType := VarArrayCreate([0,tmpDS.FieldCount-1],varVariant);
  OleFldSize := VarArrayCreate([0,tmpDS.FieldCount-1],varVariant);
  for i_i:=0 to tmpDS.FieldCount-1 do
  begin
    OleFldName[i_i] := tmpDS.Fields[i_i].FieldName;
    OleFldType[i_i] := tmpDS.Fields[i_i].DataType;
    OleFldSize[i_i] := tmpDS.Fields[i_i].Size;
  end;
  OleFields[0] := OleFldName;
  OleFields[1] := OleFldType;
  OleFields[2] := OleFldSize;  
end;

procedure TDynamicDataSet.CreateDataSet(tmpDS: TDataSet);
var
  i_i: integer;
begin
  DataSet.FieldDefs.Clear;
  DataSet.Close;
  for i_i:=0 to tmpDS.FieldCount-1 do
  begin
    with DataSet.FieldDefs.AddFieldDef do
    begin
      Name := tmpDS.Fields[i_i].FieldName;
      DataType := tmpDS.Fields[i_i].DataType;
      Size := tmpDS.Fields[i_i].Size;
    end;
  end;
  DataSet.CreateDataSet;
  DataSet.Open;
end;

procedure TDynamicDataSet.prepareTable(tmpDS: TDataSet);
begin
  //赋值：
  InitOleFields(tmpDS);
  CreateDataSet(tmpDS);
end;

end.