ehlibmte.pas

ehlib31控件包

{*******************************************************}
{                                                       }
{                       EhLib vX.X                      }
{          Register object that sort data in            }
{                TCustomClientDataSet                   }
{                                                       }
{      Copyright (c) 2003 by Dmitry V. Bolshakov        }
{                                                       }
{*******************************************************}

{*******************************************************}
{ Add this unit to 'uses' clause of any unit of your    }
{ project to allow TDBGridEh to sort data in            }
{ TMemTableEh automatically after sorting markers       }
{ will be changed.                                      }
{ TMTEDatasetFeaturesEh determine if                    }
{ TDBGridEh.SortLocal = True then it will sort data     }
{ in memory using procedure SortByFields                }
{ else if SortLocal = False and MemTable connected to   }
{ other  DataSet via ProviderDataSet, it will try to    }
{ sord data in this DataSet using                       }
{ GetDatasetFeaturesForDataSet function                 }
{*******************************************************}

unit EhLibMTE;

{$I EhLib.Inc}

interface

uses
{$IFDEF EH_LIB_6} Variants, {$ENDIF}
  DbUtilsEh, DBGridEh, Db, MemTableEh, SysUtils;

type

  TMTEDatasetFeaturesEh = class(TDatasetFeaturesEh)
  public
    procedure ApplySorting(Sender: TObject; DataSet: TDataSet; IsReopen: Boolean); override;
  end;

implementation

uses Classes;

{ TMTEDatasetFeaturesEh }

procedure TMTEDatasetFeaturesEh.ApplySorting(Sender: TObject; DataSet: TDataSet; IsReopen: Boolean);
var
  DS: TDataSet;
  MTE: TCustomMemTableEh;
  DatasetFeatures: TDatasetFeaturesEh;
  i: Integer;
  OrderByStr: String;
begin
  if Sender is TCustomDBGridEh then
    if TCustomDBGridEh(Sender).SortLocal then
      with TCustomDBGridEh(Sender) do
        begin
          OrderByStr := '';
          for i := 0 to SortMarkedColumns.Count - 1 do
          begin
            OrderByStr := OrderByStr + SortMarkedColumns[i].FieldName + ' ';
            if SortMarkedColumns[i].Title.SortMarker = smUpEh then
              OrderByStr := OrderByStr + ' DESC';
            OrderByStr := OrderByStr + ',';
          end;
          Delete(OrderByStr, Length(OrderByStr), 1);
          if (DataSet is TCustomMemTableEh) then
          begin
            MTE := TCustomMemTableEh(DataSet);
            MTE.SortByFields(OrderByStr);
          end;
        end
    else
    begin
      if not (DataSet is TCustomMemTableEh) then Exit;
      DS := TCustomMemTableEh(DataSet).ProviderDataSet;
      if DS <> nil then
      begin
        DatasetFeatures := GetDatasetFeaturesForDataSet(DS);
        if DatasetFeatures <> nil then
          DatasetFeatures.ApplySorting(Sender, DS, False);
        DataSet.Close;
        DataSet.Open;
      end;
    end;
end;

initialization
  RegisterDatasetFeaturesEh(TMTEDatasetFeaturesEh, TCustomMemTableEh);
end.