TDataSetRefresh (Delphi)

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Description

The following example sets a range for a dataset. The form requires two edit boxes, a data source, a client dataset or table, a db grid, and a button. Make sure that the Table1 info in FormActivate agrees with the table used. Also, the caption for the button must be initialized to '&ApplyRange'.

Code

procedure TForm1.FormActivate(Sender: TObject);
begin
  Table1.DatabaseName := 'DBDEMOS';
  Table1.TableName := 'CustInfo';
  Table1.Active := True;
  Table1.IndexName := '';
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
  if Button2.Caption = '&Apply Range' then
    begin
      Table1.SetRange([Edit1.Text],[Edit2.Text]);
      Button2.Caption := '&Drop Range';
    end
  else
    begin
      Table1.CancelRange;
      Table1.Refresh;
      Button2.Caption := '&Apply Range';
    end;
end;

procedure TForm1.FormCreate(Sender: TObject);
var
  i: Integer;
begin
  Table1:= TTable.Create(Form1);
  with Table1 do
  begin
    DatabaseName := 'DBDEMOS';
    TableType := ttParadox;
    TableName := 'CustInfo';
    Table1.Active := False;
    { Do not overwrite an existing table. }
    if Table1.Exists then
      MessageDlg('CustInfo table already exists.', mtWarning, [mbOK], 0)
    else
    begin
      { The Table component must not be active. }
      { First, describe the type of table and give }
      { it a name. }
      { Next, describe the fields in the table. }
      with FieldDefs do
      begin
        Clear;
        with AddFieldDef do
        begin
          Name := 'Field1';
          DataType := ftInteger;
          Required := True;
        end;
        with AddFieldDef do
        begin
          Name := 'Field2';
          DataType := ftString;
          Size := 30;
        end;
      end;
      { Next, describe any indexes. }
      with IndexDefs do
      begin
        Clear;
        { The first index has no name because it is
        { a Paradox primary key. }
        with AddIndexDef do
        begin
          Name := '';
          Fields := 'Field1';
          Options := [ixPrimary];
        end;
        with AddIndexDef do
        begin
          Name := 'Fld2Indx';
          Fields := 'Field2';
          Options := [ixCaseInsensitive];
        end;
      end;
      { Call the CreateTable method to create the table. }
      CreateTable;
      Table1.Active:= True;
      for i := 1 to 20 do
        Table1.AppendRecord([i*111, i*222]);
    end;
  end;
  DS2.DataSet:= Table1;
  DBGrid2.DataSource.DataSet:= Table1;
  Table1.Active:= False;
end;

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