Экспорт из TDBGrid в Excel без OLE

Delphi , Компоненты и Классы , TDBGrid

Автор: http://www.swissdelphicenter.ch

{
  Exporting a DBGrid to excel without OLE

  I develop software and about 95% of my work deals with databases.
  I enjoied the advantages of using Microsoft Excel in my projects
  in order to make reports but recently I decided to convert myself
  to the free OpenOffice suite.
  I faced with the problem of exporting data to Excel without having
  Office installed on my computer.
  The first solution was to create directly an Excel format compatible file:
  this solution is about 50 times faster than the OLE solution but there
  is a problem: the output file is not compatible with OpenOffice.
  I wanted a solution which was compatible with each "DataSet";
  at the same time I wanted to export only the dataset data present in
  a DBGrid and not all the "DataSet".
  Finally I obtained this solution which satisfied my requirements.
  I hope that it will be usefull for you too.

  First of all you must import the ADOX type library
  which will be used to create the Excel file and its
  internal structure: in the Delphi IDE:

  1)Project->Import Type Library:
  2)Select "Microsoft ADO Ext. for DDL and Security"
  3)Uncheck "Generate component wrapper" at the bottom
  4)Rename the class names (TTable, TColumn, TIndex, TKey, TGroup, TUser, TCatalog) in
    (TXTable, TXColumn, TXIndex, TXKey, TXGroup, TXUser, TXCatalog)
    in order to avoid conflicts with the already present TTable component.
  5)Select the Unit dir name and press "Create Unit".
    It will be created a file named AOX_TLB.
    Include ADOX_TLB in the "uses" directive inside the file in which you want
    to use ADOX functionality.

  That is all. Let's go now with the implementation:
 }

unit DBGridExportToExcel;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  ExtCtrls, StdCtrls, ComCtrls, DB, IniFiles, Buttons, dbgrids, ADOX_TLB, ADODB;

type
  TScrollEvents = class
    BeforeScroll_Event: TDataSetNotifyEvent;
    AfterScroll_Event: TDataSetNotifyEvent;
    AutoCalcFields_Property: Boolean;
  end;

procedure DisableDependencies(DataSet: TDataSet; var ScrollEvents:
  TScrollEvents);
procedure EnableDependencies(DataSet: TDataSet; ScrollEvents: TScrollEvents);
procedure DBGridToExcelADO(DBGrid: TDBGrid; FileName: string; SheetName:
  string);

implementation

//Support procedures: I made that in order to increase speed in
//the process of scanning large amounts
//of records in a dataset

//we make a call to the "DisableControls" procedure and then disable the "BeforeScroll" and
//"AfterScroll" events and the "AutoCalcFields" property.

procedure DisableDependencies(DataSet: TDataSet; var ScrollEvents:
  TScrollEvents);
begin
  with DataSet do
  begin
    DisableControls;
    ScrollEvents := TScrollEvents.Create();
    with ScrollEvents do
    begin
      BeforeScroll_Event := BeforeScroll;
      AfterScroll_Event := AfterScroll;
      AutoCalcFields_Property := AutoCalcFields;
      BeforeScroll := nil;
      AfterScroll := nil;
      AutoCalcFields := False;
    end;
  end;
end;

//we make a call to the "EnableControls" procedure and then restore
// the "BeforeScroll" and "AfterScroll" events and the "AutoCalcFields" property.

procedure EnableDependencies(DataSet: TDataSet; ScrollEvents: TScrollEvents);
begin
  with DataSet do
  begin
    EnableControls;
    with ScrollEvents do
    begin
      BeforeScroll := BeforeScroll_Event;
      AfterScroll := AfterScroll_Event;
      AutoCalcFields := AutoCalcFields_Property;
    end;
  end;
end;

//This is the procedure which make the work:

procedure DBGridToExcelADO(DBGrid: TDBGrid; FileName: string; SheetName:
  string);
var
  cat: _Catalog;
  tbl: _Table;
  col: _Column;
  i: integer;
  ADOConnection: TADOConnection;
  ADOQuery: TADOQuery;
  ScrollEvents: TScrollEvents;
  SavePlace: TBookmark;
begin
  //
  //WorkBook creation (database)
  cat := CoCatalog.Create;
  cat._Set_ActiveConnection('Provider=Microsoft.Jet.OLEDB.4.0; Data Source=' +
    FileName + ';Extended Properties=Excel 8.0');
  //WorkSheet creation (table)
  tbl := CoTable.Create;
  tbl.Set_Name(SheetName);
  //Columns creation (fields)
  DBGrid.DataSource.DataSet.First;
  with DBGrid.Columns do
  begin
    for i := 0 to Count - 1 do
      if Items[i].Visible then
      begin
        col := nil;
        col := CoColumn.Create;
        with col do
        begin
          Set_Name(Items[i].Title.Caption);
          Set_Type_(adVarWChar);
        end;
        //add column to table
        tbl.Columns.Append(col, adVarWChar, 20);
      end;
  end;
  //add table to database
  cat.Tables.Append(tbl);

  col := nil;
  tbl := nil;
  cat := nil;

  //exporting
  ADOConnection := TADOConnection.Create(nil);
  ADOConnection.LoginPrompt := False;
  ADOConnection.ConnectionString :=
    'Provider=Microsoft.Jet.OLEDB.4.0; Data Source=' + FileName +
    ';Extended Properties=Excel 8.0';
  ADOQuery := TADOQuery.Create(nil);
  ADOQuery.Connection := ADOConnection;
  ADOQuery.SQL.Text := 'Select * from [' + SheetName + '$]';
  ADOQuery.Open;

  DisableDependencies(DBGrid.DataSource.DataSet, ScrollEvents);
  SavePlace := DBGrid.DataSource.DataSet.GetBookmark;
  try
    with DBGrid.DataSource.DataSet do
    begin
      First;
      while not Eof do
      begin
        ADOQuery.Append;
        with DBGrid.Columns do
        begin
          ADOQuery.Edit;
          for i := 0 to Count - 1 do
            if Items[i].Visible then
            begin
              ADOQuery.FieldByName(Items[i].Title.Caption).AsString :=
                FieldByName(Items[i].FieldName).AsString;
            end;
          ADOQuery.Post;
        end;
        Next;
      end;
    end;

  finally
    DBGrid.DataSource.DataSet.GotoBookmark(SavePlace);
    DBGrid.DataSource.DataSet.FreeBookmark(SavePlace);
    EnableDependencies(DBGrid.DataSource.DataSet, ScrollEvents);

    ADOQuery.Close;
    ADOConnection.Close;

    ADOQuery.Free;
    ADOConnection.Free;

  end;

end;

end.

Статья Экспорт из TDBGrid в Excel без OLE раздела Компоненты и Классы TDBGrid может быть полезна для разработчиков на Delphi и FreePascal.

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