Regular expressions (Delphi)

Note

This demo is available in your FlexCel installation at <FlexCel Install Folder>\Demo\Delphi\Modules\20.Reports\47.Regular Expressions In Reports and also at https:​//​github.​com/​tmssoftware/​TMS-​FlexCel.​VCL-​demos/​tree/​master/​Delphi/​Modules/​20.​Reports/​47.​Regular Expressions In Reports

Overview

Regular expressions give you both the power to transform the text in your reports in any way you like, and also to obfuscate and make unmaintainable your templates if you abuse them. The <#regex()> tag lets you write your own Regular Expressions in a FlexCel report.

Concepts

• There are 2 versions of the <#regex> tag:

• RegEx(IgnoreCase, Expression, Search): This will search for the expression inside "Search" string, and return the part of "Search" that matches the expression.

• RegEx(IgnoreCase, Expression, Search, Replace): This will Replace the matching string inside "Search" by the "Replace" string.

• Both "Search" and "Replace" parameters are evaluated at runtime, so they will evaluate to different strings as the row changes. The "Expression" parameter is evaluated only once before starting the report, so it will not change.

• As formerly said, use regular expressions with care. Sometimes they are just invaluable to get your desired output, but on other times they can make maintaining the templates a lot of work. Depending on the case, you might find better to define your own user function to do a complex transformation. (See the User Defined Functions example)

• Regular Expressions are a complex subject, and we will not explain how to use them here. There is a lot of information out there available on them.

Files

UMainForm.pas

unit UMainForm;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics,
  FlexCel.VCLSupport, FlexCel.Core, FlexCel.XlsAdapter, FlexCel.Report, FlexCel.Render,
  {$if CompilerVersion >= 23.0} System.UITypes, {$IFEND}
  ShellApi,
  Controls, Forms, Dialogs, StdCtrls, ExtCtrls;

type
  TMainForm = class(TForm)
    btnCancel: TButton;
    btnGo: TButton;
    SaveDialog: TSaveDialog;
    Label1: TLabel;
    procedure btnCancelClick(Sender: TObject);
    procedure btnGoClick(Sender: TObject);
  private
    procedure RunReport;
    function GetDataPath: string;
    { Private declarations }
  public
    { Public declarations }
  end;

var
  MainForm: TMainForm;

implementation
uses IOUtils, DemoData;

{$R *.dfm}

procedure TMainForm.btnCancelClick(Sender: TObject);
begin
  Close;
end;

procedure TMainForm.btnGoClick(Sender: TObject);
begin
  RunReport;

end;

function TMainForm.GetDataPath: string;
begin
  Result := TPath.Combine(TPath.GetDirectoryName(ParamStr(0)), '..\..');
end;


procedure TMainForm.RunReport;
var
  Report: TFlexCelReport;
begin
  if not SaveDialog.Execute then exit;

  Report := TFlexCelReport.Create(true);
  try
    Report.AddTable(DemoTables);
    Report.SetValue('Date', Now);
    Report.SetValue('ReportCaption', 'Suppliers');
    Report.Run(
      TPath.Combine(GetDataPath, 'Regular Expressions In Reports.template.xls'),
      SaveDialog.FileName);
  finally
    Report.Free;
  end;

  if MessageDlg('Do you want to open the generated file?', mtConfirmation, [mbYes, mbNo], 0) = mrYes then
  begin
    ShellExecute(0, 'open', PCHAR(SaveDialog.FileName), nil, nil, SW_SHOWNORMAL);
  end;


end;

end.