Example Delphi

Change TDBGrid Row Height

admin — Tue, 23 Feb 2010 22:11:19 +0000

Examples that we will make here is about the TDBGrid Row height settings. If we want to change our DBGrid display by adding or reducing the high DBGrid row, can be done in the following ways:

To make this example we need a component TDBGrid, TButton and TEdit on Form1. Button1 will be used to trigger changes to high DBGrid with Edit1 lines as input.
Please set DBGrid to connect with the tables from the database. In the example I gave I use the table from the database DEMODATA Department.
Use this following code.

Here is the source code. If you want to download the source code examples, please click Here

unit Unit1;
 
interface
 
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, Grids, DBGrids, DB, ADODB, ExtCtrls;
 
type
  TForm1 = class(TForm)
    DBGrid1: TDBGrid;
    DataSource1: TDataSource;
    ADOConnection1: TADOConnection;
    ADODataSet1: TADODataSet;
    Panel1: TPanel;
    Button1: TButton;
    Edit1: TEdit;
    procedure Button1Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
 
  TMyDBGrid = class(TDBGrid)
  public
    property DefaultRowHeight;
  end;
 
var
  Form1: TForm1;
 
implementation
 
{$R *.dfm}
 
procedure TForm1.Button1Click(Sender: TObject);
begin
  DBGrid1.DataSource.DataSet.DisableControls;
  TStringGrid(DBGrid1).DefaultRowHeight := StrToIntDef(Edit1.Text,10);
  DBGrid1.DataSource.DataSet.EnableControls;
end;
 
procedure TForm1.FormCreate(Sender: TObject);
begin
  DbGrid1.Canvas.Font.Size := 13;
  TMyDBGrid(DBGrid1).DefaultRowHeight := DBGrid1.Canvas.TextHeight('MMMMM') + 4;
end;
 
end.

Related Examples

Delphi How to Get Computer Name

admin — Wed, 12 Aug 2009 07:27:03 +0000

The title is explain what we want to do right now. Yes, this is a delphi example how we can get the windows computer name with delphi application. This simple application need a TButton and a TEdit component. When we click the button the computer name fill the edit box.

Here's the code:

unit Unit1;
 
interface
 
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;
 
type
  TForm1 = class(TForm)
    Button1: TButton;
    Edit1: TEdit;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
 
var
  Form1: TForm1;
 
implementation
 
{$R *.dfm}
 
function GetComputerName: string;
var
  buffer: array[0..MAX_COMPUTERNAME_LENGTH + 1] of Char;
  Size: Cardinal;
begin
  Size := MAX_COMPUTERNAME_LENGTH + 1;
  Windows.GetComputerName(@buffer, Size);
  Result := StrPas(buffer);
end;
 
procedure TForm1.Button1Click(Sender: TObject);
begin
  Edit1.Text := GetComputerName;
end;
 
end.

Related Examples

Delphi How to Create DLL Contains a Form

admin — Wed, 12 Aug 2009 03:47:55 +0000

In this delphi example tutorial i want to show you how we can make a Dynamic Link Library (DLL) application that contain a form. So when we call a function declared in this DLL then it will show a form. In that case we need to create two project: a DLL project and a project to call the DLL function or procedure.

The DLL Project

Creating a DLL file we can go using a DLL Wizard located at File > New > Other menus.

Delphi the gives us a default DLL template like this:

library showformdll;
 
{ Important note about DLL memory management: ShareMem must be the
  first unit in your library's USES clause AND your project's (select
  Project-View Source) USES clause if your DLL exports any procedures or
  functions that pass strings as parameters or function results. This
  applies to all strings passed to and from your DLL--even those that
  are nested in records and classes. ShareMem is the interface unit to
  the BORLNDMM.DLL shared memory manager, which must be deployed along
  with your DLL. To avoid using BORLNDMM.DLL, pass string information
  using PChar or ShortString parameters. }
 
uses
  SysUtils,
  Classes,
  Unit1 in 'Unit1.pas' {Form1};
 
{$R *.res}
 
begin
end.

OK Let it like the original template first, know we need to create a form unit. Create a form unit from File > New > Form Menus. Now we have Project1 with Unit1.
Ok now back to the project1. Add this code below to create a procedure to open Form1 in unit1 then Export the procedure.

library showformdll;
 
{ Important note about DLL memory management: ShareMem must be the
  first unit in your library's USES clause AND your project's (select
  Project-View Source) USES clause if your DLL exports any procedures or
  functions that pass strings as parameters or function results. This
  applies to all strings passed to and from your DLL--even those that
  are nested in records and classes. ShareMem is the interface unit to
  the BORLNDMM.DLL shared memory manager, which must be deployed along
  with your DLL. To avoid using BORLNDMM.DLL, pass string information
  using PChar or ShortString parameters. }
 
uses
  SysUtils,
  Classes,
  Unit1 in 'Unit1.pas' {Form1};
 
{$R *.res}
 
Procedure ShowForm(Atitle:String);stdcall;
begin
  form1 := TForm1.Create(nil);
  try
    form1.Caption := Atitle;
    Form1.ShowModal;
  except
 
  end;
end;
 
Exports
  ShowForm;
 
begin
end.

ShowForm procedure is a procedure to open Form1. Save the project as "showformdll" than compile it. This will produce "showformdll.dll".

The Caller
After create the DLL than we need to create a small application to call ShowForm procedure declared in showformdll. Just create a simple application from File > New > Application menus then put a button to call the procedure.

Code is as simply like this:

Procedure ShowForm(Atitle:string);stdcall;external 'showformdll.DLL';
 
procedure TForm1.Button1Click(Sender: TObject);
begin
   ShowForm('This is a Form in DLL');
end;

Save this project as "DLLCaller" for example then it will create "DLLCaller.exe" when compiled. Now you can test your application. When Show Form button clicked, then we will see this form.

You can download the delphi example code here:http://www.mediafire.com/file/tkqdbtanl5z/dll-form.rar

Related Examples

Zoom a Stringgrid

admin — Wed, 27 May 2009 06:01:49 +0000

In this delphi example tutorial we will make an application contain a Stringgrid (TStringgrid) and two Button (TButton). The Stringgrid will be enable for zooming in and zooming out. Firt button will execute a procedure for Zoom In and the other one will execute Zoom Out Procedure. Here the screenshot:

And this is the code:

unit Unit1;
 
interface
 
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, Grids, StdCtrls;
 
type
  TForm1 = class(TForm)
    StringGrid1: TStringGrid;
    Button1: TButton;
    Button2: TButton;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
 
var
  Form1: TForm1;
 
implementation
 
{$R *.dfm}
 
procedure ZoomGrid(AStringgrid:TStringGrid;level:Real);
var
  i:integer;
begin
  for i := 0 to AStringgrid.colcount - 1 do
    AStringgrid.colwidths[i] := round(AStringgrid.colwidths[i] * level);
 
  for i := 0 to AStringgrid.RowCount - 1 do
    AStringgrid.rowheights[i] := round(AStringgrid.rowheights[i] * level);
 
  AStringgrid.Font.Size := round(AStringgrid.rowheights[0] * 0.65);
end;
 
procedure TForm1.Button1Click(Sender: TObject);
begin
  ZoomGrid(StringGrid1,1.1);
end;
 
procedure TForm1.Button2Click(Sender: TObject);
begin
  ZoomGrid(StringGrid1,0.9);
end;
 
end.

Related Examples

Copy Stringgrid Cell’s Content to a Memo

admin — Wed, 27 May 2009 01:58:46 +0000

In this Delphi example we will make a simple application where it contain a Stringgrid (TStringGrid), a Button (TButton) and a Memo (TMemo). Button "Copy" used to copy a text string from selection cell in stringgrid. Below is the screenshot fo this application:

and this is the code:

unit Unit1;
 
interface
 
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls, Grids;
 
type
TForm1 = class(TForm)
StringGrid1: TStringGrid;
Memo1: TMemo;
Button1: TButton;
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
 
var
Form1: TForm1;
 
implementation
 
{$R *.dfm}
 
procedure TForm1.Button1Click(Sender: TObject);
var
str_from_grid:string;
begin
str_from_grid := StringGrid1.Cells[StringGrid1.Col,StringGrid1.Row];
if Length(str_from_grid) > 1 then
Memo1.Lines.Add(str_from_grid) ;
end;
 
end.

Related Examples

Take a Property Value From Many Object with As Operator

admin — Fri, 01 Aug 2008 10:53:36 +0000

 
//This is how we can Take a property value from many Object with As Operator
// Form this example we need 5 RadioButton1 to RadioButton5(TRadioButton) placed on Form1
//The we make GetRadioButtonCaption Function to be called by clicking each of RadioButton
//On Click event of each TRadioButton call this GetRadioButtonCaption Function
 
unit Unit1;
 
interface
 
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;
 
type
  TForm1 = class(TForm)
    RadioButton1: TRadioButton;
    RadioButton2: TRadioButton;
    RadioButton3: TRadioButton;
    RadioButton4: TRadioButton;
    RadioButton5: TRadioButton;
    procedure RadioButton1Click(Sender: TObject);
    procedure RadioButton2Click(Sender: TObject);
    procedure RadioButton3Click(Sender: TObject);
    procedure RadioButton4Click(Sender: TObject);
    procedure RadioButton5Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
 
var
  Form1: TForm1;
 
implementation
 
{$R *.dfm}
 
function GetRadioButtonCaption(Sender: TObject):String;
begin
  Result :=(Sender as TRadioButton).Caption;
end;
 
procedure TForm1.RadioButton1Click(Sender: TObject);
begin
  Showmessage(GetRadioButtonCaption(Sender));
end;
 
procedure TForm1.RadioButton2Click(Sender: TObject);
begin
 Showmessage(GetRadioButtonCaption(Sender));
end;
 
procedure TForm1.RadioButton3Click(Sender: TObject);
begin
  Showmessage(GetRadioButtonCaption(Sender));
end;
 
procedure TForm1.RadioButton4Click(Sender: TObject);
begin
  Showmessage(GetRadioButtonCaption(Sender));
end;
 
procedure TForm1.RadioButton5Click(Sender: TObject);
begin
  Showmessage(GetRadioButtonCaption(Sender));
end;
 
end.

Other Examples

Open A Password Protected Access Database with TOpenDialog

admin — Fri, 13 Jun 2008 03:34:05 +0000

//This is how we can open a password protected access database with TOpenDialog
//For this example we need Button1 and Button2 (TButton), Edit1 and Edit2 (TEdit) and also AdoConnection1 (TAdoConnection)
//Button1 is used to open access database file
//Edit2 is used for access database password
//Button2 is used to open connection
 
unit Unit1;
 
interface
 
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, DB, ADODB;
 
type
  TForm1 = class(TForm)
    Button1: TButton;
    Edit1: TEdit;
    ADOConnection1: TADOConnection;
    Edit2: TEdit;
    OpenDialog1: TOpenDialog;
    Button2: TButton;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
 
var
  Form1: TForm1;
 
implementation
 
{$R *.dfm}
 
procedure TForm1.Button1Click(Sender: TObject);
begin
  if OpenDialog1.Execute then
  begin
    Edit1.Text := OpenDialog1.FileName;
  end;
end;
 
procedure TForm1.Button2Click(Sender: TObject);
begin
    ADOConnection1.Close;
    ADOConnection1.ConnectionString := 'Provider=Microsoft.Jet.OLEDB.4.0;Data ' +
      'Source='+Edit1.Text+';Mode=ReadWrite;Persist ' +
      'Security Info=False;Jet OLEDB:Database Password='+Edit2.Text;
    Edit1.Text := OpenDialog1.FileName;
    try
      ADOConnection1.Open;
      if ADOConnection1.Connected = true then
        showmessage('Connected Sccessfull to '+Edit1.Text);
    except
      showmessage('Connection to '+Edit1.Text+' failed');
    end
end;
 
end.

Related Examples

Bitmap Operation for JPEG or JPG Image

admin — Mon, 12 May 2008 06:51:14 +0000

//This is how we can operate any Bitmap Operation to our JPEG image
//To make a bitmap operation in JPEG Image, first we need to convert JPEG Image to bitmap
//Then run any bitmap operation on convert result bitmap
//Then assign JPEG result from operated bitmap
//For this example we use convert to grayscale bitmap operation
//Use Button1(TButton) and OpenDialog1(TOpenDialog) for this example
 
unit Unit1;
 
interface
 
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;
 
type
  TForm1 = class(TForm)
    Button1: TButton;
    OpenDialog1: TOpenDialog;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
 
var
  Form1: TForm1;
 
implementation
 
uses
  jpeg;
 
{$R *.dfm}
 
function ConvertBitmapToGrayscale(const Bitmap: TBitmap): TBitmap;
var
  i, j: Integer;
  Grayshade, Red, Green, Blue: Byte;
  PixelColor: Longint;
begin
  with Bitmap do
    for i := 0 to Width - 1 do
      for j := 0 to Height - 1 do
      begin
        PixelColor := ColorToRGB(Canvas.Pixels[i, j]);
        Red        := PixelColor;
        Green      := PixelColor shr 8;
        Blue       := PixelColor shr 16;
        Grayshade  := Round(0.3 * Red + 0.6 * Green + 0.1 * Blue);
        Canvas.Pixels[i, j] := RGB(Grayshade, Grayshade, Grayshade);
      end;
  Result := Bitmap;
end;
 
procedure ConvertToBitmap(Source : TGraphic; Bitmap : TBitmap);
begin
 try
  if Bitmap = nil then
    Bitmap := TBitmap.Create
  else Bitmap.FreeImage;
  Bitmap.Width := Source.Width;
  Bitmap.Height := Source.Height;
  Bitmap.Canvas.Draw(0,0,Source);
 except
   showmessage('No Loaded File');
 end;
end;
 
procedure TForm1.Button1Click(Sender: TObject);
var
  MyJpeg,OperatedJpeg:TJPEGImage;
  MyBitmap,OperatedBitmap:TBitmap;
begin
  if OpenDialog1.Execute then
  begin
    MyJpeg        := TJPEGImage.Create;
    MyBitmap      := TBitmap.Create;
    OperatedBitmap := TBitmap.Create;
    OperatedJpeg   :=  TJPEGImage.Create;
    try
      MyJpeg.LoadFromFile(OpenDialog1.FileName);
      ConvertToBitmap(MyJpeg,MyBitmap);
      // Do any Bitmap Operation Here
      //For Example i Convert Bitmap To GrayScale and perform result into
      //operateBitmap
      OperatedBitmap := ConvertBitmapToGrayscale(MyBitmap);
      //Perform operated bitmap into jpeg
      OperatedJpeg.Assign(OperatedBitmap);
      OperatedJpeg.SaveToFile(OpenDialog1.FileName+'-Gray.jpeg');
      Showmessage('Operation Completed')
    finally
      MyJpeg.Free;
      OperatedJpeg.Free;
    end;
  end;
end;
 
end.

Related Examples

Play a Wav Sound Without TMediaPlayer

admin — Wed, 07 May 2008 09:51:25 +0000

//This is we can play a WAV file without TMediaPlayer Component
//Using PlaySound Function declared in mmsystem unit
//So you must add mmsystem in uses clause
 
unit Unit1;
 
interface
 
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, ComCtrls, MPlayer, StdCtrls;
 
type
  TForm1 = class(TForm)
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
 
var
  Form1: TForm1;
 
implementation
 
{$R *.dfm}
 
uses
  mmsystem;
 
procedure TForm1.Button1Click(Sender: TObject);
begin
   PlaySound(PChar('C:\WINDOWS\Media\Windows XP Startup.wav'),0,SND_ASYNC)
end;
 
end.

Other Examples

Delete a Directory

admin — Tue, 06 May 2008 11:52:49 +0000

//This is how we can delete a directory
//DelDir Function originally wrote by Rainer Kümmerle (http://www.thinklazy.de)
//Put a Button1(Tbutton) then use this code
//Make a directory named 'DeletedDir' in your application path to be tested
 
unit Unit1;
 
interface
 
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;
 
type
  TForm1 = class(TForm)
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
 
var
  Form1: TForm1;
 
implementation
 
{$R *.dfm}
 
uses
  ShellApi;
 
function DelDir(dir: string): Boolean;
var
  fos: TSHFileOpStruct;
begin
  ZeroMemory(@fos, SizeOf(fos));
  with fos do
  begin
    wFunc  := FO_DELETE;
    fFlags := FOF_SILENT or FOF_NOCONFIRMATION;
    pFrom  := PChar(dir + #0);
  end;
  Result := (0 = ShFileOperation(fos));
end;
 
procedure TForm1.Button1Click(Sender: TObject);
begin
  ShowMessage(ExtractFilePath(Application.ExeName)+'DeletedDir');
  if DelDir(ExtractFilePath(Application.ExeName)+'DeletedDir')=true then
    ShowMessage(ExtractFilePath(Application.ExeName)+'DeletedDir'+' ' +
      'succesfully deleted')
  else
    ShowMessage('Delete Failed');
end;
 
end.