Delphi Tutorial » Delphi Tutorial

Check If The BDE Is Installed

Delphi Tutorial — Sun, 02 Sep 2007 10:39:11 +0000

You can use this tip to check if the Borland Database Engine (BDE) is installed.

function isbdepresent: boolean;

var

IdapiPath: array[0..255] of Char;

IdapiHandle: THandle;

begin

result := false;

GetProfileString(‘IDAPI’, ‘DLLPath’, ‘C:’, IdapiPath, 255);

{next lines isolates the first directory path from the IdapiPath in case

there are more}

if Pos(‘;’, StrPas(IdapiPath)) <> 0 then

begin

StrPCopy(IdapiPath, Copy(StrPas(IdapiPath), 1, Pred(Pos(‘;’,

StrPas(IdapiPath)))));

end;

IdapiHandle := LoadLibrary(StrCat(IdapiPath, ‘IDAPI01.DLL’));

if IdapiHandle < HINSTANCE_ERROR then

result := false

{IDAPI is not present on this system}

else

begin

FreeLibrary(IdapiHandle);

result := true;

{IDAPI is present on this system}

end;

end;

How to Create Rounded Form

Delphi Tutorial — Wed, 07 Mar 2007 14:14:15 +0000

How to Create Rounded Form

procedure TForm1.FormCreate(Sender: TObject);
var
f : HRGN;
begin
Form1.Borderstyle := bsNone;
f := CreateRoundRectRgn(
0, // x-coordinate of the region’s upper-left corner
0, // y-coordinate of the region’s upper-left corner
clientwidth, // x-coordinate of the region’s lower-right corner
clientheight, // y-coordinate of the region’s lower-right corner
40, // height of ellipse for rounded corners
40); // width of ellipse for rounded corners
SetWindowRgn(Handle,f,True);
end;

Download: Source Code

How to Create a Gradient Filled Form

Delphi Tutorial — Fri, 02 Mar 2007 13:57:06 +0000

You can create a gradient filled form to make form that is more beautiful.

procedure TForm1.FormPaint(Sender: TObject);
var
Row, Ht: Word;
begin
Ht := (ClientHeight + 255) div 256;
for Row := 0 to 255 do
with Canvas do
begin
Brush.Color := RGB(Row, 100, 0);
FillRect(Rect(0, Row*Ht, ClientWidth, (Row+1) * Ht));
end;
end;

You can change the value of (Row, 100, 0) to suite your preferences.

Example:

(Row, 255, 0) or (Row, 100, 255)

Download: Source Code

Get Volume Name

Delphi Tutorial — Thu, 22 Feb 2007 06:53:02 +0000

This function used to get volume name.

function VolumeName(DriveName: Char): string;
var
max, Flags: DWORD;
Buf: array [0..MAX_PATH] of Char;
begin
try
GetVolumeInformation(PChar(DriveName + ‘:\’), Buf, sizeof(Buf), nil, max, Flags, nil, 0);
Result := StrPas(buf);
except
result := ”;
end;
end;

procedure TForm1.BitBtn1Click(Sender: TObject);
begin
Edit1.Text := VolumeName(‘C’);
end;

Download: Source Code

Get Start Menu Directory

Delphi Tutorial — Thu, 22 Feb 2007 06:17:44 +0000

This function used to get start menu directory.

uses shlobj;

function GetStartMenu: String;
var
dir: PItemIDList;
startmenu : array[0..MAX_PATH] of Char;
begin
SHGetSpecialFolderLocation(Application.handle, CSIDL_STARTMENU, dir);
SHGetPathFromIDList(dir, startmenu);
result := strpas(startmenu);
end;

procedure TForm1.BitBtn1Click(Sender: TObject);
begin
Edit1.Text := GetStartMenu;
end;

Download: Source Code

Get Windows Temporary Folder

Delphi Tutorial — Tue, 20 Feb 2007 07:02:38 +0000

If you need to get windows temporary folder for your application you need to follow this steps.

function GetTempDirectory: String;
var
TempDir: array[0..255] of Char;
begin
GetTempPath(255, @TempDir);
Result := StrPas(TempDir);
end;

procedure TForm1.BitBtn1Click(Sender: TObject);
begin
label1.Caption := gettempdirectory;
end;
Download Source Code

Empty Recycle Bin

Delphi Tutorial — Tue, 20 Feb 2007 06:53:43 +0000

Procedure to empty recycle bin

Procedure EmptyRecycleBin ;
Const
SHERB_NOCONFIRMATION = $00000001 ;
SHERB_NOPROGRESSUI = $00000002 ;
SHERB_NOSOUND = $00000004 ;
Type
TSHEmptyRecycleBin = function (Wnd : HWND;
pszRootPath : PChar;
dwFlags : DWORD
) : HRESULT; stdcall ;
Var
SHEmptyRecycleBin : TSHEmptyRecycleBin;
LibHandle : THandle;
Begin { EmptyRecycleBin }
LibHandle := LoadLibrary(PChar(‘Shell32.dll’)) ;
if LibHandle <> 0 then
@SHEmptyRecycleBin := GetProcAddress(LibHandle, ‘SHEmptyRecycleBinA’)
else
begin
MessageDlg(‘Failed to load Shell32.dll.’, mtError, [mbOK], 0);
Exit;
end;

if @SHEmptyRecycleBin <> nil then
SHEmptyRecycleBin(Application.Handle,
nil,
SHERB_NOCONFIRMATION or SHERB_NOPROGRESSUI or SHERB_NOSOUND);
FreeLibrary(LibHandle);
@SHEmptyRecycleBin := nil ;
end; { EmptyRecycleBin }

Show deleted records

Delphi Tutorial — Sat, 17 Feb 2007 05:55:49 +0000

With this procedure we can show deleted record from paradox table.

procedure deletedrecords(Table: TTable; SioNo: Boolean);
begin
Table.DisableControls;
try
Check(DbiSetProp(hDBIObj(Table.Handle), curSOFTDELETEON,
LongInt(SioNo)));
finally
Table.EnableControls;
end;
Table.Refresh;
end;

Hide the titlebar

Delphi Tutorial — Fri, 16 Feb 2007 06:45:32 +0000

Hide the titlebar.

Procedure TForm1.HideTitlebar;
var
Save : LongInt;
Begin
If BorderStyle=bsNone then Exit;
Save:=GetWindowLong(Handle,gwl_Style);
If (Save and ws_Caption)=ws_Caption then Begin
Case BorderStyle of
bsSingle,
bsSizeable : SetWindowLong(Handle,gwl_Style,Save and
(Not(ws_Caption)) or ws_border);
bsDialog : SetWindowLong(Handle,gwl_Style,Save and
(Not(ws_Caption)) or ds_modalframe or ws_dlgframe);
End;
Height:=Height-getSystemMetrics(sm_cyCaption);
Refresh;
End;
end;
And here is how we show it again:
Procedure TForm1.ShowTitlebar;
Var
Save : LongInt;
begin
If BorderStyle=bsNone then Exit;
Save:=GetWindowLong(Handle,gwl_Style);
If (Save and ws_Caption)<>ws_Caption then Begin
Case BorderStyle of
bsSingle,
bsSizeable : SetWindowLong(Handle,gwl_Style,Save or
ws_Caption or ws_border);
bsDialog : SetWindowLong(Handle,gwl_Style,Save or
ws_Caption or ds_modalframe or ws_dlgframe);
End;
Height:=Height+getSystemMetrics(sm_cyCaption);
Refresh;
End;
end;

Check If a Directory Exists

Delphi Tutorial — Thu, 15 Feb 2007 11:47:30 +0000

How to check if a directory exists?

procedure TForm1.Button1Click(Sender:TObject);
beginÂ
ifÂ DirectoryExists(‘C:\Data’)Â then
beginÂ
ShowMessage(‘Directory already exists’);
end;
end;