neoturk: ...Change a hint's font ?...
{
When the application displays a Help Hint,
it creates an instance of HintWindowClass to represent
the window used for displaying the hint.
Applications can customize this window by creating a
descendant of THintWindow and assigning it to the
HintWindowClass variable at application startup.
}
type
TMyHintWindow = class(THintWindow)
constructor Create(AOwner: TComponent); override;
end;
implementation
{....}
constructor TMyHintWindow.Create(AOwner: TComponent);
begin
inherited Create(AOwner);
with Canvas.Font do
begin
Name := 'Arial';
Size := Size + 5;
Style := [fsBold];
end;
end;
procedure TForm2.FormCreate(Sender: TObject);
begin
HintWindowClass := TMyHintWindow;
Application.ShowHint := False;
Application.ShowHint := True;
end;
Delphi - .....................................
neoturk: ...Use the tools menu in the ide ?...
The menu "Tools" is a free configurable part of the Delphi-IDE.
You can there insert tools, you often use while coding.
I (for example) have the MSDN and another Editor in there.
First choose Tools / Configure Tools. Then click Add, to add another item.
Title is the caption beeing showed, when you open the tools menu.
A & makes the next letter to the QuickSelect letter.
Program is the program, you want to launch.
Use here (for example) "C:Program FilesTextPadTextPad.exe".
If you have spaces in you path or filename, quote the hole string.
Working dir is the directory, the program will be launched.
It's normally the same as the program directory.
Parameters are beeing given to the program, you run, or (in case of macros) are beeing run,
when you select the item. Click on parameters, to show a list of macros for use with it.
With a second editor, the macros $SAVEALL and $NAME will be usefull.
To make the menu more structured, you can use a horizontal rule.
You create one, by entering - in the Title field.
Cause of a bug in the Delphi IDE, you cannot create a second rule as easy.
You'll have to enter another caption first and then rename it.
{***************************************************************************}
Das Tools Menu ist ein frei konfigurierbarer Teil der Delphi-IDE.
Man kann darin Programme, die man oft zur Entwicklung von Delphi-Programmen braucht konfigurieren,
um sie bei Bedarf schneller zu öffnen.
Ich habe dort drin z.B. die MSDN und ein alternativer Editor für Delphi-Sources, sowie einige andere Tools.
Zuerst wählt man Tools / Configure Tools. In dem dann erscheinenden Menu kann man per
Add neue Einträge hinzufügen.
Unter Title gibt man den Namen an, der erscheinen soll. '&' unterstreicht den nächsten Buchstaben
(QuickSelect).
Unter Programm gibt man das Programm an, welches man starten möchte.
Z.B. C:ProgrammeTextPadTextPad.exe. Wenn der Pfad Leerzeichen enthält,
muss man entweder alles ins 8.3-Format konvertieren, oder den Pfad mit "" schreiben.
Unter Working Dir sollte man den Pfad angeben, in dem auch das Programm ist.
Unter Parameters kann man Makros sowie auch Parameter für das Programm hinzufügen.
Mit einem Klick auf Macros öffnet sich eine Liste mit den vorhandenen Makros mit kurzer Beschreibung.
Für einen zweiten Editor währe z.B. $SAVEALL, sowie $NAME sehr nützlich.
Um das ganze Menu besser Strukturieren zu können, können Horizontale Linien angelegt werden.
Dies macht man mit einem neuen Item, dass unter Title einen - (Bindestrich) drin hat.
Leider hat es in Delphi einen Bug, der verhindert, dass man zwei mal das "selbe" Item anlegt.
Um noch eine zweite Linie zu erstellen, muss man zuerst einen anderen Namen nehmen (z.B. Temp)
und dann unter Edit das auf - ändern.
Delphi - .....................................
neoturk: ...Use the tools menu in the ide ?...
The menu "Tools" is a free configurable part of the Delphi-IDE.
You can there insert tools, you often use while coding.
I (for example) have the MSDN and another Editor in there.
First choose Tools / Configure Tools. Then click Add, to add another item.
Title is the caption beeing showed, when you open the tools menu.
A & makes the next letter to the QuickSelect letter.
Program is the program, you want to launch.
Use here (for example) "C:Program FilesTextPadTextPad.exe".
If you have spaces in you path or filename, quote the hole string.
Working dir is the directory, the program will be launched.
It's normally the same as the program directory.
Parameters are beeing given to the program, you run, or (in case of macros) are beeing run,
when you select the item. Click on parameters, to show a list of macros for use with it.
With a second editor, the macros $SAVEALL and $NAME will be usefull.
To make the menu more structured, you can use a horizontal rule.
You create one, by entering - in the Title field.
Cause of a bug in the Delphi IDE, you cannot create a second rule as easy.
You'll have to enter another caption first and then rename it.
{***************************************************************************}
Das Tools Menu ist ein frei konfigurierbarer Teil der Delphi-IDE.
Man kann darin Programme, die man oft zur Entwicklung von Delphi-Programmen braucht konfigurieren,
um sie bei Bedarf schneller zu öffnen.
Ich habe dort drin z.B. die MSDN und ein alternativer Editor für Delphi-Sources, sowie einige andere Tools.
Zuerst wählt man Tools / Configure Tools. In dem dann erscheinenden Menu kann man per
Add neue Einträge hinzufügen.
Unter Title gibt man den Namen an, der erscheinen soll. '&' unterstreicht den nächsten Buchstaben
(QuickSelect).
Unter Programm gibt man das Programm an, welches man starten möchte.
Z.B. C:ProgrammeTextPadTextPad.exe. Wenn der Pfad Leerzeichen enthält,
muss man entweder alles ins 8.3-Format konvertieren, oder den Pfad mit "" schreiben.
Unter Working Dir sollte man den Pfad angeben, in dem auch das Programm ist.
Unter Parameters kann man Makros sowie auch Parameter für das Programm hinzufügen.
Mit einem Klick auf Macros öffnet sich eine Liste mit den vorhandenen Makros mit kurzer Beschreibung.
Für einen zweiten Editor währe z.B. $SAVEALL, sowie $NAME sehr nützlich.
Um das ganze Menu besser Strukturieren zu können, können Horizontale Linien angelegt werden.
Dies macht man mit einem neuen Item, dass unter Title einen - (Bindestrich) drin hat.
Leider hat es in Delphi einen Bug, der verhindert, dass man zwei mal das "selbe" Item anlegt.
Um noch eine zweite Linie zu erstellen, muss man zuerst einen anderen Namen nehmen (z.B. Temp)
und dann unter Edit das auf - ändern.
Delphi - .....................................
neoturk: ...Create a sizable and none border style form ?...
{
With this code you can create none border style (BorderStyle = bsNone)
but sizeable windows (forms)
First you must set BorderStyle := bsNone of your Form in Object Browser.
There is your small but forced code;
}
type
TForm1 = class(TForm)
private
{ Private declarations }
public
{ Public declarations }
procedure CreateParams(var Params: TCreateParams); override;
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
procedure TForm1.CreateParams(var Params: TCreateParams);
begin
inherited CreateParams(Params);
Params.Style := (Params.Style or WS_THICKFRAME);
end;
Delphi - .....................................
neoturk: ...Create a sizable and none border style form ?...
{
With this code you can create none border style (BorderStyle = bsNone)
but sizeable windows (forms)
First you must set BorderStyle := bsNone of your Form in Object Browser.
There is your small but forced code;
}
type
TForm1 = class(TForm)
private
{ Private declarations }
public
{ Public declarations }
procedure CreateParams(var Params: TCreateParams); override;
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
procedure TForm1.CreateParams(var Params: TCreateParams);
begin
inherited CreateParams(Params);
Params.Style := (Params.Style or WS_THICKFRAME);
end;
Delphi - .....................................
neoturk: ...Correct a bidi bug in delphi ?...
{
When you set the BiDiMode in you form to bdRightToLeft, you do only HALF mirroring.
Since Win98 (Hebrew/Arabic version) mirror it's envirement completly
(the Minimize, Close, Maxmize buttons are on the Left, and the Icon is on the right).
How can we do it in delphi ?
}
{...}
const
WS_EX_LAYOUTRTL = $00400000;
WS_EX_LAYOUT_RTL = WS_EX_LAYOUTRTL;
{...}
TForm1 = class(TForm)
procedure FormCreate(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
procedure CreateParams(var Params : TCreateParams); override;
end;
{...}
implementation
procedure TForm1.CreateParams(var Params : TCreateParams);
begin
inherited CreateParams(Params);
Params.ExStyle := WS_EX_LEFT or WS_EX_RTLREADING or WS_EX_LEFTSCROLLBAR or WS_EX_LAYOUT_RTL;
{WS_EX_LEFT to set the text caption to the right,
use WS_EX_RIGHT to set the caption to the left}
end;
procedure TForm1.FormCreate(Sender: TObject);
begin
BiDiMode := bdLeftToRight; //A must !!!
end;
{The result is Right to Left (including the buttons, the icon and the system menu) }
Delphi - .....................................
neoturk: ...Correct a bidi bug in delphi ?...
{
When you set the BiDiMode in you form to bdRightToLeft, you do only HALF mirroring.
Since Win98 (Hebrew/Arabic version) mirror it's envirement completly
(the Minimize, Close, Maxmize buttons are on the Left, and the Icon is on the right).
How can we do it in delphi ?
}
{...}
const
WS_EX_LAYOUTRTL = $00400000;
WS_EX_LAYOUT_RTL = WS_EX_LAYOUTRTL;
{...}
TForm1 = class(TForm)
procedure FormCreate(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
procedure CreateParams(var Params : TCreateParams); override;
end;
{...}
implementation
procedure TForm1.CreateParams(var Params : TCreateParams);
begin
inherited CreateParams(Params);
Params.ExStyle := WS_EX_LEFT or WS_EX_RTLREADING or WS_EX_LEFTSCROLLBAR or WS_EX_LAYOUT_RTL;
{WS_EX_LEFT to set the text caption to the right,
use WS_EX_RIGHT to set the caption to the left}
end;
procedure TForm1.FormCreate(Sender: TObject);
begin
BiDiMode := bdLeftToRight; //A must !!!
end;
{The result is Right to Left (including the buttons, the icon and the system menu) }
Delphi - .....................................
neoturk: ...Create a transparent tform ?...
private
{ Private declarations }
FullRgn, ClientRgn, CtlRgn: THandle;
procedure MakeTransparent;
procedure UndoTransparent;
end;
{...}
implementation
{...}
procedure TForm1.MakeTransparent;
var
AControl: TControl;
A, Margin, X, Y, CtlX, CtlY: Integer;
begin
Margin := (Width - ClientWidth) div 2;
FullRgn := CreateRectRgn(0, 0, Width, Height);
X := Margin;
Y := Height - ClientHeight - Margin;
ClientRgn := CreateRectRgn(X, Y, X + ClientWidth, Y + ClientHeight);
CombineRgn(FullRgn, FullRgn, ClientRgn, RGN_DIFF);
for A := 0 to ControlCount - 1 do
begin
AControl := Controls[A];
if (AControl is TWinControl) or (AControl is TGraphicControl) then with AControl do
begin
if Visible then
begin
CtlX := X + Left;
CtlY := Y + Top;
CtlRgn := CreateRectRgn(CtlX, CtlY, CtlX + Width, CtlY + Height);
CombineRgn(FullRgn, FullRgn, CtlRgn, RGN_OR);
end;
end;
end;
SetWindowRgn(Handle, FullRgn, True);
end;
procedure TForm1.UndoTransparent;
begin
FullRgn := CreateRectRgn(0, 0, Width, Height);
CombineRgn(FullRgn, FullRgn, FullRgn, RGN_COPY);
SetWindowRgn(Handle, FullRgn, True);
end;
// Test it:
procedure TForm1.Button1Click(Sender: TObject);
begin
MakeTransparent
end;
procedure TForm1.Button1Click(Sender: TObject);
begin
UndoTransparent
end;
Delphi - .....................................
neoturk: ...Create a transparent tform ?...
private
{ Private declarations }
FullRgn, ClientRgn, CtlRgn: THandle;
procedure MakeTransparent;
procedure UndoTransparent;
end;
{...}
implementation
{...}
procedure TForm1.MakeTransparent;
var
AControl: TControl;
A, Margin, X, Y, CtlX, CtlY: Integer;
begin
Margin := (Width - ClientWidth) div 2;
FullRgn := CreateRectRgn(0, 0, Width, Height);
X := Margin;
Y := Height - ClientHeight - Margin;
ClientRgn := CreateRectRgn(X, Y, X + ClientWidth, Y + ClientHeight);
CombineRgn(FullRgn, FullRgn, ClientRgn, RGN_DIFF);
for A := 0 to ControlCount - 1 do
begin
AControl := Controls[A];
if (AControl is TWinControl) or (AControl is TGraphicControl) then with AControl do
begin
if Visible then
begin
CtlX := X + Left;
CtlY := Y + Top;
CtlRgn := CreateRectRgn(CtlX, CtlY, CtlX + Width, CtlY + Height);
CombineRgn(FullRgn, FullRgn, CtlRgn, RGN_OR);
end;
end;
end;
SetWindowRgn(Handle, FullRgn, True);
end;
procedure TForm1.UndoTransparent;
begin
FullRgn := CreateRectRgn(0, 0, Width, Height);
CombineRgn(FullRgn, FullRgn, FullRgn, RGN_COPY);
SetWindowRgn(Handle, FullRgn, True);
end;
// Test it:
procedure TForm1.Button1Click(Sender: TObject);
begin
MakeTransparent
end;
procedure TForm1.Button1Click(Sender: TObject);
begin
UndoTransparent
end;
Delphi - .....................................
neoturk: ...Check if a tmainmenu is dropped down or not ?...
type
TForm1 = class(TForm)
// ...
private
IsMenuOpen: Boolean;
procedure WMMENUSELECT(var message: TWMMENUSELECT); message WM_MENUSELECT;
end;
implementation
procedure TForm1.WMMENUSELECT(var message: TWMMENUSELECT);
begin
inherited;
IsMenuOpen := not ((message.MenuFlag and $FFFF = 0) and (message.Menu = 0));
end;
Delphi - .....................................
neoturk: ...Check if a tmainmenu is dropped down or not ?...
type
TForm1 = class(TForm)
// ...
private
IsMenuOpen: Boolean;
procedure WMMENUSELECT(var message: TWMMENUSELECT); message WM_MENUSELECT;
end;
implementation
procedure TForm1.WMMENUSELECT(var message: TWMMENUSELECT);
begin
inherited;
IsMenuOpen := not ((message.MenuFlag and $FFFF = 0) and (message.Menu = 0));
end;
Delphi - .....................................
neoturk: ...Check if a popup menu is open ?...
{
Using the WM_MENUSELECT message of the form won’t work to check if
the popup is open. Simply because the parent of the popup is not the
form (check the popup method of TPopupMenu). A workaround is to use
the api call yourself :
}
type
TForm1 = class(TForm)
{...}
procedure FormMouseDown(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
private
IsMenuOpen: Boolean;
procedure WMMENUSELECT(var msg: TWMMENUSELECT); message WM_MENUSELECT;
end;
{...}
implementation
{...}
procedure TForm1.WMMENUSELECT(var msg: TWMMENUSELECT);
begin
inherited;
IsMenuOpen := not ((msg.MenuFlag and $FFFF > 0) and
(msg.Menu = 0));
end;
procedure TForm1.FormMouseDown(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
begin
if Button = mbRight then
with ClientToScreen(Point(X, Y)) do
TrackPopupMenuEx(PopupMenu1.Handle, TPM_LEFTALIGN, X, Y,
Self.Handle, nil);
end;
Delphi - .....................................
neoturk: ...Check if a popup menu is open ?...
{
Using the WM_MENUSELECT message of the form won’t work to check if
the popup is open. Simply because the parent of the popup is not the
form (check the popup method of TPopupMenu). A workaround is to use
the api call yourself :
}
type
TForm1 = class(TForm)
{...}
procedure FormMouseDown(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
private
IsMenuOpen: Boolean;
procedure WMMENUSELECT(var msg: TWMMENUSELECT); message WM_MENUSELECT;
end;
{...}
implementation
{...}
procedure TForm1.WMMENUSELECT(var msg: TWMMENUSELECT);
begin
inherited;
IsMenuOpen := not ((msg.MenuFlag and $FFFF > 0) and
(msg.Menu = 0));
end;
procedure TForm1.FormMouseDown(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
begin
if Button = mbRight then
with ClientToScreen(Point(X, Y)) do
TrackPopupMenuEx(PopupMenu1.Handle, TPM_LEFTALIGN, X, Y,
Self.Handle, nil);
end;
Delphi - .....................................
neoturk: ...Read data from another mdichild form ?...
type
TMDIChildForm = class(TForm)
Edit1: TEdit;
private
{ Private declarations }
procedure ReadDataFromOtherMDIChildForm;
end;
var
MDIChildForm: TMDIChildForm;
implementation
{$R *.DFM}
uses
MainForm;
// Property FormStyle of this form is fsMDIForm
procedure TMDIChildForm.ReadDataFromOtherMDIChildForm;
var
i: Integer;
DataFromOtherForm: string;
begin
// Suppose you have created three different MDIChild forms of the same type,
// each with the following caption: "aaa", "bbb", "ccc".
// You are currently on form with caption "aaa" and want to read data
// contained on form with caption "ccc".
// You can find here the code, you have to use the "as" clause and
// properties MDIChildCount and MDIChildren:
// First you have to find where the form "ccc" is in memory;
for i := 0 to MDIForm.MDIChildCount - 1 do
begin
if (Pos('ccc', MDIForm.MDIChildren[i].Caption) 0) then
Break;
end;
// Check to see if the form is the last on MDIChildren array and
// correct I variable
if (i = MDIChildCount) then Dec(i);
// I variable contains the index of the form with caption 'ccc'
if (Pos('ccc', MDIForm.MDIChildren[i].Caption) 0) then
begin
// If the form with caption 'ccc' exists then you access data and show it
// The following line of code is very interesting, look at the "as" clause,
// if you have different types of MDIChild forms, you simply change
// the type of form after the "as" clause
// The data you want is contained on Edit1.Text
with (MDIForm.MDIChildren[I] as TMDIChildForm).Edit1 do
DataFromOtherForm := Text;
ShowMessage(DataFromOtherForm);
end;
end;
Delphi - .....................................
neoturk: ...Read data from another mdichild form ?...
type
TMDIChildForm = class(TForm)
Edit1: TEdit;
private
{ Private declarations }
procedure ReadDataFromOtherMDIChildForm;
end;
var
MDIChildForm: TMDIChildForm;
implementation
{$R *.DFM}
uses
MainForm;
// Property FormStyle of this form is fsMDIForm
procedure TMDIChildForm.ReadDataFromOtherMDIChildForm;
var
i: Integer;
DataFromOtherForm: string;
begin
// Suppose you have created three different MDIChild forms of the same type,
// each with the following caption: "aaa", "bbb", "ccc".
// You are currently on form with caption "aaa" and want to read data
// contained on form with caption "ccc".
// You can find here the code, you have to use the "as" clause and
// properties MDIChildCount and MDIChildren:
// First you have to find where the form "ccc" is in memory;
for i := 0 to MDIForm.MDIChildCount - 1 do
begin
if (Pos('ccc', MDIForm.MDIChildren[i].Caption) 0) then
Break;
end;
// Check to see if the form is the last on MDIChildren array and
// correct I variable
if (i = MDIChildCount) then Dec(i);
// I variable contains the index of the form with caption 'ccc'
if (Pos('ccc', MDIForm.MDIChildren[i].Caption) 0) then
begin
// If the form with caption 'ccc' exists then you access data and show it
// The following line of code is very interesting, look at the "as" clause,
// if you have different types of MDIChild forms, you simply change
// the type of form after the "as" clause
// The data you want is contained on Edit1.Text
with (MDIForm.MDIChildren[I] as TMDIChildForm).Edit1 do
DataFromOtherForm := Text;
ShowMessage(DataFromOtherForm);
end;
end;
Delphi - .....................................
neoturk: ...Check if a control is partially covered by another window ?...
{
You would have to iterate over all windows above yours in Z-order and
check for each window you find if it has the WS_EX_TOPMOST exstyle set
and is visible.
If it has, you have to get its window rectangle (GetWindowRect) and test
if that overlaps your window.
Example:
}
procedure TForm1.Button1Click(Sender: TObject);
var
wnd: HWND;
function IsTopMost(wnd: HWND): Boolean;
begin
Result := (GetWindowLong(wnd, GWL_EXSTYLE) and WS_EX_TOPMOST) <> 0;
end;
procedure logWindowInfo(wnd: HWND);
const
visString: array[Boolean] of string = ('not ', '');
var
buffer: array[0..256] of Char;
r: TRect;
begin
if wnd = 0 then Exit;
GetClassName(wnd, buffer, SizeOf(buffer));
with Memo1.Lines do
begin
Add(Format(' Window of class %s ', [buffer]));
GetWindowRect(wnd, r);
Add(Format(' at (%d,%d):(%d,%d)', [r.Left, r.Top, r.Right, r.Bottom]));
Add(Format(' Window is %svisible', [visString[IsWindowVisible(wnd)]]));
Add(Format(' Window is %stopmost', [visString[IsTopmost(wnd)]]));
end;
end;
begin
Memo1.Clear;
wnd := Handle;
repeat
wnd := GetNextWindow(wnd, GW_HWNDPREV);
LogWindowInfo(wnd);
until wnd = 0;
Memo1.Lines.Add('End log.');
end;
Delphi - .....................................
neoturk: ...Check if a control is partially covered by another window ?...
{
You would have to iterate over all windows above yours in Z-order and
check for each window you find if it has the WS_EX_TOPMOST exstyle set
and is visible.
If it has, you have to get its window rectangle (GetWindowRect) and test
if that overlaps your window.
Example:
}
procedure TForm1.Button1Click(Sender: TObject);
var
wnd: HWND;
function IsTopMost(wnd: HWND): Boolean;
begin
Result := (GetWindowLong(wnd, GWL_EXSTYLE) and WS_EX_TOPMOST) <> 0;
end;
procedure logWindowInfo(wnd: HWND);
const
visString: array[Boolean] of string = ('not ', '');
var
buffer: array[0..256] of Char;
r: TRect;
begin
if wnd = 0 then Exit;
GetClassName(wnd, buffer, SizeOf(buffer));
with Memo1.Lines do
begin
Add(Format(' Window of class %s ', [buffer]));
GetWindowRect(wnd, r);
Add(Format(' at (%d,%d):(%d,%d)', [r.Left, r.Top, r.Right, r.Bottom]));
Add(Format(' Window is %svisible', [visString[IsWindowVisible(wnd)]]));
Add(Format(' Window is %stopmost', [visString[IsTopmost(wnd)]]));
end;
end;
begin
Memo1.Clear;
wnd := Handle;
repeat
wnd := GetNextWindow(wnd, GW_HWNDPREV);
LogWindowInfo(wnd);
until wnd = 0;
Memo1.Lines.Add('End log.');
end;
Delphi - .....................................
neoturk: ...Prevent a control from redrawing [refreshing] ?...
{
Question:
Is there a way to stop a component from refreshing until I've completed some
processing?
Answer:
Yes. Most controls can be blocked from redrawing by sending a WM_SETREDRAW
message with wParam = 0 to them. Once you have finished the changes you send
another WM_SETREDRAW with wparam = 1. For a grid this would look like this:
}
{
Frage:
Gibt es eine Möglichkeit, dass sich eine Komponente solange nicht neu zeichnet,
bis ich mit einer Verarbeitungsroutine fertig bin?
Antwort:
Ja. Die meisten Controls können "eingefroren" werden, indem man ihnen ein
WM_SETREDRAW Nachricht mit wParam = 0 schickt.
Danach kann man WM_SETREDRAW mit wparam = 1 schicken, um das Updaten wieder zulassen.
Für ein Grid sieht es z.B so aus:
}
procedure LockControl(c: TWinControl; bLock: Boolean);
begin
if (c = nil) or (c.Handle = 0) then Exit;
if bLock then
SendMessage(c.Handle, WM_SETREDRAW, 0, 0)
else
begin
SendMessage(c.Handle, WM_SETREDRAW, 1, 0);
RedrawWindow(c.Handle, nil, 0,
RDW_ERASE or RDW_FRAME or RDW_INVALIDATE or RDW_ALLCHILDREN);
end;
end;
procedure TForm1.Button1Click(Sender: TObject);
begin
LockControl(DBGrid1, True);
try
// do convoluted things to the grid
finally
LockControl(DBGrid1, False);
end;
end;
{
A number of controls have a build-in way to do that, the BeginUpdate and
EndUpdate methods. You often find these not on the control itself but on
some object property that manages the controls data, e.g. for a TMemo you use
Lines.BeginUpdate and Lines.EndUpdate. The EndUpdate automatically forces a
redraw of the control.
}
{
Viele Controls besitzen schon die Methoden BeginUpdate und EndUpdate.
Meistens findest man diese Methoden nicht direkt beim Control aber bei
einer Objekt Eigenschaft, welche diese Methoden aufweist.
Bei einem TMemo kann man z.B Lines.BeginUpdate und Lines.EndUpdate aufrufen.
Mit BeginUpdate kann man verhindern, daß die Bildschirmanzeige aktualisiert wird,
wenn Einträge angehängt, gelöscht und eingefügt werden. EndUpdate veranlasst
das Control neu zu zeichnen.
}
Delphi - .....................................
neoturk: ...Prevent a control from redrawing [refreshing] ?...
{
Question:
Is there a way to stop a component from refreshing until I've completed some
processing?
Answer:
Yes. Most controls can be blocked from redrawing by sending a WM_SETREDRAW
message with wParam = 0 to them. Once you have finished the changes you send
another WM_SETREDRAW with wparam = 1. For a grid this would look like this:
}
{
Frage:
Gibt es eine Möglichkeit, dass sich eine Komponente solange nicht neu zeichnet,
bis ich mit einer Verarbeitungsroutine fertig bin?
Antwort:
Ja. Die meisten Controls können "eingefroren" werden, indem man ihnen ein
WM_SETREDRAW Nachricht mit wParam = 0 schickt.
Danach kann man WM_SETREDRAW mit wparam = 1 schicken, um das Updaten wieder zulassen.
Für ein Grid sieht es z.B so aus:
}
procedure LockControl(c: TWinControl; bLock: Boolean);
begin
if (c = nil) or (c.Handle = 0) then Exit;
if bLock then
SendMessage(c.Handle, WM_SETREDRAW, 0, 0)
else
begin
SendMessage(c.Handle, WM_SETREDRAW, 1, 0);
RedrawWindow(c.Handle, nil, 0,
RDW_ERASE or RDW_FRAME or RDW_INVALIDATE or RDW_ALLCHILDREN);
end;
end;
procedure TForm1.Button1Click(Sender: TObject);
begin
LockControl(DBGrid1, True);
try
// do convoluted things to the grid
finally
LockControl(DBGrid1, False);
end;
end;
{
A number of controls have a build-in way to do that, the BeginUpdate and
EndUpdate methods. You often find these not on the control itself but on
some object property that manages the controls data, e.g. for a TMemo you use
Lines.BeginUpdate and Lines.EndUpdate. The EndUpdate automatically forces a
redraw of the control.
}
{
Viele Controls besitzen schon die Methoden BeginUpdate und EndUpdate.
Meistens findest man diese Methoden nicht direkt beim Control aber bei
einer Objekt Eigenschaft, welche diese Methoden aufweist.
Bei einem TMemo kann man z.B Lines.BeginUpdate und Lines.EndUpdate aufrufen.
Mit BeginUpdate kann man verhindern, daß die Bildschirmanzeige aktualisiert wird,
wenn Einträge angehängt, gelöscht und eingefügt werden. EndUpdate veranlasst
das Control neu zu zeichnen.
}
Delphi - .....................................
