I'm trying to use the InitialDir property of TSelectDirectoryDialog:
procedure selectfolder;
begin
SelectDirectoryDialog1.InitialDir := strPath;
If SelectDirectoryDialog1.Execute then begin
Edit1.Text := SelectDirectoryDialog1.FileName;
end;
end;
The first time (with strPath=X) it works fine, the second time I'm using this procedure (with strPath=Y) it doesn't use the new path (Y), but the one I selected previously.
Do I have to call a method, something like SelectDirectoryDialog1."reinitiate" before I set the InitialDir property a second time? Another idea would be to use a different property then InitialDir, but I don't know which one would do the job. Unfortunately the doc page for TSelectDirectoryDialog is currently down, so I don't have a description for the available methods/properties for TSelectDirectoryDialog and the ones I tested to solve my problem.
I got it to work if I create the TSelectDirectoryDialog class instance manually and don't use the one from the Component Palette to create it "on the form". Then I just destroy the instance and create a new one.
procedure TForm1.Button4Click(Sender: TObject);
var SelectDirectoryDialogManual : TSelectDirectoryDialog;
begin
SelectDirectoryDialogManual := TSelectDirectoryDialog.Create(nil);
SelectDirectoryDialogManual.InitialDir := 'C:\Windows';
if SelectDirectoryDialogManual.Execute then ShowMessage(SelectDirectoryDialogManual.FileName);
SelectDirectoryDialogManual.Free;
end;
But how do I do that when I created SelectDirectoryDialog1 using the component Component Palette?
By saving and restoring the value of InitialDir before each invocation of Execute, or doing what #Sertac says in a comment, which works but is less "self-documenting" imo, ymmv.
The code below works fine for me. edInitialDir is a TEdit which saves the most recent directory selected using SelectDirectoryDialog1, which is then used for the next invocation.
procedure TForm1.Button1Click(Sender: TObject);
begin
SelectDirectoryDialog1.InitialDir := edInitialDir.Text;
if SelectDirectoryDialog1.Execute then
Caption := 'executed'
else
Caption := 'not executed';
edInitialDir.Text := SelectDirectoryDialog1.FileName;
end;
Note: All properties of SelectDirectoryDialog1 are the defaults for an instance freshly added from the Component Palette.
Regarding your comment, TSelectDirectoryDialog.Execute calls TWin32WSSelectDirectoryDialog.CreateHandle (see Dialogs.Pas, line 1219). The initial part of this is as follows:
class function TWin32WSSelectDirectoryDialog.CreateHandle(const ACommonDialog: TCommonDialog): THandle;
var
Options : TOpenOptions;
InitialDir : string;
Buffer : PChar;
bi : TBrowseInfo;
iidl : PItemIDList;
biw : TBROWSEINFOW;
Bufferw : PWideChar absolute Buffer;
InitialDirW: widestring;
Title: widestring;
DirName: string;
begin
DirName := '';
InitialDir := TSelectDirectoryDialog(ACommonDialog).FileName;
Options := TSelectDirectoryDialog(ACommonDialog).Options;
if length(InitialDir)=0 then
InitialDir := TSelectDirectoryDialog(ACommonDialog).InitialDir;
if length(InitialDir)>0 then begin
// remove the \ at the end.
if Copy(InitialDir,length(InitialDir),1)=PathDelim then
InitialDir := copy(InitialDir,1, length(InitialDir)-1);
// if it is a rootdirectory, then the InitialDir must have a \ at the end.
if Copy(InitialDir,length(InitialDir),1)=DriveDelim then
InitialDir := InitialDir + PathDelim;
end;
From this you can see that it initially attempts to derive the value of InitialDir from the FileName property and only if that results in an empty string does it attempt to use the stored value of the InitialDir property. This is why the dialog uses the previously-selected directory the next time Execute is invoked, which is exactly what you should be expecting, even if you do not like it. The only way to re-use the initial value of IntialDir from second and subsequent invocations is to restore it before each one.
Related
I am writing which component will run through the array like ['form1.Button1', 'form1.memo1', 'form1'] - like
And put the showms2 handler on it (form1.Button1.onclick: = showms2)
var
comp: array of Tcomponent;
met: Tmethod;
start off
setlength (comp, Lines.Count);
for i: = 0 to Lines.Count-1 do
start off
comp [i]: = (FindComponent (Lines.Names [i]) as TControl);
met: = GetMethodProp (comp [i], 'OnClick');
meth.Code: = form1.MethodAddress ('showms2');
met.Data: = 0;
// When splitting into elements, nothing happens, is there an alternative?
FindComponent() does not work the way you are using it. You need to specify only the name of a component that is directly owned by the component being searched, you can't specify a chain of components, ie Form1.FindComponent('Form1.Button1') won't ever work, but Form1.FindComponent('Button1') will work, if Form1 owns Button1.
Also, if you are going to set both TMethod.Code and TMethod.Data then calling GetMethodProp() is completely redundant and should be removed.
Also, you need to use SetMethodProp() to actually assign the TMethod to the target event.
Try this instead:
var
comp: TComponent;
met: TMethod;
i: Integer;
begin
for i := 0 to Lines.Count-1 do
begin
comp := FindComponent(Lines.Names[i]);
if comp <> nil then
begin
if IsPublishedProp(comp, 'OnClick') then
begin
meth.Code := Form1.MethodAddress('showms2');
meth.Data := Form1;
SetMethodProp(comp, 'OnClick', met);
end;
end;
end;
end;
In Delphi 10.1 Berlin, I'm trying to change a picture on a form by loading a PNG image from a resource.
I've followed this:
Load image from embedded resource
and used a TWICImage to automatically handle different possible image formats.
In this case I specifically want to use a PNG for transparency.
For some reason the function I've created returns nothing.
However, if I call result.savetofile('test.png') within the function the resource is succesfully saved, which verifies that the resource exists in the EXE and has been found.
function LoadImageResource(NativeInstance: NativeUInt; ImageResource: string): TWICImage;
var
Strm: TResourceStream;
WICImage: TWICImage;
begin
Strm := TResourceStream.Create(NativeInstance, ImageResource, RT_RCDATA);
try
Strm.Position := 0;
WICImage := TWICImage.Create;
try
WICImage.LoadFromStream(Strm);
result := WICImage; //these return empty
result.savetofile('test.png'); //this succesfully saves the resource to disk
finally
WICImage.Free;
end;
finally
Strm.Free;
end;
end;
Outside of the function, if I attempt to assign the image by calling for example Image1.picture.assign(LoadFromResource(...)) or Image1.picture.graphic := LoadFromResource(...) nothing gets assigned. And If I then call Image1.savetofile('test.png') I get an access violation error.
What might I be missing?
The problem is that you are destroying the image that you return. It's important to understand that classes are reference types in Delphi. So after the assignment to Result, in your code, you still have only a single instance, but two references to that same single instance.
You need to remove the call to Free.
function LoadImageResource(Module: NativeUInt; const ResName: string): TWICImage;
var
Strm: TResourceStream;
begin
Strm := TResourceStream.Create(Module, ResName, RT_RCDATA);
try
Result := TWICImage.Create;
Result.LoadFromStream(Strm);
finally
Strm.Free;
end;
end;
A little tweak is needed to make the function exception safe:
function LoadImageResource(Module: NativeUInt; const ResName: string): TWICImage;
var
Strm: TResourceStream;
begin
Strm := TResourceStream.Create(Module, ResName, RT_RCDATA);
try
Result := TWICImage.Create;
try
Result.LoadFromStream(Strm);
except
Result.Free;
raise;
end;
finally
Strm.Free;
end;
end;
When you call the function it behaves like a constructor. It either succeeds and returns a new instance, handing over ownership to the caller. Or it raises an exception. Accordingly I would name the function CreateImageFromResource.
Basically, I have 8 panels and I want to assign to all of them a picture by using a loop, to do that I used a TComponent variable and an image that I create during runtime. But I am unable to find a way to assign that image a parent using this string ('pnlDisplay' + inttostr(i)).
So my code looks something like this:
var
imgPanel : TImage;
cPanel : TComponent;
begin
for i := 1 to 8 do
begin
cPanel := FindComponent('pnlDisplay' + inttostr(i));
imgPanel := TImage.Create(cPanel);
imgPanel.Parent := cPanel; //Here is my problem
imgPanel.Picture.LoadFromFile('Pic' + inttostr(i) + '.jpg');
imgPanel.Visible := True;
end;
end
Any help or even another way to achieve this would be helpful.
FindComponent() returns a TComponent, whereas the Parent property expects a TWinControl instead. Assuming FindComponent() is returning the correct component, just type-cast it:
imgPanel.Parent := TWinControl(cPanel);
I use a timage in a form which load a background image.
The problem is when i choose another picture in run time and change it by
Img_Bk.Picture.LoadFromFile( SaveFileName );
It doesnt work (Picture did n't change ). I mean it shows previous picture and doesn't show the new image during run time. Id like to change application background image during run time in my company by users which main form is a mdi form .
I use delphi 7 .
try
Img_Bk.Picture := nil ;
if FileSize > 100 then
begin
Img_Bk.Picture.LoadFromFile( SaveFileName );
end;
Img_Bk.Stretch := True ;
except
end;
LoadFromFile is known to work. So there must be a more prosaic explanation.
The first possible explanation is that FileSize is not greater than 100 and the if condition evaluates false.
Another possible explanation is that the image in the file that you specify is not the one you are expecting.
Otherwise, your code has a swallow all exception handler. And so when the call to LoadFromFile fails and raises an exception, your code ignores that and carries on as if nothing un-toward had happened. Remove the try/except, and deal with the error that will be revealed.
The real lesson for you to learn is never to write such an exception handler again.
This program should prove to you that LoadFromFile is just fine:
program ImageDemo;
uses
Types, Math, IOUtils, SHFolder, Forms, Controls, StdCtrls, ExtCtrls, jpeg;
var
Form: TForm;
Image: TImage;
Timer: TTimer;
ImageIndex: Integer = -1;
MyPictures: string;
Images: TStringDynArray;
type
THelper = class
class procedure Timer(Sender: TObject);
end;
class procedure THelper.Timer(Sender: TObject);
begin
inc(ImageIndex);
if ImageIndex>high(Images) then
ImageIndex := 0;
if ImageIndex>high(Images) then
exit;
Image.Picture.LoadFromFile(Images[ImageIndex]);
end;
function GetMyPictures: string;
var
Str: array[0..260] of Char;
begin
if SHGetFolderPath(0, CSIDL_MYPICTURES, 0, 0, Str) = S_OK then
Result := Str;
end;
procedure BuildForm;
begin
Form.ClientWidth := 700;
Form.ClientHeight := 500;
Image := TImage.Create(Form);
Image.Parent := Form;
Image.Align := alClient;
Image.Stretch := True;
Timer := TTimer.Create(Form);
Timer.OnTimer := THelper.Timer;
Timer.Interval := 100;
end;
begin
MyPictures := GetMyPictures;
Images := TDirectory.GetFiles(MyPictures, '*.jpg', TSearchOption.soAllDirectories);
Application.MainFormOnTaskbar := True;
Application.CreateForm(TForm, Form);
BuildForm;
Application.Run;
end.
I had the same problem today. After the call of LoadFromFile() the image does not change. I have tried Refresh, Repaint, Invalidate and Update -> nothing helped. Then I found that resizing the from immediately updated the image.
Finally I found that setting property Visible to false and back to true updates the image, too.
FormMain.Image1.Visible := false;
FormMain.Image1.Picture.LoadFromFile(newImageFileName);
FormMain.Image1.Visible := true;
Perhaps not the best but it works for me.
Some background (kind of a continuation of TLabel and TGroupbox Captions Flicker on Resize):
So, I have an application that loads different plugins and creates a
new tab on a TPageControl for each one.
Each DLL has a TForm associated with it.
The forms are created with their parent hWnd as the new TTabSheet.
Since the TTabSheets aren't a parent of the form as far as VCL is
concerned (didn't want to use dynamic RTL, and plugins made in
other languages) I have to handle resizes manually.
I just seem to be running into a lot of new issues (but great learning experiences) for this "plugin" type of application.
So, my current struggle is trying to have a plugin that doesn't get inserted into a TTabSheet but will be resized and aligned directly on the form.
Since this would be easier to explain with a picture:
Now I could manually do the alignment and the resize, but I'd much rather have the VCL alignment procedures (alClient, alTop, etc) do it for me. That way I would just have to set the plugins alignment on its form without thinking.
After looking through the VCL source I began to step through the align code and how it's called. Basically when a TControl gets a WM_RESIZE it will:
Call Realign() which calls AlignControl()
AlignControl() will get the client rect and call AlignControls()
AlignControls() will call DoAlign() for each TAlignment type in this order: alTop, alBottom, alLeft, alRight, alClient, alCustom, alNone
DoAlign() will loop through FControls and FWinControls (which are TLists) and will align them appropriately
So my thought process is that if I create a new TWinControl, set it's handle to the plugins form (window) handle, and insert it into the FControls list with the proper align it should do my work for me.
Of course I'm here, so it failed miserably. I even get an AV when exiting the application about an invalid window handle. My guess is that the TWinControl I created is trying to free the handle of the plugins form (window) which doesn't exist any more.
What I've tried:
procedure AddHandleToControlList(AHandle: DWORD; Align: TAlign);
var
NewWinControl : TWinControl;
begin
NewWinControl := TWinControl.Create(frmMain);
NewWinControl.WindowHandle := AHandle;
NewWinControl.Align := Align;
NewWinControl.Width := frmMain.ClientWidth;
NewWinControl.Height := 30;
NewWinControl.Parent := frmMain;
end;
procedure AddHandleToControlList(AHandle: DWORD; Align: TAlign);
var
NewWinControl : TWinControl;
begin
NewWinControl := TWinControl.Create(frmMain);
NewWinControl.WindowHandle := AHandle;
NewWinControl.Align := Align;
NewWinControl.Width := frmMain.ClientWidth;
NewWinControl.Height := 30;
TWinControl(frmMain).Insert(NewWinControl);
end;
Soooo, thoughts?
EDIT 1:
Ok, so this correctly adds the control to the list and conforms the the TAlign set (why is it that I spend 8 hours trying to figure something out, I post here, and then the answer just appears...oh well someone might find this question and my ramblings useful):
procedure AddHandleToControlList(AHandle: DWORD; AName: PChar; ATop, ALeft, AWidth, AHeight: Integer; AAlign: TAlign);
var
NewWinControl : TWinControl;
begin
NewWinControl := TWinControl.Create(frmMain);
With NewWinControl Do
begin
Name := AName;
Top := ATop;
Left := ALeft;
Width := AWidth;
Height := AHeight;
Align := AAlign;
WindowHandle := AHandle;
Visible := True;
end;
TWinControl(frmMain).InsertControl(NewWinControl);
end;
The issue now is that when the application closes, I get the invalid error AV...I shall continue!!
EDIT 2:
Ok, so it is TWinControl.DestroyWindowHandle that raises the AV because the window handle doesn't exist any more. I'm trying to think of a clean solution.
Derive a new class from TWinControl and override its virtual DestroyWindowHandle() method to not free the HWND you provide. The default implementation of TWinControl.DestroyWindowHandle() calls the Win32 API DestroyWnd() function.