[CLOSED] WebView4Delphi question
lazarus / 38-Networking and Web Programming

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egsuh · 2025-10-31 11:18

Hello,

I'd like to make a form simply shows the HTML page made from my
program using WebView4Delphi.
The form is created on fly as follows.


Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
TForm1.Button2Click(Sender: TObject);var   ts: string;begin   ts :=
aqfb5.printQnnr('100000042', -100);    with TfrBrowser.Create(nil, ts)
do  begin        Show;       
wvbrowser1.navigatetostring(UTF8Decode(ts));  // but this does not
work.    end;end;         
The content of ts is displayed well on normal webbrowsers. What I want
to do is to show this content in a pop-up window, e.g. Tfrbrowser
created. 

But in the above example, I cannot execute
wvbrowser1.navigatetostring(UTF8Decode(ts)); . I do not know why. 
Possibly becasue of asynchronous process, etc.


Content of fbrowser.pas is as following. 

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i unit
fbrowser; {$mode delphi} interface uses   Classes, SysUtils, Forms,
Controls, Graphics, Dialogs,   uWVBrowser, uWVWindowParent, uWVLoader,
uWVBrowserBase, uWVTypes, uWVEvents,   Messages; type    { TfrBrowser
}    TfrBrowser = class(TForm)      WVBrowser1: TWVBrowser;     
WVWindowParent1: TWVWindowParent;      procedure FormClose(Sender:
TObject; var CloseAction: TCloseAction);      procedure
FormResize(Sender: TObject);      procedure FormShow(Sender:
TObject);      procedure WVBrowser1AfterCreated(Sender: TObject); 
 private      FTextContent: string;      procedure
setBrowserContent(AValue: string);      procedure Initialize;  
 public      property HTMLText : string write setBrowserContent;     
constructor Create(AnOwner:TComponent; TextContent: string);  
 protected      procedure WMMove(var aMessage: TWMMove);  message
WM_MOVE;      procedure WMMoving(var aMessage: TMessage); message
WM_MOVING;    end; var   frBrowser: TfrBrowser; implementation {$R
*.lfm} procedure TfrBrowser.WVBrowser1AfterCreated(Sender:
TObject);begin    WVWindowParent1.UpdateSize;    Caption := 'View
responses';end; procedure TfrBrowser.setBrowserContent(AValue:
string);begin 
 WVBrowser1.NavigateToString(UTF8Decode(AValue));end; procedure
TfrBrowser.Initialize;begin  if
GlobalWebView2Loader.InitializationError then   
showmessage(UTF8Encode(GlobalWebView2Loader.ErrorMessage))   else   
if GlobalWebView2Loader.Initialized then begin     
 WVBrowser1.CreateBrowser(WVWindowParent1.Handle);    end    else
begin      showmessage('initialization failed');      exit;   
end;end; constructor TfrBrowser.Create(AnOwner: TComponent;
TextContent: string);begin   inherited Create(AnOwner);  
 FTextContent := TextContent;end; procedure
TfrBrowser.FormShow(Sender: TObject);begin  if
GlobalWebView2Loader.InitializationError then   
showmessage(UTF8Encode(GlobalWebView2Loader.ErrorMessage))   else   
if GlobalWebView2Loader.Initialized then begin     
WVBrowser1.CreateBrowser(WVWindowParent1.Handle);    end    else
begin      showmessage('initialization failed');      exit;   
end;end; procedure TfrBrowser.FormResize(Sender: TObject);begin   
WVBrowser1.NavigateToString(fTextContent);end; procedure
TfrBrowser.FormClose(Sender: TObject; var CloseAction:
TCloseAction);begin   CloseAction := caFree;end; procedure
TfrBrowser.WMMove(var aMessage : TWMMove);begin  inherited;   if
(WVBrowser1 <> nil) then   
WVBrowser1.NotifyParentWindowPositionChanged;end; procedure
TfrBrowser.WMMoving(var aMessage : TMessage);begin  inherited;   if
(WVBrowser1 <> nil) then   
WVBrowser1.NotifyParentWindowPositionChanged;end;  initialization 
 GlobalWebView2Loader                := TWVLoader.Create(nil); 
 GlobalWebView2Loader.UserDataFolder :=
UTF8Decode(ExtractFileDir(Application.ExeName) + '\CustomCache'); 
 GlobalWebView2Loader.StartWebView2; end.                         
Problems are,

1)  WVBrowser executes well like TWVBrowser.Navigate or
TWVBrowser.NavigateToString well, ONLY WHEN its defaultURL has been
assigned. If it was left blank, I cannot open any page
programmatically.

2) If the contents of FormShow is moved to FormCreate, they are not
executed correctly. I can put them within OnformActivate.

3) When this Window is opened, it displays the content of
WVBrowser.defaultURL.  I assigned FormResize event, and when I resize
the Window, the content is replaced with ts. However, I cannot call
this PROGRAMMATICALLY.


Waiting for advices.

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egsuh · 2025-11-02 07:30

I do not fully understand the mechanism but I found a simplesolution.
The content should be defined before the creation of WVBrowser.
Windows Message must be playing some role, which I do not understand.

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i type    {
TfrBrowser }    TfrBrowser = class(TForm)      WVBrowser1:
TWVBrowser;      WVWindowParent1: TWVWindowParent;      procedure
Button1Click(Sender: TObject);      procedure FormActivate(Sender:
TObject);      procedure FormClose(Sender: TObject; var CloseAction:
TCloseAction);      procedure WVBrowser1AfterCreated(Sender:
TObject);   private      FTextContent: string;    public      property
HTMLText : string write FTextContent;      procedure Initialize;  
 protected      procedure WMMove(var aMessage: TWMMove);  message
WM_MOVE;      procedure WMMoving(var aMessage: TMessage); message
WM_MOVING;   end; var   frBrowser: TfrBrowser; implementation {$R
*.lfm} procedure TfrBrowser.FormClose(Sender: TObject; var
CloseAction: TCloseAction);begin   CloseAction :=
caFree;end; procedure TfrBrowser.WVBrowser1AfterCreated(Sender:
TObject);begin    WVWindowParent1.UpdateSize;    Caption := 'View
responses';    WVBrowser1.NavigateToString(Utf8Decode(FTextContent));
 // I don't know why but this should be positioned hereend; procedure
TfrBrowser.Initialize;begin   if
GlobalWebView2Loader.InitializationError then     
showmessage(UTF8Encode(GlobalWebView2Loader.ErrorMessage))   else    
if GlobalWebView2Loader.Initialized then begin       
 WVBrowser1.CreateBrowser(WVWindowParent1.Handle);      end      else
begin         showmessage('initialization failed');         exit;    
end;end; procedure TfrBrowser.Button1Click(Sender: TObject);begin   //
WVBrowser1.Navigate('http://www.alphaq.biz'); 
 WVBrowser1.NavigateToString(UTF8Decode('가설라무네'));           // Once
initialized, this works well. end; procedure
TfrBrowser.FormActivate(Sender: TObject);begin   
Initialize;end; procedure TfrBrowser.WMMove(var aMessage :
TWMMove);begin  inherited;   if (WVBrowser1 <> nil) then   
WVBrowser1.NotifyParentWindowPositionChanged;end; procedure
TfrBrowser.WMMoving(var aMessage : TMessage);begin  inherited;   if
(WVBrowser1 <> nil) then     
WVBrowser1.NotifyParentWindowPositionChanged;end; initialization 
 GlobalWebView2Loader                := TWVLoader.Create(nil); 
 GlobalWebView2Loader.UserDataFolder :=
UTF8Decode(ExtractFileDir(Application.ExeName) + '\CustomCache'); 
 GlobalWebView2Loader.StartWebView2;end. 
and calling part:

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
TForm1.Button2Click(Sender: TObject);var   ts: string;begin   ts :=
'Good morning';     with TfrBrowser.Create(nil) do begin  // this
creates Pop-up form      HTMLText := ts;                            //
the HTML content to display is assigned first.      ShowModal;       
                         // then call FormActivate.   end;end; 
It's strange that TWVBrowser is a component dropped from component
pallette, but it should be created within the program.

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egsuh · 2025-11-03 02:33

This component displays contents, but takes long sometimes --- several
seconds. But still seems this is rather tricky to use --- it does not
respond to every event handler. It seems that the operation has
something to do with Windows messages.

Anyway I prefer this to CEF4 because this needs only one file,
WebView2Loader.dll for distribution.

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egsuh · 2025-11-07 05:00

One thing I think I found --- the components needs to be focused to
operate correctly. In my case, the TFrame that contains TWVBrowser and
TWVWindowParent should be focused before any contents are provided.