Getting errors creating ChromiumOSR programmatically

问题

I'm trying to create ChromiumOSR programmatically but I keep getting an error (access violation). Here is sample code that causes the problem:

var
pChromiumOSR: TChromiumOSR;
begin
  pChromiumOSR := TChromiumOSR.Create(Self);
  pChromiumOSR.OnLoadEnd := pChromiumOSRLoadEnd;
  pChromiumOSR.Browser.MainFrame.LoadUrl('www.google.com');
end;

The problem is that pChromiumOSR.Browser.MainFrame is always nil. If I do pChromiumOSR.load('www.google.com'); I don't get any errors but it doesn't fire the onLoadend.

Can anyone give me any suggestions on what I might be doing wrong? I'm using Delphi XE2 but not sure which version of chromium (where can I find the version?)

回答1:

Your attempt to use Load method for loading a page was correct. The other one was wrong and failed because the Browser instance was not created. It's because the TChromiumOSR was designed to be a design time component rather than to be created dynamically.

Now, the only place where the Browser instance is created is the Loaded method, which is called for a component after its parent form is loaded from a stream. And since you are creating it dynamically, the Browser instance is never created.

For some reason also the CreateBrowser method (which creates the Browser instance) is declared as private, which complicates its calling a bit (unless you decide to modify the source and make it public). If you don't want to change your DCEF source code, you can use a class helper to provide access to the CreateBrowser method:

uses
  ceflib, cefvcl;

type
  TChromiumOSRHelper = class helper for TCustomChromiumOSR
  public
    procedure CreateBrowserInstance;
  end;

implementation

{ TChromiumOSRHelper }

procedure TChromiumOSRHelper.CreateBrowserInstance;
begin
  Self.CreateBrowser;
end;

Then to create a Browser instance add the CreateBrowserInstance call before the first accessing the Browser instance (which is here the Load method):

var
  pChromiumOSR: TChromiumOSR;
begin
  pChromiumOSR := TChromiumOSR.Create(Self);
  pChromiumOSR.OnLoadEnd := pChromiumOSRLoadEnd;
  pChromiumOSR.CreateBrowserInstance;
  pChromiumOSR.Load('www.google.com');
end;

来源：https://stackoverflow.com/questions/20251111/getting-errors-creating-chromiumosr-programmatically

标签

Delphi

tchromium