C# Save image from HTML page in WebBrowser control

So you have a C# windows application, a WebBrowser control inside it, and once you navigated to a webpage, you want to save the images inside the loaded HTML webpage.

The best solution I found here: http://stackoverflow.com/questions/2566898/save-images-in-webbrowser-control-without-redownloading-them-from-the-internet/8397454#8397454

The main ideas are:

- Add a reference in your project to Microsoft.mshtml (Project -> Add reference -> GAC -> Microsoft.mshtml).

- Add a 'using' statement at the top of your .cs program:

using mshtml;

- Use the following code to save all images in the HTML document

  IHTMLDocument2 doc = (IHTMLDocument2)WebBrowser1.Document.DomDocument; // gets the dom document of our object WebBrowser1
  IHTMLControlRange imgRange = (IHTMLControlRange) ((HTMLBody) doc.body).createControlRange(); // setting up the controls so we can copy/paste the HTML image objects

  foreach (IHTMLImgElement img in doc.images) // walk through all the images inside the dom document
  {
    imgRange.add((IHTMLControlElement) img); // set up which image (the current one) we are controlling
    imgRange.execCommand("Copy", false, null); // copy the current controlled image
    using (Bitmap bmp = (Bitmap) Clipboard.GetDataObject().GetData(DataFormats.Bitmap)) // create a bitmap object
    {
      bmp.Save(@"C:\downloadedimages\"+img.nameProp); // save the bitmap object to this path on our harddrive
    }
  }
 
Please note the WebBrowser1 name - you must change this to your WebBrowser control name.
Also note the path to where the image is saved - some security measures should be taken here against unwanted file names, executables, etc. as well as making sure the path points to the correct location on your hard drive.

This saves the time and network traffic of re-downloading the image again. There is an alternative to get/reconstruct the absolute image source URL, reading again and then writing the contents in a local file. This didn't work for me as i didn't want to download the image again. There are some server setting which also check for an existing session or cookie, or referrer, by which a direct access to the image is prevented, so the alternative may not work.

The current method is fastest, and it's most intuitive, just as you would do it yourself - right click and save the image from any webpage. Of course, if the 'right-click' is not disabled through Javascript or other method, which in our case is bypassed :)

Save your form before you go (onbeforeunload)

So, the onbeforeunload action.

This doesn't seem to have too many options. It acts differently in the different browsers, and no, in Firefox 4 or later you cannot change in any way the browser's security confirmation box ("Note that in Firefox 4 and later the returned string is not displayed to the user." - https://developer.mozilla.org/en/DOM/window.onbeforeunload ). In Firefox, the confirmation box invariably says: "this page is asking you to confirm that you want to leave data you have entered may not be saved".

So, once the onbeforeunload action is set, one can just show the browser's default confirmation dialog box or add another (underline - another) confirmation or other kind of dialog box. One can't remove or skip the browser's default confirmation box.

Here's my code:


global_form_changed = true;

window.onbeforeunload = function (e) {
e = e || window.event;

ret = global_form_changed?"You have not saved your contents. Are you sure you want to leave?":null;

// For IE and Firefox prior to version 4
if (e) {
e.returnValue = ret;
}

// For Safari
return ret;
};



I'm using the global global_form_changed variable so that i can either ask the user to save the content or not ask anything, depending on whether the user has actually made any changes to the form or not.
I'm modifying my global_form_changed like this:
On every input within the form, i'm setting the onchange attribute with this:
'onchange="global_frm_edit_changed = true"'

Of course there are various other ways to see if the form has actually changed or not.