Regarding udione's solution for WebBrowser memory leak

This code was asked by udione in response to a longstanding question about memory leaks in the WebBrowser control in .Net .

//dispose to clear most of the references 
this.webbrowser.Dispose(); 
BindingOperations.ClearAllBindings(this.webbrowser); 

//using reflection to remove one reference that was not removed with the dispose  
var field = typeof(System.Windows.Window).GetField("_swh", System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance); 

var valueSwh = field.GetValue(mainwindow); 

var valueSourceWindow = valueSwh.GetType().GetField("_sourceWindow", System.Reflection.BindingFlags.Instance | System.Reflection.BindingFlags.NonPublic).GetValue(valueSwh); 

var valuekeyboardInput = valueSourceWindow.GetType().GetField("_keyboardInputSinkChildren", System.Reflection.BindingFlags.Instance | System.Reflection.BindingFlags.NonPublic).GetValue(valueSourceWindow); 

System.Collections.IList ilist = valuekeyboardInput as System.Collections.IList; 

lock(ilist) 
{ 
    for (int i = ilist.Count-1; i >= 0; i--) 
    { 
        var entry = ilist[i]; 
        var sinkObject = entry.GetType().GetField("_sink", System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance); 
        if (object.ReferenceEquals(sinkObject.GetValue(entry), this.webbrowser.webBrowser)) 
        { 
            ilist.Remove(entry); 
        } 
    } 
}  

      

        
        
        
      

    

1) Third line,

BindingOperations.ClearAllBindings(this.webbrowser); 

      

        
        
        
      

    

won't compile for me. What is the type this.webbrowser

? I assumed it was WebBrowser

, but this method requires System.Windows.DependencyObject

.

2) In line

var valueSwh = field.GetValue(mainwindow);

      

        
        
        
      

    

what is it mainwindow

? Form containing browser control?

3) In the sixth line from the bottom

if (object.ReferenceEquals(sinkObject.GetValue(entry), this.webbrowser.webBrowser))  

      

        
        
        
      

    

what is the type this.webbrowser.webBrowser

? I don't see the type field WebBrowser

in the type WebBrowser

. Is this just a typo?

Thanks for any help.