Question

I have a class for my data, MyData, and I’m accessing it in my gui by data binding.

I decided to set the DataContext of the main panel in my window to an instance of this object so I could bind my various controls to it’s members. So I could easily reference it in my XAML, I created an instance of MyData in Window.Resources like so:

<local:MyData x:Key="myDataInstance"/>

Then I get a reference of this for my code because I need it there sometimes too.

MyData myDataInstance;

public MainWindow()
{
    InitializeComponent();
    myDataInstance = (MyData)FindResource("myDataInstance");
}

This works well, but I also can load another instance of MyData by deserializing it from file.

myDataInstance = (myData)serializer.Deserialize(fileStream);

I thought I could simply reassign myDataInstance in the code like this, but that doesn’t seem to be working since my gui doesn’t change to reflect the new data. I think reassigning is breaking the link between the main panel’s DataContext and myDataInstance.

1. Is it possible to reassign an object
   declared in xaml as I have?
2. From XAML, is it possible to access
   members declared only in the code
   (the opposite of FindResource())?
3. If so, how?

Thanks. (btw, Of course I can use other methods to easily solve this problem, but I’m also just interested in the answer to this question.)

Answer 1

You could try

public class MainWindow {

...
  void UpdateResource()
  {
     myDataInstance = (myData)serializer.Deserialize(fileStream);
     this.Resources["myDataInstance"] = myDataInstance;
  }   
}

then make sure that where ever you reference your resource you use a DynamicResource reference rather than a StaticResource reference.

Adding items to Resource dictionaries and using DynamicResource references is, as far as I know, the only way of making things in code available to XAML.