C# WPF Change Resource On Click

My XAML is here:

<Window.Resources>
    <XmlDataProvider x:Key="rssSource" XPath="//item" Source="https://news.google.com/news?output=rss" />
</Window.Resources>

I need to change it when button click event:

<Window.Resources>
    <XmlDataProvider x:Key="rssSource" XPath="//item" Source="CHANGE WITH TEXTBOX VALUE" />
</Window.Resources>

How can i do it?

Answers

Like this maybe

       XmlDataProvider provider = (XmlDataProvider) this.FindResource("rssSource");
       provider.Source = new Uri("CHANGE WITH TEXTBOX VALUE");

Inside the button click event put this line:

((XmlDataProvider)Resources["rssSource"]).Source = new Uri("<New Source>");

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