Vista - xaml resourcedictionary

I am new to Xaml and want to create a simple Xaml file that can be used on a
windows or web app. I created a xaml file with a ResourceDictionary tag as a
root which contains a StackPanel tag that contains a button and a textbox. I
want to fill the content of the Page and the Window elements with the same
StackPanel in the ResourceDictionary Xaml file so both apps have the same
textbox and button. I have the following code in the Window constructor:
ResourceDictionary resDict = new ResourceDictionary();
Uri uriRes = new Uri("MyXaml.xaml", UriKind.Relative);

resDict.Source = uriRes;

foreach (object objResource in resDict.Values)
{
StackPanel stk = (StackPanel)objResource;
this.Content = stk;
}

This puts the textbox and button on the form, but I am unable to reference
either object in the code because it complains if I put the Name attribute in
the textbox or button tags in the ResourceDictionary Xaml file. I could get
to them with the code ((TextBox)((StackPanel)this.Content).Children[1]) but
this is not a generic solution and I won't be able to respond to their events.

How can I achieve a generic and reusable Xaml definition for a simple form?
Is this the right way or do I need to do something else. Is it possible to
achieve this with Xaml?

Please help.

Thanks,