the property 'Content' is set more than once

Question

I am having the following XAML code, which throws error following error pointing to line# 16.

the property \'Content\' is set more than once

Answer 1

The Content property is normally mapped to whatever is between the and tags, e.g.

    This stuff is set to the Content property

But it can also be set like a normal property, e.g.

In your example you are doing both by setting the Content property on line 15 like a normal property and again on line 16 between the tags. I'm guessing you will want to get rid of the Content="Viewer" on line 15 to get the output you are looking for.