# The tag 'DisplayObject' does not exist in XML namespace

**URL:** <https://forum.kirupa.com/t/the-tag-displayobject-does-not-exist-in-xml-namespace/313037>\
**Category:** programming\
**Created:** [August 18, 2010, 2:23pm UTC](https://forum.kirupa.com/t/the-tag-displayobject-does-not-exist-in-xml-namespace/313037 "2010-08-18T14:23:46Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![DashMasterful](https://avatars.discourse-cdn.com/v4/letter/d/59ef9b/32.png) [@DashMasterful](https://forum.kirupa.com/u/DashMasterful)\
**Post date:** [August 18, 2010, 2:23pm UTC](https://forum.kirupa.com/t/the-tag-displayobject-does-not-exist-in-xml-namespace/313037/1 "2010-08-18T14:23:46Z")

</div>

I have a class called DisplayObject, its namespace is SilverlightClasses.Display  
This is in a .dll file called SilverlightClasses.dll

I created a new project called InfluencecTest.When I try to create a Button and have it inherit from the DisplayObject class, I run into problems

I open up DoButton.xaml, and have it extend the DisplayObject class, take note of the myClassPath namespace

\<myClassPath:DisplayObject  
xmlns=“[http://schemas.microsoft.com/winfx/2006/xaml/presentation](http://schemas.microsoft.com/winfx/2006/xaml/presentation)”  
xmlns:x=“[http://schemas.microsoft.com/winfx/2006/xaml](http://schemas.microsoft.com/winfx/2006/xaml)”  
xmlns:d=“[http://schemas.microsoft.com/expression/blend/2008](http://schemas.microsoft.com/expression/blend/2008)”  
xmlns:mc=“[http://schemas.openxmlformats.org/markup-compatibility/2006](http://schemas.openxmlformats.org/markup-compatibility/2006)”  
xmlns:myClassPath =“clr-namespace:SilverlightClasses.Display;assembly=SilverlightClasses”  
mc:Ignorable=“d”  
x:Class=“InfluenceTest.DoButton”  
d:DesignWidth=“166” d:DesignHeight=“41”\>

```
&lt;Grid x:Name="LayoutRoot"&gt;
	&lt;Button Content="Button"/&gt;
&lt;/Grid&gt;

```

\</myClassPath:DisplayObject\>

This doesn’t work: error below, what am I doing wrong. DisplayObject does in fact exist because I can instantiate it directy inside any .cs file, xaml is the one that gives me problems

Error 1 The tag ‘DisplayObject’ does not exist in XML namespace ‘clr-namespace:SilverlightClasses.Display;assembly=SilverlightClasses’.