# Instance Inheriting

An**\<Instance/\>**can be a base type of another**\<Instance/\>**. These two instances are required to be in the same XML resource, or the base type is required to be in[one of the dependency](../../.././gacui/xmlres/cxrr.md)specified in[the Metadata configuration](../../.././gacui/xmlres/cgc.md).

Typically, you don't want your**\<Instance/\>**to be in the default namespaces, so it is very common to use[xmlns:NAMESPACE](../../.././gacui/xmlres/instance/namespaces.md)for the base type like:
```
<Resource>
  <Instance name="BaseInstanceResource">
    <Instance ref.Class="sample::MyBaseInstance">
      <Window/>
    </Instance>
  </Instance>
  
  <Instance name="DerivedInstanceResource">
    <Instance ref.Class="sample::MyDerivedInstance" xmlns:sample="sample::*">
      <sample:MyBaseInstance/>
    </Instance>
  </Instance>
</Resource>
```


Please check out[Cross XML Resource References](../../.././gacui/advanced/cxrr.md)for details.

