<p>I have a number of custom controls that I am trying to enable designer support for. The signature looks something like the following:</p>

<pre><code>[ToolboxData("&lt;{0}:MyDropDownList runat=\"server\" CustomProp="123"&gt;&lt;/{0}:MyDropDownList&gt;")]
public class MyDropDownList: DropDownList
{
   ... code here
}
</code></pre>

<p>This works fine, but when I drag a control onto the page from the toolbox, the TagPrefix that gets added is "cc1":</p>

<pre><code>&lt;%@ Register Assembly="DBMClientPortal.Controls" Namespace="DBMClientPortal.Controls"
    TagPrefix="cc1" %&gt;
</code></pre>

<p>Obviously it is somewhat irrelevant what that TagPrefix is... it works as it stands, but I figured I <em>must</em> be able to change it somehow and curiosity got the better of me...</p>

<p>Anyone know how to define what the TagPrefix will be set to when dragging a custom control onto a page in visual studio?</p>

<p>Thanks,
Max</p>

It looks something like this:
```
```
[assembly:TagPrefix("MyControls","RequiredTextBox")]
```
```
and
here's
some more info about it.