<p>I have recently installed .net 3.5 SP1.  When I deployed a compiled web site that contained a form with its action set:</p>

<pre><code>&lt;form id="theForm" runat="server" action="post.aspx"&gt;
</code></pre>

<p>I received this error.<br>
Method not found: 'Void System.Web.UI.HtmlControls.HtmlForm.set_Action(System.String)'.<br>
If a fellow developer who has not installed SP1 deploys the compiled site it works fine.  Does anyone know of any solutions for this?</p>

I don't know the specific solution, but HtmlForm.set_Action() is a function the compiler creates that acts as the setter for a property called Action.
When you do:
```
```
public String Action { set { DoStuff(); } }
```
```
The
set
code actually becomes a function called
set_Action
.
I know it's not the best answer, but I hope it helps you find the source of your problems!