I am using C#, but my file keeps being saved as VB

I am using C# and Dreamweaver to work on my project. But one file keeps getting be saved as VB file. If I manually change to C#, I get compilation error right away. If I change back to VB, it is working. But I cannot used VB as all other files in the project are careated with C#. Please help!!!!! Thank you so much.
compilation error --
CS1525: Invalid expression term '>'
<Parameters>
<Parameter Name="@ContentID" Value='<%# IIf((Request.QueryString("ContentID") <> Nothing), Request.QueryString("ContentID"), "") %>' Type="Integer" />
</Parameters>

The dataset and the parameters are created with Dreamweaver. How could those be invalid?
Thanks a lot for your help.