Mixed Mode Error when building in Release Mode

Question

I have c# asmx service project that was running on framework 2 with vs 2008 Now i have updated it to framework 4 with vs 2010

when i build dll in debug mode it compi

Answer 1

I got it working By going to Project-> Right Click-> Properties-> Build->Generate Serialiazation Assembly Change Value here "Auto" to Off and build on release mode it now works

Answer 2

You would have to put it inside configuration tag check the link http://msdn.microsoft.com/en-us/library/bbx34a2h.aspx, which was also there in previous link answer.

Answer 3

Do you have unmanaged code in your solution, or do you build against one?
We had run into such issue at work when we moved to work with VS2010 and .net 4.
What worked for us was adding App.config file to the project which contains the following:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <startup useLegacyV2RuntimeActivationPolicy="true">
    <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/>
  </startup>
</configuration>