.NET 多版本引用

​在C#的项目中经常要引用各种DLL，有时就要引用其他版本的DLL，此时就会产生问题。

前段时间一个同事在.NET4.0版本的project上引用SQL Server SMO，就出现了这种问题，他本地机器上安装的是SQL Server 2008，所以他引用的SMO是.NET2.0，此时就出现了版本问题。

 

错误信息：

Mixed mode assembly is built against version 'v2.0.50727' of the runtime and cannot be loaded in the 4.0 runtime without additional configuration information.

解决办法：

http://connect.microsoft.com/SQLServer/feedback/details/643811/net-4-0-compatible-smo

 

add the following entry to the app.config file and it should work.

<startup useLegacyV2RuntimeActivationPolicy="true">
    <supportedRuntime version="v4.0"/>
</startup>

For your dev machine can you please confirm the following:
    1. What is the version of .NET on that machine?
    2. Does the app.config file on the dev machine has the above given entry?

经试验果然解决了版本问题。