出现这样的问题主要是由低版本的VS用高版本的VS运行导致的。
<system.codedom>
<compilers>
<compiler
language="c#;cs;csharp"
extension=".cs"
type="Microsoft.CSharp.CSharpCodeProvider,System,
Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"
warningLevel="4">
<providerOption
name="CompilerVersion"
value="v4.0"/>
<providerOption
name="WarnAsError"
value="false"/>
</compiler>
<compiler
language="vb;vbs;visualbasic;vbscript"
extension=".vb"
type="Microsoft.VisualBasic.VBCodeProvider,
System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"
warningLevel="4">
<providerOption
name="CompilerVersion"
value="v4.0"/>
<providerOption
name="OptionInfer"
value="true"/>
<providerOption
name="WarnAsError"
value="false"/>
</compiler>
</compilers>
</system.codedom>