VSTO4.0为何可以兼容Excel2007

qilongjie

使用VSTO做了一个插件，第一个版本使用.NET3.5，这个版本可以装载Excel2010、Excel2013中，不兼容Excel2007.之后做了升级，将.NET版本升级为4.0，客户机只装.NET4.5就可以兼容Excel2010、2013，不兼容2007.
在客户机同时安装.NET4.0、VSTO runtime4.0之后，都能兼容。

请教：
.NET3.5下，客户机装了.NET3.5和VSTO runtime不能兼容Excel2007
为什么4.0下就能以兼容Excel2007？
请指教。

qilongjie

是我提问没说明白吗，怎么没人乐意赐教。
我的问题是，
1. 在不装VSTO runtime时，可以装在Excel2010、2013上，但Excel2007不能用，装上VSTO runtime后，Excel2007为什么可用？
2. 我建的VSTO工程是Excel2010 addnin，为什么Excel2013、Excel2007都可用？
谢谢赐教

qilongjie

查了一天的资料，找到答案了：
With Visual Studio 2010, this scenario gets better. If you target the .NET Framework 4, you can now create a single add-in that targets both Office 2007 and Office 2010, and uses features that are available only to Office 2010 (this is the “lights up” part of the title of this blog). This is possible by virtue of the new embedded interop types feature in Visual Studio 2010 (also sometimes referred to as no-PIA or by the related /link compiler option). When you compile an add-in project that targets the .NET Framework 4, by default* the type information for all the PIA types referenced in the add-in code is embedded in the add-in assembly. At run time, this type information is used to resolve calls to the underlying COM type, rather than relying on type information in the PIAs.

qilongjie

With Visual Studio 2010, this scenario gets better. If you target the .NET Framework 4, you can now create a single add-in that targets both Office 2007 and Office 2010, and uses features that are available only to Office 2010 (this is the “lights up” part of the title of this blog). This is possible by virtue of the new embedded interop types feature in Visual Studio 2010 (also sometimes referred to as no-PIA or by the related /link compiler option). When you compile an add-in project that targets the .NET Framework 4, by default* the type information for all the PIA types referenced in the add-in code is embedded in the add-in assembly. At run time, this type information is used to resolve calls to the underlying COM type, rather than relying on type information in the PIAs.