MSBuild要使用properties metadata等属性必须要在Project node里加上ToolsVersion="3.5"属性，如下
<Project ToolsVersion="3.5" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
MSBuild要使用properties metadata等属性必须要在Project node里加上ToolsVersion="3.5"属性，如下
<Project ToolsVersion="3.5" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">