DBSET和ObjectQuery如何转换？

Question

我用EF4.1，查询实体时候是这样

this.context.Set<STEP>()：

这是个System.Data.Entity.DbSet对象，

有没有办法转换成ObjectQuery<STEP>？

因为我用的一个扩展方法是针对ObjectQuery的：

public static ObjectQuery<T> Include<T>(this ObjectQuery<T> query, Expression<Func<T, object>> exp) {
Expression body = exp.Body;
MemberExpression memberExpression = (MemberExpression)exp.Body;
string path = GetIncludePath(memberExpression);
return query.Include(path);
}

private static string GetIncludePath(MemberExpression memberExpression) {
string path = "";
if (memberExpression.Expression is MemberExpression) {
path = GetIncludePath((MemberExpression)memberExpression.Expression) + ".";
}
PropertyInfo propertyInfo = (PropertyInfo)memberExpression.Member;
return path + propertyInfo.Name;
}

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they say nothing last forever