IEnumerable<T> models = ...

// Special handling of MySpecialModel
if (filterString != null && typeof(MySpecialModel).IsAssignableFrom(typeof(T)))
{
    var filters = filterString.Split(...);
    models = 
        from m in models.Cast<MySpecialModel>()
        where (from t in m.Tags
               from f in filters 
               where t.IndexOf(f,StringComparison.CurrentCultureIgnoreCase) >= 0
               select t)
              .Any()
        select (T)m;
}

但是我在最后一行得到例外

Cannot convert type 'MySpecialModel' to 'T'

如果我更改代码而不是强制转换,我会收到此错误.

The type parameter 'T' cannot be used with the 'as' operator because it does not have a class type constraint nor a 'class' constraint.

我在这里错过了什么？

更新

这个类需要可以采用任何类型参数,包括结构和内置类型,因此在我的情况下,通用约束不是一个合适的解决方案.