如何检查继承的属性是否是类(子类)的一部分

Question

我正在尝试创建一个泛型函数，该函数可以通过查看MemberExpression的Member并在Type中找到它来判断该属性是否存在于该类中。它适用于普通属性，但对于继承属性，它找不到它们。

class Person {
public string FirstName {get;set;}
public string LastName {get;set;}       
}
class Student : Person {
public string StudentID {get;set;}
}
public static void Main()
{
bool test1 = IsPropertyPartOfClass<Student, string>(x => x.StudentID);
Console.WriteLine("Testing StudentID property");
if (test1)
Console.WriteLine("tProperty is part of Class");
else
Console.WriteLine("tProperty is not part of Class");
bool test2 = IsPropertyPartOfClass<Student, string>(x => x.FirstName);
Console.WriteLine("Testing FirstName property");
if (test2)
Console.WriteLine("tProperty is part of Class");
else
Console.WriteLine("tProperty is not part of Class");
}
public static bool IsPropertyPartOfClass<T, R>(Expression<Func<T, R>> expPropSel){
MemberInfo mem_info_from_exp = ((MemberExpression)((LambdaExpression)expPropSel).Body).Member;
return typeof(T).GetProperties().Where(x=> x == mem_info_from_exp).Any();
}

输出：

Testing StudentID property
Property is part of Class
Testing FirstName property
Property is not part of Class

更新：

在@NetMage的帮助下，我能够修改我的方法。请注意，我的方法现在还涵盖了表达式可能属于不同子类而T参数可能表示不同子类的情况。

var employeeObj = new Employee(); // here Employee is also inherited from Person class
trickyTest = IsPropertyPartOfClass<Student, string>(x => employeeObj.FirstName);

在上面的例子中，我们希望函数返回false。

public static bool IsPropertyPartOfClass<T, R>(Expression<Func<T, R>> expPropSel) {
MemberInfo mem_info_from_exp = ((MemberExpression)((LambdaExpression)expPropSel).Body).Member;
Type sourceType = ((MemberExpression)((LambdaExpression)expPropSel).Body).Expression.Type;
return typeof(T)
.GetProperties()
.Where(x=> 
sourceType == typeof(T) &&
(
(x == mem_info_from_exp) || 
(
x.Name == mem_info_from_exp.Name &&
x.Module.Equals(mem_info_from_exp.Module) && 
x.MetadataToken == mem_info_from_exp.MetadataToken
)
)
)
.Any();
}

Answer 1

lambda 的MemberInfo和类型的PropertyInfos 之间的ReflectedType不同 - 也许你应该使用HasSameMetadataDefinitionAs？

请参阅此处的讨论，了解添加它的原因。

Answer 2

可能 IsPropertyPartOfClass 方法也可以检查基属性

public static bool IsPropertyPartOfClass<T, R>(Expression<Func<T, R>> 
expPropSel)
{
MemberInfo memInfoFromExp = ((MemberExpression) expPropSel.Body).Member;
var memberInfo = typeof(T).BaseType;
return typeof(T).GetProperties().Any(x => x == memInfoFromExp || 
memberInfo != null && memberInfo.GetProperties().Any(x => x == 
memInfoFromExp));
}