Question

这是构造函数：

 public PartyRoleRelationship(PartyRole firstRole, PartyRole secondRole)
        {
            if (firstRole == secondRole)
                throw new Exception("PartyRoleRelationship cannot relate a single role to itself.");

            if (firstRole.OccupiedBy == null || secondRole.OccupiedBy == null)
                throw new Exception("One or both of the PartyRole parameters is not occupied by a party.");

            // Connect this relationship with the two roles.
            _FirstRole = firstRole;
            _SecondRole = secondRole;


            T = _FirstRole.GetType().MakeGenericType();

            _SecondRole.ProvisionRelationship<T>(_FirstRole); // Connect second role to this relationship.
        }

在最后一行，它在_SecondRole上调用ProvisionRelationship，它给了我运行时错误：无法找到类型或名称空间“T”...

我如何（a）正确分配T，或（b）使用构造函数传递泛型？我一直在查看相当多的帖子，但可能由于缺乏理解而遗漏了一些内容。任何人对此的帮助将不胜感激。

Answer 1

你的课程必须是通用的。所以PartyRoleRelationship需要看起来像这样：

public class PartyRoleRelationship<T>
{
    public PartyRoleRelationship(T arg, ...)
    {
    }
}

在此处阅读有关泛型类的更多信息：

http://msdn.microsoft.com/en-us/library/sz6zd40f(v=vs.80).aspx

http://msdn.microsoft.com/en-us/library/ms379564(v=vs.80).aspx

编辑：

你可能会简化你的代码并按照这样做：

public class RoleRelationship<T>
{
    public RoleRelationship(T firstRole, T secondRole)
    {
        if (firstRole.OccupiedBy == null || secondRole.OccupiedBy == null)
            throw new Exception("One or both of the Role parameters is not occupied by a party.");

        // Connect this relationship with the two roles.
        _FirstRole = firstRole;
        _SecondRole = secondRole;

        _SecondRole.ProvisionRelationship<T>(_FirstRole);
    }
}

Answer 2

创建泛型类，其中泛型类型T是基类PartyRole的类型：

public class PartyRoleRelationship<T> where T : PartyRole 
{
     T _FirstRole;
     T _SecondRole;

     public PartyRoleRelationship(T role1, T role2) {
         _FirstRole = role1;
         _SecondRole = role2;
         role1.ProvisionRelationship(role2)
     }

     public ProvisionRelationship(T otherRole) {
          // Do whatever you want here
     }

}

Answer 3

如果您静态知道_FirstRole的类型（是PartyRole吗？），您可以使用它：

_SecondRole.ProvisionRelationship<PartyRole>(_FirstRole);

如何将泛型类型参数传递给从构造函数调用的方法？

3 个答案: