具有泛型类型的 C# 属性
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C# Property with Generic Type
提问by youwhut
I have a class:
我有一堂课：
public class class1
{
public string Property1 {get;set;}
public int Property2 {get;set;}
}
Which will be instantiated:
哪个将被实例化：
var c = new class1();
c.Property1 = "blah";
c.Property2 = 666;
So bear with me (I am new to generics), I need another class with a property of a generic type so that Property1 or Property2 can be used to set Property3:
所以请耐心等待（我是泛型的新手），我需要另一个具有泛型类型属性的类，以便 Property1 或 Property2 可用于设置 Property3：
public class Class2
{
public GenericType Property3 {get;set;}
}
I want to be able to:
我希望能够：
var c2 = new class2();
c2.Property3 = c1.Property2 // Any property of any type.
采纳答案by JonH
@bytenik I think the originator is asking that class3 be defined to contain a generic property. That way when he / she has a property from class1 or class2 which in this case is a string / int that class3's property could handle either case.
@bytenik 我认为发起者要求将 class3 定义为包含通用属性。这样，当他/她拥有 class1 或 class2 的属性时，在这种情况下是一个 string/int，而 class3 的属性可以处理任何一种情况。
public class Class3<T>
{
public T Property3 {get;set;}
}
I think the intent is the poster wants to do this:
我认为意图是海报想要这样做：
Class3.Property3 = Class2.Property2
I think the poster will need to cast it to type T for this to work though.
我认为海报需要将其转换为 T 才能正常工作。
Look at the link that was posted for an example: Making a generic property
查看示例中发布的链接：Making a generic property
Here is what you can do:
您可以执行以下操作：
namespace GenericSO
{
public class Class1
{
public int property1 { get;set;}
}
public class Class2<T>
{
public T property2 { get; set; }
}
class Program
{
static void Main(string[] args)
{
Class1 c1 = new Class1();
c1.property1 = 20;
Class2<int> c2 = new Class2<int>();
c2.property2 = c1.property1;
}
}
}
Notice how your template property2 gets the value of property1. You have to tell it what kind of generic.
请注意您的模板 property2 如何获取 property1 的值。你必须告诉它什么样的泛型。
回答by Vitaliy Liptchinsky
public class class1<T>
{
public T Property3 {get;set;}
}
Regarding to edited version of the question:
关于问题的编辑版本：
If you need a property, which can be set with any type, the most reasonable solution here is to simply use property of type Object. For C# compiler there is no way to find out instance of which exactly type you've previously pushed into property setter.
如果你需要一个可以设置为任何类型的属性，这里最合理的解决方案是简单地使用 Object 类型的属性。对于 C# 编译器，无法找出您之前推送到属性设置器中的确切类型的实例。
回答by Matt Breckon
I think you may have misunderstood generics. Another word that could be used is "template" but that is avoided because it is used for more advanced things in C++.
我想你可能误解了泛型。另一个可以使用的词是“模板”，但要避免使用，因为它用于 C++ 中更高级的东西。
The following will create a generic class of a currently undefined type T.
下面将创建一个当前未定义类型 T 的泛型类。
public class Class2<T>
{
public T Property3 { get; set; }
}
To use this you need to specify the missing type:
要使用它，您需要指定缺少的类型：
var x = new Class2<int>();
This will create an object that has a property Property3 that is of type int.
这将创建一个具有 int 类型的属性 Property3 的对象。
... or ...
... 或者 ...
var y = new Class2<string>();
This will create an object that has a property Property3 that is of type string.
这将创建一个具有字符串类型属性 Property3 的对象。
From your question I believe you actually want a type where you can assign any type to it at runtime, but this is not what generics provide.
根据您的问题，我相信您实际上想要一种可以在运行时为其分配任何类型的类型，但这不是泛型提供的。
