Error in Generic method: 'T' does not contain a definition for...

[J Miro]

When I call the Generic method ShowName in the following code, I get the
error message "'T' does not contain a definition for 'Name'." Does anyone
know why? Thanks in advance. Jay.

//------------------------------------
using System;
using System.Collections.Generic;

namespace ConsoleApp1
{
class GenericsTest
{
static void Main(string[] args)
{
Person person = new Person();
person.Name = "John";
ShowName<Person>(person);
}

static void ShowName<T>(T someObject)
{
Console.WriteLine(someObject.Name);
}
}


public class Person
{
public string Name = "";
}
}
//-----------------------------------

 

[Nicholas Paldino [.NET/C# MVP]]

Generics in C# are not like C++, in that the type T is not resolved at
compile-time in order to determine whether or not a class has certain
members. Because of this, you will have to use reflection to call the
member "Name", or you can use a constraint, defining an interface or base
class which exposes the member, like so:

public interface IPerson
{
string Name {get; set;}
}

public class Person : IPerson
{}

static void ShowName<T>(T someObject) where T : IPerson
{
Console.WriteLine(someObject.Name);
}

Hope this helps.

 

[J Miro]

Thanks so much Nicholas for your prompt response.

Jay.

Generics in C# are not like C++, in that the type T is not resolved at
compile-time in order to determine whether or not a class has certain
members. Because of this, you will have to use reflection to call the
member "Name", or you can use a constraint, defining an interface or base
class which exposes the member, like so:

public interface IPerson
{
string Name {get; set;}
}

public class Person : IPerson
{}

static void ShowName<T>(T someObject) where T : IPerson
{
Console.WriteLine(someObject.Name);
}

Hope this helps.


--
- Nicholas Paldino [.NET/C# MVP]
- (e-mail address removed)

When I call the Generic method ShowName in the following code, I get the
error message "'T' does not contain a definition for 'Name'." Does anyone
know why? Thanks in advance. Jay.

//------------------------------------
using System;
using System.Collections.Generic;

namespace ConsoleApp1
{
class GenericsTest
{
static void Main(string[] args)
{
Person person = new Person();
person.Name = "John";
ShowName<Person>(person);
}

static void ShowName<T>(T someObject)
{
Console.WriteLine(someObject.Name);
}
}


public class Person
{
public string Name = "";
}
}
//-----------------------------------