Question

我在我的mvc应用程序中编写了以下代码。

public class TestController : Controller
{
    public ActionResult StronglyTypedView()
    {
      var obj = new MvcRouting.Models.Student();
      obj.age = 24;
      obj.name = "prab";
      ViewData.Model = obj;
      return View();
    }
}

在上面的代码中，ViewData是ControllerBase类的属性，而Model是ViewDataDictionary类的属性。我在下面的代码中试过但是我得到了property1中的null值，如何解决？

 public interface Iface1
 {       
    int age { get; set; }
 }
 public class classA : Iface1
 {       
   public int age { get; set; }
 }
 public abstract class classB
 {       
    public classA Property1 { get; set; }
 }
 public class TEST : classB
 {
   public void test()
   {          
      Property1.age = 24;
   }
   public static void Main()
   {
     TEST obj = new TEST();
     obj.test();
     Console.Read();
   }
 }

Answer 1

您将获得空引用异常，因为您需要在Property1中初始化classB

 public interface Iface1
 {       
    int age { get; set; }
 }
 public class classA : Iface1
 {       
   public int age { get; set; }
 }
 public abstract class classB
 {       
    public classA Property1 { get; set; }
 }
 public class TEST : classB
 {
   public void test()
   {    
      if(Property1 == null)
      {
          Property1 = new classA();
      }

      Property1.age = 24;
   }
   public static void Main()
   {
     TEST obj = new TEST();
     obj.test();
     Console.Read();
   }
 }

Answer 2

改为使用它。

public abstract class classB
{
 public classA Property1 { get; set; }

 public classB()
 {
   Property1 = new classA();
 }
}

Answer 3

在设置其属性之前，您忘记初始化Property1。

public class TEST : classB
{
   public void test()
   {    
      Property1 = new classA();
      Property1.age = 24;
   }
   public static void Main()
   {
     TEST obj = new TEST();
     obj.test();
     Console.Read();
   }
}

如何从派生类初始化基类属性？

3 个答案: