为什么我的课什么？ [英] Why is my class nothing?

问题描述

我有一个.NET 2010项目。在这里面，我创建了一个基本的用户类。实例并成功地用数据填充它。它是这样做的，如果我悬停在类的整个时间，它说，这不算什么，即使它填补其属性。后来，它软管我的UI，尽管酒店有一个值，它说的类是什么。

I DO instatiate类...

昏暗oExtendedUser作为新ExtendedUser

和这里是班组长定义...

 公共类ExtendedUser
    继承System.Web.Security.MembershipUser    的Public Sub New（）
        _Role =新角色    结束小组    公共属性ExtendedUserID作为的Int32
    公共属性名字作为字符串
    公共属性名字作为字符串
    公共属性电话作为字符串
    公共财产的userid的Guid
    公共属性角色作为角色
    公共属性用户名（）作为字符串
    公共财产密码（）作为字符串
    公共财产SecurityQuestion（）作为字符串
    公共财产SecurityAnswer（）作为字符串
末级
 

我改变了类。我加MyBase.New（），但问题仍然存在。在用户界面上，这里是code即单击按钮时执行。署长已作为一个亲preTY，ExtendedUSer

 昏暗oCase作为新BE.Case
 昏暗oDirector作为新BE.Director
 oDirector = SessionManager.Director'的值是这里
 oCase.Investigator.ExtendedUserID = oDirector.ExtendedUser.ExtendedUserID
 

这里是主任...

 公共班主任    的Public Sub New（）
        _ExtendedUser =新ExtendedUser    结束小组    公共属性ID作为的Int32
    公共属性ExtendedUser作为ExtendedUser末级
 

解决方案

您得到了由覆盖的ToString欺骗。
你的对象存在，但覆盖ToString方法：的MembershipUser的ToString

要验证这一行为，用一个简单的类试试吧：

VB.NET

 公共类测试
   公共属性TestString视为字符串   公共覆盖功能的ToString（）作为字符串
      返回Me.TestString
   结束功能末级
 

C＃

 公共类测试
{
    公共字符串的TestString {搞定;组; }    公共重写字符串的ToString（）
    {
        返回this.TestString;
    }
}
 

有了这个code，手表将告诉你一个实例化测试不了了之，因为的ToString值将一无所获。对象存在，但Visual Studio是使用ToString方法来填充值字段，而在这一点上是没有。

VB.NET

 公共类测试
   公共财产的TestString的String =   公共覆盖功能的ToString（）作为字符串
      返回Me.TestString
   结束功能末级
 

C＃

 公共类测试
{
      公开测试（）
      {
          this.TestString =;
      }    公共字符串的TestString {搞定;组; }    公共重写字符串的ToString（）
    {
        返回this.TestString;
    }}
 

有了这个code，你会得到一个空字符串。

要回到你的code，你不能扩展的MembershipUser如此简单，你必须遵循这一准则：的如何：实现自定义成员资格用户。由于很多事情不会与您的实际推广工作（例如，您的用户名阴影的基地之一）。

请参阅这个问题为好。还有更简单的方法来扩展你的用户实体不是继承。

I have a .NET 2010 project. In it, I create a basic user class. Instantiate it and successfully fill it with data. The entire time it is doing this, if I hover over the class, it says it is nothing, even as it fills its properties. Later on, it hoses me in the UI, even though the property has a value it says the class is nothing.

I DO instatiate the class...

Dim oExtendedUser As New ExtendedUser

and here is the classs definition...

Public Class ExtendedUser
    Inherits System.Web.Security.MembershipUser

    Public Sub New()
        _Role = New Role

    End Sub

    Public Property ExtendedUserID As Int32
    Public Property FirstName As String
    Public Property LastName As String
    Public Property Phone As String
    Public Property UserID As Guid
    Public Property Role As Role
    Public Property UserName() As String
    Public Property Password() As String
    Public Property SecurityQuestion() As String
    Public Property SecurityAnswer() As String
End Class

I changed the class. I added MyBase.New() but the problem persists. On the UI, here is the code that executes when the button is clicked. Director has, as a proprety, ExtendedUSer

Dim oCase As New BE.Case
 Dim oDirector As New BE.Director
 oDirector = SessionManager.Director 'the values are here
 oCase.Investigator.ExtendedUserID = oDirector.ExtendedUser.ExtendedUserID

And here is the Director...

Public Class Director

    Public Sub New()
        _ExtendedUser = New ExtendedUser

    End Sub

    Public Property ID As Int32
    Public Property ExtendedUser As ExtendedUser

End Class

解决方案

You got tricked by the ToString Override. Your object exists but it overrides the ToString Method : MembershipUser.ToString

To validate this behavior, try it with a simple class :

VB.NET

Public Class Test
   Public Property TestString As String 

   Public Overrides Function ToString() As String
      Return Me.TestString
   End Function

End Class

C#

public class Test
{
    public string TestString { get; set; }

    public override string ToString()
    {
        return this.TestString;
    }
}

With this code, the Watch will show you an instanciated Test to Nothing, because ToString value will be Nothing. The object exist, but Visual Studio is using the ToString Method to populate the value field, and at this point it is Nothing.

VB.NET

Public Class Test
   Public Property TestString As String = ""

   Public Overrides Function ToString() As String
      Return Me.TestString
   End Function

End Class

C#

public class Test
{
      public Test()
      {
          this.TestString = "";
      }

    public string TestString { get; set; }

    public override string ToString()
    {
        return this.TestString;
    }

}

With this code you'll get an empty string.

To get back to your code, you cannot extend the MembershipUser so simply, you have to follow this guideline : How to: Implement a Custom Membership User. As many things won't work with your actual extension (For example, your username shadowing the base one).

See this question as well. There are easier ways to extend your user "entity" than inheritance.

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