c# - C# 中带参数的属性

Question

在 VB.Net 中，通过在属性定义的开头提及所有参数，属性可以像在函数中一样接收参数:

Private m_Address(2) As String
 Property Address(ByVal index As Integer) As String
   Get
     If index >= 0 And index <= UBound(m_Address) Then
       Return m_Address(index)
     End If
   End Get
   Set(ByVal Value As String)
     If index >= 0 And index <= UBound(m_Address( Then
       m_Address(index) = Value
     End If
   End Set
 End Property

如果您想分配或读取属性的值，请在括号中发送所需的参数:

Dim hassn As New PersonClass()
 Dim counter As Integer
 hassn.Address(0) = "National Street"
 hassn.Address(1) = "Imbaba neighborhood"
 hassn.Address(2) = "Giza"
 For counter = 0 To 2
   MsgBox(hassn.Address(counter))
 Next

我尝试使用 C# 执行此操作，但出现此错误:

public class Geek
{
    private string[] m_address = new string[2];
    public string[int x] address // error here
    {
        get
        {
            if (index >= 0 && index < index.length)
            {
                return m_address;
            }
        }
        set {
            if (index >= 0 && index < index.length)
            {
                m_address = value;
            }
        }
    }
}

Answer 1

是的，在 C# 中没有 Parameterized Properties 这样的东西.您可以在 C# 中定义的唯一类型的参数化属性是索引器。

典型的 C# 属性只有一个默认参数 value。无论如何，属性是一组访问器，因此您可以定义这些方法而不是使用属性:

public class Geek
{
    private string[] m_address = new string[2];

    public void setAddress(int index)
    {
         if (index >= 0 && index < index.length)
         {
            m_address = value;
         }
    }

    public void getAddress(int index)
    {
        if (index >= 0 && index < index.length)
        {
           return m_address;
        }
    }
}

另一种选择是创建一个封装字段的类 Address 并定义一个接受参数的自定义索引器。

好吧，让我们看看我们如何在这里使用索引器。首先让我们为地址创建一个类或结构:

public class Address
{
   private string[] m_address = new string[2];

   public string this[int index]
   {
      get => index >= 0 && index < m_address.Length ? m_address[index] : null;
      set
      { 
          if (index >= 0 && m_address.Length > index)
          {
              m_address[index] = value;
          }
      }
   }
}

然后让我们更改您的主类以使用地址:

public class Geek
{
    public Address Address { get; } = new Address();
}

现在您可以像这样为 Address 属性使用索引器:

var hassn = new Geek();
hassn.Address[0] = "National Street";