对象初始化器

• 命名类型

   Dim someInstance As New SomeClass(argument) With {
       .Member1 = value1,
       .Member2 = value2
       '...
   }
  

  相当于

   Dim someInstance As New SomeClass(argument)
   someInstance.Member1 = value1
   someInstance.Member2 = value2
   '...
  

• 匿名类型 （选项推断必须打开）

    Dim anonymousInstance = New With {
        .Member1 = value1,
        .Member2 = value2
        '...
    }
  

  虽然类似的 anonymousInstance 与 someInstance 的类型不同

  成员名称在匿名类型中必须是唯一的，并且可以从变量或其他对象成员名称中获取

    Dim anonymousInstance = New With {
        value1,
        value2,
        foo.value3
        '...
    }
    ' usage : anonymousInstance.value1 or anonymousInstance.value3
  

  每个成员都可以以 Key 关键字开头。那些成员将是 ReadOnly 属性，那些没有将是读/写属性

    Dim anonymousInstance = New With {
        Key value1,
        .Member2 = value2,
        Key .Member3 = value3
        '...
    }
  

  使用相同成员定义的两个匿名实例（名称，类型，Key 和 order 的存在）将具有相同的匿名类型。

    Dim anon1 = New With { Key .Value = 10 }
    Dim anon2 = New With { Key .Value = 20 }
  
    anon1.GetType Is anon2.GetType ' True
  

  匿名类型在结构上是等同的。具有至少一个具有相同 Key 值的 Key 属性的相同匿名类型的两个实例将是相等的。你必须使用 Equals 方法来测试它，使用 = 将无法编译，Is 将比较对象引用。

    Dim anon1 = New With { Key .Name = "Foo", Key .Age = 10, .Salary = 0 }
    Dim anon2 = New With { Key .Name = "Bar", Key .Age = 20, .Salary = 0 }
    Dim anon3 = New With { Key .Name = "Foo", Key .Age = 10, .Salary = 10000 }
  
    anon1.Equals(anon2) ' False
    anon1.Equals(anon3) ' True although non-Key Salary isn't the same
  

Named 和 Anonymous 类型的初始值设定项都可以嵌套和混合

    Dim anonymousInstance = New With {
        value,
        Key .someInstance = New SomeClass(argument) With {
            .Member1 = value1,
            .Member2 = value2
            '...
        }
        '...
    }