将新项目添加到对象数组 [英] Add new item to Object Array

问题描述

我有一个对象数组，其中包含带有数组的对象.当我稍后尝试添加另一个对象时，出现错误提示

I have an object array containing objects with arrays. When i try to add another object later i get an error saying

'An exception of type 'System.MissingMemberException' occurred in     
 Microsoft.VisualBasic.dll but was not handled in user code
Additional information: Public member 'Add' on type 'Object()()' not found.'

这是我尝试添加新成员的方法

And here is how i try to add new member

Dim data As Object = {
                   New Object() {"Year", "Sales", "Expenses"},
                   New Object() {"2004", 1000, 400},
                   New Object() {"2005", 1170, 460},
                   New Object() {"2006", 660, 1120},
                   New Object() {"2007", 1030, 540}
              }

Dim newObj = New Object() {"2008", 1030, 540}
data.Add(newObj)  'here the error occures

我尝试将数据更改为 List(of Object) 然后它起作用了但是 List 的格式后来不可接受(我将数据作为 json 发送到不同的 api).

I tried changing data to List(of Object) and then it worked but the format of List is not acceptable later (i send data to different api as json).

可能这很简单，但我是新手 :) 提前感谢您的帮助.

Probably it's easy issue but i'am kind of newbie :) Thanks for help in advance.

推荐答案

变量 data 是一个 Object.Object 没有 Add 方法.但是由于您实际上将其声明为 Object()(对象数组)，因此您不能使用 Add ，因为数组具有固定大小.

The variable data is an Object. Object has no Add method. But since you actually declare it as Object()(an array of objects) you cannot use Add either because an array has a fixed size.

改为使用可以调整大小的List(Of Object):

Instead use a List(Of Object) which can be resized:

Dim data As List(Of Object) = New List(Of Object) From
{
       New Object() {"Year", "Sales", "Expenses"},
       New Object() {"2004", 1000, 400},
       New Object() {"2005", 1170, 460},
       New Object() {"2006", 660, 1120},
       New Object() {"2007", 1030, 540}
}
// ...
data.Add(newObj)  

但是，如果要存储字符串，为什么还要使用对象呢?我会将其声明为 List(Of String)，否则您总是需要将其拆箱到与装箱相同的类型，这样效率低下、可读性差且更容易出错.

However, why do you use objects at all if you want to store strings? I would declare it as List(Of String), otherwise you always need to unbox to the same type that was boxed which is inefficient, less readable and more error-prone.

如果您需要 Object()，您可以在完成后使用 data.ToArray().

If you need an Object() you can use data.ToArray() when you're finished with it.

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