根据 DataReader 数据填充对象数组

发布于 2024-09-07 21:33:07 字数 716 浏览 0 评论 0原文

我不确定如何正确表达我的问题，但我想实现这样的目标。

我有一个名为 Products 的类，

public class Products

private ID as Integer

private Name as String

Public Property ProductID()
  Get
    Return ID
  End Get
  Set(ByVal value)
    ID = value
  End Set
End Property

在我的一个代码隐藏页面中，我从 SQL 命令检索数据并将其放入 datareader 对象中。

我如何才能声明该类，以便数据读取器中的每一行实际上都是该类的实例？

例如：

Dim myProduct() as New Product
Dim intCnt as Integer 

While datareaderData.read()
  intCnt += 1
  myProduct(intCnt) = new Product
  myProduct(intCnt).ID = datareaderData("ID")
  myProduct(intCnt).Name = datareaderData("Name")
End While

当我执行相同操作时，我收到错误“对象引用未设置为对象的实例”。

我对此感到非常困惑。非常感谢任何提示。谢谢。

原文

I am not sure how to phrase my question properly but I want to achieve something like this.

I have a class named Products

public class Products

private ID as Integer

private Name as String

Public Property ProductID()
  Get
    Return ID
  End Get
  Set(ByVal value)
    ID = value
  End Set
End Property

In one of my code behind pages, I am retrieving data from an SQL Command and placing the same into a datareader object.

How would I be able to declare the class so that each row in my datareader would actually be an instance of the said class?

Like for example:

Dim myProduct() as New Product
Dim intCnt as Integer 

While datareaderData.read()
  intCnt += 1
  myProduct(intCnt) = new Product
  myProduct(intCnt).ID = datareaderData("ID")
  myProduct(intCnt).Name = datareaderData("Name")
End While

When I do the same, I am getting an error "Object Reference Not Set to an Instance of an Object.

I am quite stumped on this one. Any tips greatly appreciated. Thanks.

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迷荒 2024-09-14 21:33:07

您应该使用 Arraylist 或 - 更好 - 通用列表（产品）。
此外，我强烈建议设置选项严格打开在项目的编译器设置中。

Dim products As New List(Of Product)
While datareaderData.read()
    Dim nextProduct As New Product
    nextProduct.ProductID = CType(datareaderData("ID"), System.Int32)
    nextProduct.Name = datareaderData("Name").ToString
    products.add(nextProduct)
End While

You should use an Arraylist or -better- a generic List(of Product).
Besides i would strongly recommend to set Option Strict On in your project's Compiler Settings.

Dim products As New List(Of Product)
While datareaderData.read()
    Dim nextProduct As New Product
    nextProduct.ProductID = CType(datareaderData("ID"), System.Int32)
    nextProduct.Name = datareaderData("Name").ToString
    products.add(nextProduct)
End While

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