将 DataReader 的结果存储到 VB.NET 中的数组中 [英] Storing results of a DataReader into an array in VB.NET

问题描述

如何存储 DataReader 到一个数组，但仍然能够通过列名引用它们?我基本上希望能够克隆 DataReader 的内容，以便我可以关闭阅读器并仍然可以访问.我不想将项目存储在 DataTable 就像大家建议的那样.

How can I store the results of a DataReader into an array, but still be able to reference them by column name? I essentially want to be able to clone the DataReader's content so that I can close the reader and still have access. I don't want to store the items in a DataTable like everyone suggests.

我看过很多答案，但我真的找不到我想要的答案

I've seen a lot of answers, but I couldn't really find any for what I wanted

推荐答案

我发现最简单的方法是用字典填充数组，以字符串为键，以对象为值，如下所示:

The easiest way I've found to do this is by populating the array with dictionaries with Strings as keys and Objects as values, like so:

' Read data from database
Dim result As New ArrayList()
Dr = myCommand.ExecuteReader()

' Add each entry to array list
While Dr.Read()
    ' Insert each column into a dictionary
    Dim dict As New Dictionary(Of String, Object)
    For count As Integer = 0 To (Dr.FieldCount - 1)
        dict.Add(Dr.GetName(count), Dr(count))
    Next

    ' Add the dictionary to the ArrayList
    result.Add(dict)
End While
Dr.Close()

所以，现在你可以像这样使用 for 循环遍历结果:

So, now you could loop through result with a for loop like this:

For Each dat As Dictionary(Of String, Object) In result
     Console.Write(dat("ColName"))
Next

非常类似于如果它只是 DataReader:

Quite similar to how you would do it if it were just the DataReader:

While Dr.Read()
    Console.Write(Dr("ColName"))
End While

这个例子使用的是 MySQL/NET 驱动程序，但同样的方法也可以用于其他流行的数据库连接器.

This example is using the MySQL/NET driver, but the same method can be used with the other popular database connectors.

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