从VB.Net中的SQL查询读取数据

Question

我需要从SQL查询中收集信息。 我使用SQL数据源控件，因为获取数据后将在网格视图中使用它。

我的查询如下所示：[包装以提高可读性]

SqlDataSource1.SelectCommand = "SELECT [index] AS idex, store_number AS snum, 
    store_name AS sname, store_username AS suser, store_password AS spass, 
    store_count AS scount 
    FROM Stores 
    WHERE store_name = '" & Session("storename") & "'"

很草率，但希望能满足我的需求。 我对变量了解得很少，应该意味着索引字段应该存储到名为idex的变量中？ 这个对吗？ 以后如何使用？

如何从列中获取变量，然后将其放入文本框等内容中，

Answer 1

该代码的基本结构如下。

打开连接。 最好使用Using结构来做。 创建命令（同样， Using结构）。 执行命令并获取值。

Dim idx As Integer ' the variable to hold your index

Using conn As SqlConnection = New SqlConnection("your connection string") ' put your connection string here or get it from a config file
    conn.Open()
    Dim commandText As String = "SELECT [index] AS idex, store_number AS snum, store_name AS sname, store_username AS suser, store_password AS spass, store_count AS scount FROM Stores WHERE store_name = @storename"
    Using command As SqlCommand = New SqlCommand(commandText, conn)
        command.Parameters.Add(New SqlParameter("@storename", SqlDbType.VarChar, 50)).Value = "store name" ' replace the store name and the length of the field

        Using reader As SqlDataReader = command.ExecuteReader
            If reader.Read Then
                idx = reader.GetInt32(0) ' the first column
            End If
        End Using
    End Using
End Using

---

要从配置文件获取连接字符串，请执行以下操作：

添加对System.Configuration.dll的引用

将连接字符串添加到您的配置文件中：

<connectionStrings>
    <add name="YourConnection" connectionString="Details"/>
</connectionStrings>

您可以从代码中获取连接字符串

 Dim connStr As String = System.Configuration.ConfigurationManager.ConnectionStrings("YourConnection").ConnectionString