使用强类型DataSet更新ASP.Net/VB.Net数据库

Question

我们希望使用通过更改ASP.Net上的值获得的值来更新SQL Server 2012数据库中的数据DetailsView.我想使用更新数据库

• 一个强类型的DataSet调用 DataSetParentsDetails
• 一个叫做TableAdapter的 ParentsDetailsTableAdapter
• 一个名为的DataTable ParentsDetails.

这些是使用DataSet Designer创建的.

这是代码隐藏文件中的代码,用于计算我们要更新到数据库中的数量:

Protected Sub DetailsViewDetails_ItemCommand(sender As Object, e As System.Web.UI.WebControls.DetailsViewCommandEventArgs)
  Dim dcmAmountToAdjust As Decimal
  Dim StrSqlStatement As String

  Select Case e.CommandName
    Case "Add"
    Case "Edit"
      dcmOriginalRegistrationFee = GetValueFromLabelRegistrationFee()
    Case "Delete"
    Case "Update"
      dcmNewRegistrationFee = GetValueFromTextBoxRegistrationFee()
      dcmAmountToAdjust = dcmNewRegistrationFee - dcmOriginalRegistrationFee
      ' Update the tuition balance in the parent's data.
      '-------------------------------------------------
      StrSqlStatement =
        "Update Students " & _
        "Set RegistrationCode = RegistrationCode + @AmountToAdjust " & _
        "Where StudentID = @ID"
      ' Code to update the database goes here.
      '---------------------------------------
  End Select
End Sub

我确信之前曾多次询问过这个问题,但我找不到如何使用查询的好例子:StrSqlStatement通过强类型DataSet更新数据库.

Answer 1

首先,您需要一个连接字符串,最好将连接字符串存储在web.config文件中:

<connectionStrings>
  <add name="MyConnectionString" connectionString="Data Source=putYourServerAndInstanceNameHere;Initial Catalog=putYourDatabaseNameHere;User ID=putYourSqlUsernameHere;Password=password" providerName="System.Data.SqlClient" />
</connectionStrings>

这是根<configuration>元素的直接子元素.有关连接字符串的更多信息,请访问http://www.connectionstrings.com.

然后你需要在你的代码隐藏中进行一些导入,如果你还没有它们,你需要将它们作为项目的引用添加:

Import System.Data
Import System.Data.SqlClient

然后我们连接到数据库并运行我们的命令,我们使用参数因为它们更安全.

'build the connection object using the string from the web.config file
Using conn As New SqlConnection(ConfigurationManager.ConnectionStrings("MyConnectionString").ConnectionString)
  'build the command object specifying the command text and the connection to use, conn
  Using cmd As New SqlCommand("UPDATE Students SET RegistrationCode = RegistrationCode + @AmountToAdjust WHERE StudentID = @ID", conn)
    'add the parameters needed by the command
    cmd.Parameters.AddWithValue("@AmountToAdjust", amountToAdjust)
    cmd.Parameters.AddWithValue("@ID", studentID)
    'try to open the connection and execute the statement
    Try
      conn.Open()
      cmd.ExecuteNonQuery()
    Catch ex As Exception
      'handle the exception here
    End Try
  End Using
End Using

请注意,这里不需要使用conn.Close(),因为Using语句将为您处理(SqlConnection的Dispose方法在它仍处于打开状态时关闭连接).