修改ObjectDataSource删除参数时出现问题

问题描述

| 我试图将参数添加到ObjectDataSource的删除事件中，如以下示例中的msdn。我为ObjectDataSource的deleteing事件生成了一个事件处理程序，它具有与示例中相同的签名，但是，当我尝试清除示例中的paramsFromPage时，收到一条错误消息，指出paramsFromPage是只读的。我需要在其他地方进行更改吗？ 此示例来自以下msdn页面： http://msdn.microsoft.com/zh-cn/library/system.web.ui.webcontrols.objectdatasource.deleting%28v=VS.90%29.aspx

Private Sub northwindEmployeeDeleting(ByVal source As Object,ByVal e As ObjectDataSourceMethodEventArgs)

    \' The GridView passes the ID of the employee
    \' to be deleted. However,the business object,EmployeeLogic,\' requires a northwindEmployee parameter,named \"ne\". Create
    \' it Now and add it to the parameters collection.
    Dim paramsFromPage As IDictionary = e.InputParameters

    If Not paramsFromPage(\"EmpID\") Is nothing Then

        Dim ne As New northwindEmployee(paramsFromPage(\"EmpID\").ToString())
        \' Remove the old EmpID parameter.
        paramsFromPage.Clear()
        paramsFromPage.Add(\"ne\",ne)


    End If
End Sub \' northwindEmployeeDeleting

编辑： 以下是我的代码

Protected Sub QueueDataSource_Deleting(ByVal sender As Object,ByVal e As ObjectDataSourceMethodEventArgs) Handles QueueDataSource.Deleting
    Dim paramsFromPage As IDictionary = e.InputParameters
    Dim queue As New QueueData

    If Not paramsFromPage(\"QueueNamek__backingField\") Is nothing Then
        queue.QueueNamek__backingField = paramsFromPage(\"QueueNamek__backingField\")
    End If

    If Not paramsFromPage(\"ServerNamek__backingField\") Is nothing Then
        queue.ServerNamek__backingField = paramsFromPage(\"ServerNamek__backingField\")
    End If

    paramsFromPage.Add(\"queue\",queue)
End Sub

尝试添加到有序字典时，抛出错误“ OrderedDictionary是只读的，无法修改。”。     

解决方法

对于Microsoft建议的解决方案，我找到了一个很好的解决方法。我发现，虽然不能以编程方式添加或删除参数，但可以声明性地添加它们，并且delete函数所需的参数会自动添加。同样，可以在删除事件中以编程方式修改集合中的参数。 这是我的解决方案：

\' Store the index of the row being deleted
Protected Sub QueueGrid_RowDeleting(ByVal sender As Object,ByVal e As System.Web.UI.WebControls.GridViewDeleteEventArgs) Handles QueueGrid.RowDeleting
    rowChosen = e.RowIndex
End Sub

\' Prepare parameter to be sent to deleting function
Protected Sub QueueDataSource_Deleting(ByVal sender As Object,ByVal e As System.Web.UI.WebControls.ObjectDataSourceMethodEventArgs) Handles QueueDataSource.Deleting
    Dim queue As QueueData = e.InputParameters(\"queue\")

    With queue
        .QueueNamek__BackingField = QueueGrid.Rows(rowChosen).Cells(2).Text
        .ServerNamek__BackingField = QueueGrid.Rows(rowChosen).Cells(3).Text
    End With
End Sub

我只是想知道是否有更好的方法从单元格中获取数据，以便更改列顺序不会破坏此代码。