修改ObjectDataSource删除参数时出现问题

Question

我正在尝试向 ObjectDataSource 的删除事件添加一个参数，如下面来自 msdn 的示例所示。我为 ObjectDataSource 的删除事件生成了一个事件处理程序，并且它具有与示例中相同的签名，但是，当我尝试像示例中那样清除 paramsFromPage 时，我收到一条错误，指出 paramsFromPage 是只读的。我需要在其他地方改变什么吗？

此示例来自以下 msdn 页面：

http://msdn.microsoft.com/en-us/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

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

Answer 1

我找到了 Microsoft 建议的解决方案的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，但可以以声明方式添加它们，并且会自动添加删除功能所需的参数。此外，可以在删除事件内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。