CODEWITHSUNDEEP
asp.net
felix Antony
felix Antony

Reputation: 1460

datalist created by callback events lost on postback

I bind datalist on callback event. on click of a button inside the datalist need a postback to fetch data for another datalist. but after postbacking, no datalist is visible on the page. I dont know whats happening on postback. Please help me for finding a solution....

 If IsPostBack = False Then
        callback = ClientScript.GetCallbackEventReference(Me, "message", "processMyResult", "context")
        Dim script As String = "function CallBack(message,context){" + callback + ";}"
        ClientScript.RegisterClientScriptBlock(Me.GetType(), "CB", script:=script, addScriptTags:=True)


        callbackhotelsearch = ClientScript.GetCallbackEventReference(Me, "message", "processhotelsearchResult", "context")
        Dim scriptsearch As String = "function callbackhotelsearch(message,context){" + callback + ";}"
        ClientScript.RegisterClientScriptBlock(Me.GetType(), "CB", script:=scriptsearch, addScriptTags:=True)

        SearchTextBox.Attributes.Add("onkeyup", "javascrpt:LookUpStock()")
        SearchTextBox.Attributes.Add("onfocus", "javascript:SetCursorToTextEnd()")
    End If





 Public Sub RaiseCallbackEvent(ByVal eventArgument As String) Implements System.Web.UI.ICallbackEventHandler.RaiseCallbackEvent

    If (eventArgument) Is Nothing Then

        returnValue = "-1"

    Else

        binddata(eventArgument)
    End If



    Dim sb As System.Text.StringBuilder = New System.Text.StringBuilder()
    Dim sw As System.IO.StringWriter = New System.IO.StringWriter(sb)
    Dim hw As HtmlTextWriter = New HtmlTextWriter(sw)
    dataListPackages.RenderControl(hw)
    returnValue = sb.ToString()

End Sub

Public Function GetCallbackResult() _
As String Implements _
System.Web.UI.ICallbackEventHandler.GetCallbackResult

    Return returnValue

End Function

Public Function binddata(ByVal eventArgument As String) As Nullable
    Dim adp As New dsRegistrationTableAdapters.searchPackagesTableAdapter()
    Dim dt As New dsRegistration.searchPackagesDataTable()
    dt = adp.GetData(eventArgument, StartDateTextBox.Text, EndDateTextBox.Text)
    'StartDateTextBox.Text = "11-12-2012"

    dataListPackages.DataSource = dt
    dataListPackages.DataBind()
    SearchTextBox.Focus()
    Return Nothing
End Function

thank you

Upvotes: 0

Views: 445

Answers (1)

Microsoft DN
Microsoft DN

Reputation: 10030

Data source items are not accessible after initial loading. They are available on databound only.

In your case, you can use HiddenField to store the Ids during post and then fetch data by that ID instead of dataitem because dataitem wont be available after postback.

Upvotes: 1

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