Can value or text be included in viewstate postback?

[Joel]

Great job Telerik on RadListBox.  We have a couple homegrown alternatives to this and have been hoping you would release this type of control so we could standardize.

One of our current projects relies on multiple combinations of controls created in runtime, after init.  To view these object and their values on postback, we are taking advantage of request.form in the postback and parsing the results.

 Dim str As String
 Dim str2 As String = ""
For Each str In Request.Form
   str2 += str & "  -  " & Request.Form(str) & "<br>"
Next

Response.Write(str2)

RadListbox gives us a method of tracing the users actions click by click, but it would be great if the postback could include either the text, or preferably the value, of the RadListboxItem along with the ordinal position changes.  We frequently need to randomize the position of the listitems in these situations to prevent bias so we will currently need to store additional data in hidden controls for the ordinal mapping.  I realize this is not standard usage of the control, but if you could add for future consideration either an ordered list of all values within Radlistbox in request.form (preferable), or include the value in the ordinal move data as it is now, it would streamline the process significantly.

The example beliw is the output of a 4 item list where the last item (3) is placed in position 0 recursively until the list is in it's original position again.

QUIHereType_ClientState - {"logEntries":[{"Type":5,"Index":"3","Data":{"NewIndex":"0"}},{"Type":5,"Index":"3","Data":{"NewIndex":"0"}},{"Type":5,"Index":"3","Data":{"NewIndex":"0"}},{"Type":5,"Index":"3","Data":{"NewIndex":"0"}}],"selectedIndices":[0],"checkedIndices":[],"scrollPosition":0}

Thanks again for your excellent work with this release.

-Joel

[edit]  subject line should not have included the word viewstate...

[Genady Sergeev]

Hi Joel,

In fact you can deserialize the client state in order to obtain the index of the items that have been logged. Once having their indexes, it is easy to obtain the text/value of a given item. Example code:

string rlbClientState = Request.Form["RadListBox1_ClientState"];
            JavaScriptSerializer serializer = new JavaScriptSerializer();
            RadListBoxClientState state = serializer.Deserialize<RadListBoxClientState>(rlbClientState);

            foreach (ClientStateLogEntry entry in state.LogEntries)
            {
                int index = int.Parse(entry.Index);
                string itemText = RadListBox1.Items[index].Text;
            }

Kind regards,
Genady Sergeev
the Telerik team

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[Joel]

Thank you for your reply.

I am not sure I will be able to use this since the listbox is created in runtime, after init, but I would like to try it as it will be applicable to future projects.  I am running into an error of unknown type "RadListBoxClientState".   Do I need to import something?

Imports System.Web.Script.Serialization

Partial Class Testing_ListBox
    Inherits System.Web.UI.Page

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        If IsPostBack Then
            Dim rlbClientState As String = Request.Form("RadListBox1_ClientState")
            Dim serializer As New JavaScriptSerializer()
            Dim state As RadListBoxClientState = serializer.Deserialize(Of RadListBoxClientState)(rlbClientState)

            For Each entry In state.LogEntries
                Dim index As IntegerInteger = Integer.Parse(entry.Index)
                Dim itemText As String = RadListBox1.Items(index).Text
                Response.Write(index & "-------" & itemText)
            Next
        End If
    End Sub
End Class

[Genady Sergeev]

Hi Joel,

Yes, I have forgotten to mention that you need to import the Telerik.Web namespace in order to use RadListBoxClientState class. The control being added after Init is not a problem, since it's addition is before PreRender. You only need to use Form.Controls instead of Page.Controls.

Best wishes,
Genady Sergeev
the Telerik team

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[Todd]

This worked perfectly for my situation.

We are dynamically adding RadListBox controls to a page, and upon postback I need via the Request.Form[] the value of the control, as the control is not accessible for some reason. Can't find it via FindControl() to save my life.

I am able to get the serialized value from this line:

string newValue = Request.Form[String.Format("ctl00_ctl00_ContentPlaceHolder1_ContentPlaceHolder1_NewInput_{0}actual_ClientState", newTermAF.ID.ToString())].ToString();

then using the JavaScriptSerializer I am able to get the newValue to a RadListBoxClientState object and get each value of each RadListBoxItem.

System.Web.Script.Serialization.JavaScriptSerializer serializer = new System.Web.Script.Serialization.JavaScriptSerializer();
RadListBoxClientState state = serializer.Deserialize<RadListBoxClientState>(newValue);
for (int i = 0; i < state.LogEntries.Length; i++)
{
     newValue = state.LogEntries[i].Data["value"].ToString();
     fieldTermsTable.Rows.Add(new string[2] { newTermAF.Name, newTermAFValue });
}

Thanks!