ComboBox Not Clearing initial page load data when show more results is selected.

[Ryan]

On page load i bind data to the combobox control but if the user selects the ShowMoreResults arrow
 down button to load more items(even though i display all items) it appends the same amount of items
 to the box without clearing the original binded items. even though when the rcboSearch_ItemsRequested is launched it is set to clear the combobox and
indeed stepping through the code it says it has the output on screen is that
the page load data is mixed with the new data.

note if the user starts to type into the combobox the results get cleared.
the problem is only when i append data on page load and select ShowMoreResults
arrow which seems to be present even though there shouldnt be any more results to load,
 this triggers rcboSearch_ItemsRequested and adds the same amount of data
 as page load to the data already there

<telerik:RadComboBox runat="server" ID="ComboAllContacts"  Width="300"
                ShowMoreResultsBox="true" MaxLength="250" EnableVirtualScrolling="true" EnableLoadOnDemand="true"
                EmptyMessage="Select Area" MarkFirstMatch="false" AllowCustomText="false" HighlightTemplatedItems="false"
                EnableItemCaching="false" MinFilterLength="1" CssClass="fx-areaselector"  OnItemsRequested="rcboSearch_ItemsRequested"
                skin="Fluent" EnableEmbeddedSkins="false" DataValueField="CRMAreaID" ClientIDMode="Static" >

     <ItemTemplate>
           <div class="searchResult">
           <div class="profilePicContainer">
          <a  title="View <%# DataBinder.Eval(Container, "Attributes['Name']")%>"><%# DataBinder.Eval(Container,        "Attributes['Name']")%></a>
         </div>
         </div>
           <div class="separatorTemplate" style="display: none;">
            <h2><%#DataBinder.Eval(Container, "Attributes['Name']")%></h2>
           </div>
       </ItemTemplate>
</telerik:RadComboBox>

<<< Page Load >>>

If Not IsPostBack Then
            Dim currentRowType = String.Empty

            Dim ds As DataSet = AreaHelper.GetMyAreas()
            Dim dt As DataTable = ds.Tables(0)


            ComboAllContacts.DataValueField = "CRMAreaID"

            For Each row As DataRow In dt.Rows

                Dim item As New RadComboBoxItem
                Dim CRMAreaID As String = row("CRMAreaID").ToString()
                Dim Name As String = row("Name").ToString()
                Dim Region As String = row("Region").ToString()

                If currentRowType <> Region Then
                    ' Add separator Row
                    ComboAllContacts.Items.Add(CreateSeparatorItem(Region))
                    currentRowType = Region
                End If


                item.Value = CRMAreaID.ToString()
                item.Text = Name

                item.Attributes.Add("CRMAreaID", CRMAreaID)
                item.Attributes.Add("Region", Region)
                item.Attributes.Add("Name", Name)
                item.Attributes.Add("IsSeparator", False)
                item.Attributes.Add("onclick", "NavigateAreaSelection(" + CRMAreaID + ")")

                If Not String.IsNullOrWhiteSpace(item.Text) Then
                    ComboAllContacts.Items.Add(item)
                End If
            Next row


            ComboAllContacts.DataBind()

        End If

<<<ItemsRequested>>>

Protected Sub Protected Sub rcboSearch_ItemsRequested(ByVal sender As Object, ByVal e As RadComboBoxItemsRequestedEventArgs)

        '' RadComboBox combo = this.FindControl("combo") as RadComboBox;
        ComboAllContacts.ClearSelection()
        ComboAllContacts.Items.Clear()
        ComboAllContacts.Dispose()
        ComboAllContacts.Text = ""




        Dim data As DataTable = GetData(e.Text)

        Dim itemOffset As Integer = e.NumberOfItems
        Dim endOffset As Integer = data.Rows.Count ''Math.Min(itemOffset + ItemsPerRequest, data.Rows.Count)
        e.EndOfItems = endOffset = data.Rows.Count

        'If data.Rows.Count > 0 Then

        'End If

        Dim currentRowType = String.Empty


        ''For i As Integer = itemOffset To endOffset - 1
        For Each row As DataRow In data.Rows

            Dim item As New RadComboBoxItem
            'Dim CRMAreaID As String = data.Rows(i)("RowID").ToString()
            'Dim rowName As String = data.Rows(i)("Name").ToString()
            'Dim Region As String = data.Rows(i)("Region").ToString()

            Dim CRMAreaID As String = row("RowID").ToString()
            Dim rowName As String = row("Name").ToString()
            Dim Region As String = row("Region").ToString()

            If currentRowType <> Region Then
                ' Add separator Row
                ComboAllContacts.Items.Add(CreateSeparatorItem(Region))
                currentRowType = Region
            End If


            item.Value = CRMAreaID
            item.Text = rowName

            item.Attributes.Add("CRMAreaID", CRMAreaID)
            item.Attributes.Add("Region", Region)
            item.Attributes.Add("Name", rowName)
            item.Attributes.Add("IsSeparator", False)
            item.Attributes.Add("onclick", "NavigateAreaSelection(" + CRMAreaID + ")")

            If Not String.IsNullOrWhiteSpace(item.Text) Then
                ComboAllContacts.Items.Add(item)
            End If
            ''Next row
        Next



        If ComboAllContacts.Items.Count > 0 Then
            ComboAllContacts.DataBind()
        Else

        End If
        e.Message = GetStatusMessage(endOffset, ComboAllContacts.Items.Count)(ByVal sender As Object, ByVal e As RadComboBoxItemsRequestedEventArgs)

        '' RadComboBox combo = this.FindControl("combo") as RadComboBox;
        ComboAllContacts.ClearSelection()
        ComboAllContacts.Items.Clear()
        ComboAllContacts.Dispose()
        ComboAllContacts.Text = ""




        Dim data As DataTable = GetData(e.Text)

        Dim itemOffset As Integer = e.NumberOfItems
        Dim endOffset As Integer = data.Rows.Count ''Math.Min(itemOffset + ItemsPerRequest, data.Rows.Count)
        e.EndOfItems = endOffset = data.Rows.Count

        'If data.Rows.Count > 0 Then

        'End If

        Dim currentRowType = String.Empty


        ''For i As Integer = itemOffset To endOffset - 1
        For Each row As DataRow In data.Rows

            Dim item As New RadComboBoxItem
            'Dim CRMAreaID As String = data.Rows(i)("RowID").ToString()
            'Dim rowName As String = data.Rows(i)("Name").ToString()
            'Dim Region As String = data.Rows(i)("Region").ToString()

            Dim CRMAreaID As String = row("RowID").ToString()
            Dim rowName As String = row("Name").ToString()
            Dim Region As String = row("Region").ToString()

            If currentRowType <> Region Then
                ' Add separator Row
                ComboAllContacts.Items.Add(CreateSeparatorItem(Region))
                currentRowType = Region
            End If


            item.Value = CRMAreaID
            item.Text = rowName

            item.Attributes.Add("CRMAreaID", CRMAreaID)
            item.Attributes.Add("Region", Region)
            item.Attributes.Add("Name", rowName)
            item.Attributes.Add("IsSeparator", False)
            item.Attributes.Add("onclick", "NavigateAreaSelection(" + CRMAreaID + ")")

            If Not String.IsNullOrWhiteSpace(item.Text) Then
                ComboAllContacts.Items.Add(item)
            End If
            ''Next row
        Next



        If ComboAllContacts.Items.Count > 0 Then
            ComboAllContacts.DataBind()
        Else
        End If
        e.Message = GetStatusMessage(endOffset, ComboAllContacts.Items.Count)

[Nencho]

Hello Ryan,

As I can see, you had comment out the itemOffset calculation, on which the correct behavior of the desired functionality rely. The itemOffset and endOffset are responsible for calculating the portion of items, which is about to be loaded in the RadComboBox. Please refer to our online demo, where this functionality is implemented.

Greetings,
Nencho
the Telerik team