combobox's loading twice

2 posts, 0 answers
  1. Byzza
    Byzza avatar
    8 posts
    Member since:
    Jul 2007

    Posted 28 Mar 2011 Link to this post

    ok, so I have 4 combo boxes bound to SQL Data sources which are meant to load based on the value of a 5th combo box.  Under normal postback conditions this works fine without any issues.

    I start to run into problems though when I programattically set the value of the 5th Combo Box on load.  When this happens the other 4 combos are loading their datasets twice, and with 3 of them having AppendDataitems="True" i end up with duplicates.

    Any help would be greatly appreciated.
    Thank you

    ASP.NET Code Example rcbcsType=Combo 5, rcbType2 is one of the other 4

      <telerik:RadComboBox ID="rcbcsType" runat="server" AppendDataBoundItems="true" AutoPostBack="true"
                        DataSourceID="sdsConfig" DataTextField="csTypeName" DataValueField="csType">
                            <telerik:RadComboBoxItem runat="server" Text="" Value="" />
                            <telerik:RadComboBoxItem runat="server" Text="All" Value="-1" />
    <asp:SqlDataSource ID="sdsConfig" runat="server" SelectCommand="SELECT csType, csTypeName FROM tblConfig"
            ConnectionString="<%$ ConnectionStrings:csBIR %>"></asp:SqlDataSource>
     <telerik:RadComboBox ID="rcbType2" runat="server" MarkFirstMatch="true" AppendDataBoundItems="true"
                        DataSourceID="sdsType2" DataTextField="Code" DataValueField="Code" Skin="Default">
                                <telerik:RadComboBoxItem Value="" Text="" />
        <asp:SqlDataSource ID="sdsType2" runat="server" ConnectionString="<%$ ConnectionStrings:csBIR %>"
            SelectCommand="SELECT '' as code, '' as codeType UNION SELECT [Code], [CodeType] FROM [rCodes] WHERE (([active] = 1) AND [CodeType] = 'ComplaintType' AND ([Type1] = @Type1)) Order By Code">
                <asp:ControlParameter Name="Type1" ControlID="rcbcsType" Type="String" />

    VB.NET Code Example

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
            Dim cstype As String = Request.QueryString("type")
            If Not Page.IsPostBack Then
                If csType <> "" Then
                    gblcsType = csType.ToUpper
                End If
            End If
    End Sub
    Protected Sub rcbcsType_DataBound(ByVal sender As Object, ByVal e As System.EventArgs) Handles rcbcsType.DataBound
            If Not Page.IsPostBack Then
                If gblcsType <> "" Then
                    Me.rcbcsType.SelectedValue = gblcsType 
                    Me.rcbcsType.Enabled = False
                End If
            End If
        End Sub
  2. Dimitar Terziev
    Dimitar Terziev avatar
    1268 posts

    Posted 01 Apr 2011 Link to this post


    Once you preselect a value from the "rcbcsType" combobox, the OnDataBound event of the "rcbcsType" combobox is fired twice.
    That's why you end up with data duplication.
    Since this issue appears only when you have such a custom scenario, we should use some validation in order to workaround it.

    My suggestion is to use a boolean variable which will indicate whether an item has been preselected .
    If an item has been preselected, when the OnDataBound event of the "rcbcsType" combobox  is fired for the first time, to clear the items from the second "rcbType2" , which have just been added.
    Thus you will have only the items added when the event is fired for the second time.

    All the best,
    Dimitar Terziev
    the Telerik team
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