Telerik Forums / UI for ASP.NET AJAX Forum / ComboBox /

Multicolumn Radcombox insert a blank item

Telerik UI for ASP.NET AJAX
Resources Buy Try

5 posts, 0 answers

Calsh

15 posts

Member since:
Dec 2012

Posted 27 Oct 2013 Link to this post

Hi

Using a Multicolumn Combobox with OpenAccess and trying to insert a blank item - as need to
have the option of not selecting any item from the list - tried various solutions/posts with no success - code for combobox as below

<telerik:RadComboBox runat="server" ID="RadComboBox1" Height="190px" Width="100%"

    MarkFirstMatch="true" DataSourceID="OpenAccessLinqDataSource1" EnableLoadOnDemand="true"

    HighlightTemplatedItems="true" DataValueField="PartID" DataTextField="PartNumber"

    AppendDataBoundItems="True" SelectedValue='<%# Bind("PartID") %>' ItemsPerRequest="10"

    EnableVirtualScrolling="True" Filter="Contains" OnSelectedIndexChanged="RadComboBox1_SelectedIndexChanged"

    AutoPostBack="True">

    <HeaderTemplate>

        <ul>

            <li class="col1">Part Number</li>

            <li class="col2">Part Description</li>

        </ul>

    </HeaderTemplate>

    <ItemTemplate>

        <ul>

            <li class="col1">

                <%# DataBinder.Eval(Container.DataItem, "PartNumber")%>

            </li>

            <li class="col2">

                <%# DataBinder.Eval(Container.DataItem, "PartDescription")%></li>

        </ul>

    </ItemTemplate>

</telerik:RadComboBox>

Tried online demo http://www.telerik.com/help/aspnet-ajax/combobox-insert-default-item-when-databinding.html

Thanks
Shinu

17764 posts

Member since:
Mar 2007

Posted 28 Oct 2013 Link to this post

Hi Calsh,

Please have a look into the complete code to insert a blank Item in RadMultiColumComboBox.

ASPX:

<telerik:RadComboBox runat="server" ID="RadComboBox1" Height="190px" Width="420px"

    AppendDataBoundItems="true" AutoPostBack="true" NoWrap="true">

    <HeaderTemplate>

        <ul>

            <li class="col1">City Name</li>

            <li class="col2">Country Name</li>

        </ul>

    </HeaderTemplate>

    <ItemTemplate>

        <ul>

            <li class="col1">

                <%# Container.DataItem != null ? DataBinder.Eval(Container.DataItem, "Cityname") : DataBinder.Eval(Container, "Text")%>

            </li>

            <li class="col2">

                <%# Container.DataItem != null ? DataBinder.Eval(Container.DataItem, "Cityname") : DataBinder.Eval(Container, "Text")%>

            </li>

        </ul>

    </ItemTemplate>

    <Items>

        <telerik:RadComboBoxItem Text="" />

    </Items>

</telerik:RadComboBox>

C#:

protected void Page_Load(object sender, EventArgs e)

{

    RadComboBox1.DataBind();

    String connstring = WebConfigurationManager.ConnectionStrings["NorthwindConnectionString"].ConnectionString;

    SqlConnection conn = new SqlConnection(connstring);

    SqlDataAdapter adapter = new SqlDataAdapter();

    adapter.SelectCommand = new SqlCommand("SELECT [Cityname], [Countryname] FROM [City]", conn);

    DataTable data = new DataTable();

    conn.Open();

    try

    {

        adapter.Fill(data);

    }

    finally

    {

        conn.Close();

    }

    RadComboBox1.DataSource = data;

    RadComboBox1.DataTextField = "Cityname";

    RadComboBox1.DataValueField = "Countryname";

    RadComboBox1.DataBind();

}

Hope this will helps you.
Thanks,
Shinu.
Calsh

15 posts

Member since:
Dec 2012

Posted 28 Oct 2013 Link to this post

I'm using VB - changed as below - which puts a blank item in the combobox - but get error ' is not a valid value for Int32' when 'update' record - the field being updated is int32 and allows nulls and acts as a lookup to another table

(Using OpenAccess with simple binding and edit form template to allow editing of record)

<li class="col1">

<%# If(Container.DataItem IsNot Nothing, DataBinder.Eval(Container.DataItem, "PartNumber"), DataBinder.Eval(Container, "Text"))%>

</li>

Thanks
Shinu

17764 posts

Member since:
Mar 2007

Posted 28 Oct 2013 Link to this post

Hi Calsh,

I guess your RadComboBox is inside another control.(Here for example inside RadGrid). I have tried a sample scenario and was able to update the data. Please have a look into the following code.
ASPX:

<telerik:RadGrid ID="RadGrid1" runat="server" DataSourceID="SqlDataSource1" AllowAutomaticUpdates="true">

    <MasterTableView DataSourceID="SqlDataSource1" AutoGenerateColumns="False" DataKeyNames="EmployeeID">

        <Columns>

            <telerik:GridEditCommandColumn>

            </telerik:GridEditCommandColumn>

            <telerik:GridBoundColumn DataField="EmployeeID" DataType="System.Int32" FilterControlAltText="Filter OrderID column"

                HeaderText="EmployeeID" SortExpression="EmployeeID" UniqueName="EmployeeID">

            </telerik:GridBoundColumn>

            <telerik:GridBoundColumn DataField="ReportsTo" FilterControlAltText="Filter CustomerID column"

                HeaderText="ReportsTo" SortExpression="ReportsTo" UniqueName="ReportsTo">

            </telerik:GridBoundColumn>

        </Columns>

        <EditFormSettings EditFormType="Template">

            <FormTemplate>

                <telerik:RadComboBox runat="server" ID="RadComboBox1" Height="190px" Width="420px"

                    AppendDataBoundItems="true" AutoPostBack="true" NoWrap="true" DataSourceID="SqlDataSource1"

                    DataTextField="EmployeeID" DataValueField="EmployeeID">

                    <HeaderTemplate>

                        <ul>

                            <li class="col1">EmployeeID</li>

                            <li class="col2">ReportsTo</li>

                        </ul>

                    </HeaderTemplate>

                    <ItemTemplate>

                        <ul>

                            <li class="col1">

                                <%# Container.DataItem != null ? DataBinder.Eval(Container.DataItem, "EmployeeID") : DataBinder.Eval(Container, "Text")%>

                            </li>

                            <li class="col2">

                                <%# Container.DataItem != null ? DataBinder.Eval(Container.DataItem, "ReportsTo") : DataBinder.Eval(Container, "Text")%>

                            </li>

                        </ul>

                    </ItemTemplate>

                    <Items>

                        <telerik:RadComboBoxItem Text="" />

                    </Items>

                </telerik:RadComboBox>

                <asp:Button ID="btnUpdate" Text="Update" runat="server" CommandName="Update"></asp:Button>

            </FormTemplate>

        </EditFormSettings>

    </MasterTableView>

</telerik:RadGrid>

<asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:NorthwindConnectionString %>"

    SelectCommand="SELECT top 5 [EmployeeID], [LastName],[ReportsTo] FROM [EmployeeDetails]"

    UpdateCommand="UPDATE [EmployeeDetails] SET [ReportsTo] = @ReportsTo WHERE [EmployeeID] = @EmployeeID">

    <UpdateParameters>

        <asp:Parameter Name="ReportsTo" Type="Int32"></asp:Parameter>

        <asp:Parameter Name="EmployeeID" Type="Int32"></asp:Parameter>

    </UpdateParameters>

</asp:SqlDataSource>

Please make sure that your updating column allows null value to add into database table. For more help, please provide your complete code.

Thanks,
Shinu.
Calsh

15 posts

Member since:
Dec 2012

Posted 29 Oct 2013 Link to this post

Tried as you suggested - but still no luck - the database field that is being updated allows nulls

I'm using a GridDropDownColumn that is bound to a different data source than the RadGrid - got a solution by adding a blank item in the RadGrid_ItemDataBound Event as code below (removed other columns etc. to make it easier to read) - used this code to add a blank item to other dropdown lists (copied it but can't remember where found it) - the only disadvantage to this method is that the blank item appears at the bottom of the list - but otherwise works OK

<telerik:RadGrid runat="server" DataSourceID="OpenAccessLinqDataSourceItems"

    AllowAutomaticDeletes="True" AllowAutomaticInserts="True"

    AllowAutomaticUpdates="True" ID="RadGridItems" AutoGenerateColumns="False">

    <MasterTableView DataKeyNames="ItemID" DataSourceID="OpenAccessLinqDataSourceItems" EditMode="PopUp">

        <Columns>

            <telerik:GridDropDownColumn FilterControlAltText="Filter Part column" UniqueName="PartID"

                DataSourceID="OpenAccessLinqDataSourceParts" DataField="PartID" HeaderText="Part Number"

                SortExpression="PartID" ListValueField="PartID" AllowSorting="true" ListTextField="PartNumber"

                DropDownControlType="DropDownList">

            </telerik:GridDropDownColumn>

        </Columns>

        <EditFormSettings EditFormType="Template">

            <FormTemplate>

                <telerik:RadComboBox runat="server" ID="RadComboBox1"

            DataSourceID="OpenAccessLinqDataSourceParts" EnableLoadOnDemand="true"

                            DataValueField="PartID" DataTextField="PartNumber"

                            AppendDataBoundItems="True" SelectedValue='<%# Bind("PartID") %>'

                            AutoPostBack="True" >

                        <HeaderTemplate>

                            <ul>

                                    <li class="col1">Part Number</li>

                                        <li class="col2">Part Description</li>

                                </ul>

                        </HeaderTemplate>

                            <ItemTemplate>

                                <ul>

                                            <li class="col1">

                                                <%# DataBinder.Eval(Container.DataItem, "PartNumber")%>

                                            </li>

                                            <li class="col2">

                                                    <%# DataBinder.Eval(Container.DataItem, "PartDescription")%>

                                            </li>

                                    </ul>

                            </ItemTemplate>

                    </telerik:RadComboBox>

    </FormTemplate>

        </EditFormSettings>

    </MasterTableView>

</telerik:RadGrid>

Private Sub RadGridItems_ItemDataBound(ByVal sender As Object, ByVal e As Telerik.Web.UI.GridItemEventArgs) Handles RadGridItems.ItemDataBound

    If (TypeOf e.Item Is GridEditableItem AndAlso e.Item.IsInEditMode) Then

        Dim editItem As GridEditFormItem = DirectCast(e.Item, GridEditFormItem)

        comboBoxPartID = (TryCast(editItem.FindControl("RadComboBox1"), RadComboBox))

        selectedPartIDValue = comboBoxPartID.SelectedValue

        With comboBoxPartID

            .Items.Add(New RadComboBoxItem("", "0"))

            If selectedPartIDValue = " " Then

                .SelectedValue = CStr(0)

            Else

                .SelectedValue = selectedPartIDValue

            End If

        End With

    End If

End Sub

Multicolumn Radcombox insert a blank item

Calsh

Shinu

Calsh

Shinu

Calsh