Element 'Grid DropDownColumn' is not a known element

[Betty]

I am building a Grid using the Q1 2010 RadGrid control, and
using Template Form Update as my guide.

I have a Template edit form, and I'm having an issue when
trying to add a Telerik Grid Dropdown Column.
I am getting an error saying that the Grid Dropdown
Column is not a known element.

Below is a copy of my edit form template:

<telerik:RadGrid ID="RadGrid1" runat="server" CssClass="RadGrid" GridLines="None"
    AllowPaging="True" PageSize="20" AllowSorting="True" AutoGenerateColumns="False"
    ShowStatusBar="true" AllowAutomaticDeletes="True" AllowAutomaticInserts="True"
    AllowAutomaticUpdates="True" DataSourceID="SqlDataSource1" OnItemDeleted="RadGrid1_ItemDeleted"
    OnItemInserted="RadGrid1_ItemInserted" OnItemUpdated="RadGrid1_ItemUpdated" OnItemCommand="RadGrid1_ItemCommand"
    >
 <MasterTableView CommandItemDisplay="TopAndBottom" DataSourceID="SqlDataSource1" DataKeyNames="MCCLoadId">
    <Columns>
        <telerik:GridEditCommandColumn>
        </telerik:GridEditCommandColumn>
        <telerik:GridBoundColumn UniqueName="MCCNo" HeaderText="MCCNo" DataField="MCCNo">
            <HeaderStyle ForeColor="Silver" ></HeaderStyle>
            <ItemStyle ForeColor="Gray" />
        </telerik:GridBoundColumn>
        <telerik:GridBoundColumn DataField="MCC_Cmpt" HeaderText="MCC Compartment" UniqueName="MCC_Cmpt">
        </telerik:GridBoundColumn>
        <telerik:GridBoundColumn DataField="DeviceType_DeviceTypeId" HeaderText="Device Type" UniqueName="DeviceTypeId" >
        </telerik:GridBoundColumn>
    </Columns>
    <EditFormSettings EditFormType="Template">
        <FormTemplate>
            <table id="Table2" cellspacing="2" cellpadding="1" width="100%" border="0" rules="none"
               style="border-collapse: collapse; background: white;">
               <tr class="EditFormHeader">
                   <td colspan="2" style="font-size:small">
                        <b>MCC Load Details</b>
                   </td>
               </tr>
               <tr>
                   <td>
                        <table id="Table3" cellspacing="1" cellpadding="1" width="250" border="0" class="module">
                            <tr>
                                <td>
                                </td>
                                <td>
                                </td>
                            </tr>
                            <tr>
                                <td>
                                    MCC #:
                                </td>
                                <td>
                                    <asp:TextBox ID="TextBox1" runat="server" Text='<%# Bind("MCCNo") %>'></asp:TextBox>
                                </td>
                            </tr>
                            <tr>
                                <td>
                                    MCC Section:
                                </td>
                                <td>
                                    <asp:TextBox ID="TextBox2" runat="server" Text='<%# Bind("MCC_Sect") %>'></asp:TextBox>
                                </td>
                            </tr>
                            <tr>
                                <td>
                                    MCC Section Suffix:
                                </td>
                                <td>
                                    <asp:TextBox ID="TextBox3" runat="server" Text='<%# Bind("MCC_Sect_Suffix") %>'></asp:TextBox>
                                </td>
                            </tr>
                            <tr>
                                <td>
                                    MCC Compartment:
                                </td>
                                <td>
                                    <asp:TextBox ID="TextBox4" runat="server" Text='<%# Bind("MCC_Cmpt") %>'></asp:TextBox>
                                </td>
                            </tr>
                            <tr>
                                <td>
                                    MCC Compartment Suffix:
                                </td>
                                <td>
                                    <asp:TextBox ID="TextBox5" runat="server" Text='<%# Bind("MCC_Cmpt_Suffix") %>'></asp:TextBox>
                                </td>
                            </tr>
                            <tr>
                                <td>
                                    MCC Compartment Space Factor:
                                </td>
                                <td>
                                    <asp:TextBox ID="TextBox6" runat="server" Text='<%# Bind("MCC_Cmpt_Space_Factor") %>'></asp:TextBox>
                                </td>
                            </tr>
                            <tr>
                                <td>
                                    MCC Compartment Connection:
                                </td>
                                <td>
                                    <asp:TextBox ID="TextBox7" runat="server" Text='<%# Bind("MCC_Cmpt_Conn") %>'></asp:TextBox>
                                </td>
                            </tr>
                            <tr>
                                <td>
                                    MCC Short Circuit:
                                </td>
                                <td>
                                    <asp:TextBox ID="TextBox8" runat="server" Text='<%# Bind("MCC_Short_Ckt_Prot") %>'></asp:TextBox>
                                </td>
                            </tr>
                            <tr>
                                <td>
                                    MCC Short Circuit Rating:
                                </td>
                                <td>
                                    <asp:TextBox ID="TextBox9" runat="server" Text='<%# Bind("MCC_Short_Ckt_Rating") %>'></asp:TextBox>
                                </td>
                            </tr>
                            <tr>
                                <td>
                                    MCC Short Circuit Class:
                                </td>
                                <td>
                                    <asp:TextBox ID="TextBox10" runat="server" Text='<%# Bind("MCC_Short_Ckt_Class") %>'></asp:TextBox>
                                </td>
                            </tr>
                            <tr>
                                <td>
                                    MCC Control Device:
                                </td>
                                <td>
                                    <telerik:GridDropDownColumn DataField="DeviceType_DeviceTypeId" DataSourceID="SqlDataSource2"
                                        HeaderText="DeviceTypes" ListTextField="DeviceTypeName" ListValueField="DeviceTypeId"
                                        UniqueName="DeviceTypeId" ColumnEditorID="GridDropDownColumnEditor1">
                                    </telerik:GridDropDownColumn>
                                </td>
                            </tr>
                        </table>
                   </td>
               </tr>
        </FormTemplate>
    </EditFormSettings>
 </MasterTableView>
</telerik:RadGrid>

Thanks,
Jason

[Jayesh Goyani]

Hello betty,

Incorrect code

<telerik:GridDropDownColumn DataField="DeviceType_DeviceTypeId" DataSourceID="SqlDataSource2"
                                        HeaderText="DeviceTypes" ListTextField="DeviceTypeName" ListValueField="DeviceTypeId"
                                        UniqueName="DeviceTypeId" ColumnEditorID="GridDropDownColumnEditor1">
                                    </telerik:GridDropDownColumn>

Correct code

<asp:DropDownList ID="ddlTOC" runat="server" SelectedValue='<%# Bind("TitleOfCourtesy") %>'
                                                DataSource='<%# (new string[] { "Dr.", "Mr.", "Mrs.", "Ms." }) %>' TabIndex="7"
                                                AppendDataBoundItems="True">
                                                <asp:ListItem Selected="True" Text="Select" Value=""></asp:ListItem>
                                            </asp:DropDownList>

OR

<telerik:RadComboBox ID="ddlTOC" runat="server" SelectedValue='<%# Bind("TitleOfCourtesy") %>'
                                                DataSource='<%# (new string[] { "Dr.", "Mr.", "Mrs.", "Ms." }) %>' TabIndex="7"
                                                AppendDataBoundItems="True">
                                                <asp:ListItem Selected="True" Text="Select" Value=""></asp:ListItem>
                                            </telerik:RadComboBox>

Note : you can able to use "telerik:GridDropDownColumn" only in inside  tag <Columns>........<Columns> in Radgrid.
for more information please check below link.
Grid / Column Types

Thanks,
Jayesh Goyani

[Betty]

If I run the following example, I get the unknown element error for asp:ListItem

<telerik:RadComboBox ID="ddlTOC" runat="server" SelectedValue='<%# Bind("MCC_Ctrl_Device") %>'
             DataSource='<%# (new string[] { "Dr.", "Mr.", "Mrs.", "Ms." }) %>' TabIndex="7"
             AppendDataBoundItems="True">
      <asp:ListItem Selected="True" Text="Select" Value=""></asp:ListItem>
</telerik:RadComboBox>

I can use the other example with no problems.

I would like to utilize the Telerik controls to keep the themes consistent between all of the other controls on the page.

[Shinu]

Hello Betty,

You can add Items in ComboBox as shown below.
aspx:

<telerik:RadComboBox ID="ddlTOC" runat="server" SelectedValue='<%# Bind("CategoryID") %>' DataSource='<%# (new string[] { "Dr.", "Mr.", "Mrs.", "Ms." }) %>' TabIndex="7" AppendDataBoundItems="True">
  <Items>
    <telerik:RadComboBoxItem Selected="true" Text="select" Value="" />
  </Items>
</telerik:RadComboBox>

Thanks,
Shinu.