How to add textbox to telerik grid view

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C#

Here my code

  <telerik:RadGrid ID="gdComponent" AutoGenerateColumns="false"  runat="server"

MasterTableView-DataKeyNames="InqCompDetailId" PagerStyle-AlwaysVisible="true" GridLines="Vertical">
<MasterTableView>
<Columns>
<telerik:GridBoundColumn DataField="InqCompDetailId" Visible="false" HeaderText=""

SortExpression="InqCompDetailId" UniqueName="InqCompDetailId">
<HeaderStyle Width="5%" HorizontalAlign="Left" />
</telerik:GridBoundColumn>
<telerik:GridBoundColumn DataField="ItemName" HeaderText="Item Name"

SortExpression="ItemName" UniqueName="ItemName">
<HeaderStyle Width="5%" HorizontalAlign="Left" />
</telerik:GridBoundColumn>
<telerik:GridTemplateColumn ItemStyle-Width="5%">
<HeaderTemplate>Knit min per comp</HeaderTemplate>
<ItemTemplate>
<asp:TextBox ID="txtMinPerCom" Height="25px" CommandName="View" runat="server" AutoCompleteType="None" Text='' ClientIDMode="Static" CssClass="form-control" Font-Size="Smaller"></asp:TextBox>
</ItemTemplate>
</telerik:GridTemplateColumn>

If i remove txtMinPerCom gridview works well. If I add this Textbox my grid headers are missing and all data comes in one row. Please help

What I have tried:

add textbox to telerik grid