Question

I have a standard ASP.NET GridView and I’d like the first column (a emplateField) to be rendered as <th>, or in ASP.NET terms, I’d like to set it to the GridView RowHeaderColumn property. But that property is looking for the name of a DataItem (from a BoundColumn).

How can I render my TemplateField with <th> tags?

Answer 1

Finally found a workaround for this. I am not sure if this code has anything to do with good ASP.NET practices, but it does the trick:

public class FirstColumnHeaderGridView : GridView
{
    protected override void InitializeRow(GridViewRow row, DataControlField[] fields)
    {
        DataControlFieldCell cell = new DataControlFieldHeaderCell(fields[0]);
        DataControlCellType header = DataControlCellType.DataCell;

        fields[0].InitializeCell(cell, header, row.RowState, row.RowIndex);
        row.Cells.Add(cell);


        DataControlField[] newFields = new DataControlField[fields.Length - 1];
        for (int i = 1; i < fields.Length; i++)
        {
            newFields[i - 1] = fields[i];
        }

        base.InitializeRow(row, newFields);
    }
}

Let me explain what is going on here. We are creating a special type of GridView, that will render its first column using <th> tags no matter how this column is created. For this we are overriding the InitializeRow method. This method basically configures cells for the row. We are handling the first cell, and let standard GridView take care of the rest.

The configuration we are applying to the cell is fully taken from the GridView implementation and is enough for the cell to be rendered with <th> tag instead of <td>.

After that workaround the usage is absolutely standard – register our class as a server control and use it as usual GridView:

<%@ Register Assembly="WebApplication1" Namespace="WebApplication1" TagPrefix="wa1" %>
...
<wa1:FirstColumnHeaderGridView ID="Grid1" runat="server" ...>
    <Columns>
        <asp:TemplateField>
            <ItemTemplate>
                Will be inside th
            </ItemTemplate>
        </asp:TemplateField>
        <asp:TemplateField>
            <ItemTemplate>
                Will be inside td
            </ItemTemplate>
        </asp:TemplateField>
    </Columns>
</wa1:FirstColumnHeaderGridView>