DetailsView in ASP.Net - How to add another column on the side/add a control in each row?

Question

I have a DetailsView control on my page used to edit various fields of a record, which works well in this respect.

I am looking for a way to add one column (and if that works, why not more) to the right, which will be absolutely read-only, to show the same fields of another record for comparison purposes.

I am aware there is no obvious way to do such thing out of the box with DetailsView. I have looked into other controls (transposed GridView, someone recommended FormView, ListView), but nothing satisfies. I have some very special data binding setup using the DetailsView and I can't get out of it without losing some features.

Anyone on how to "hack in" additional columns (for display only) on a DetailsView ?

Answer 1

The solution I have now, is to use a second DetailsView, with Visible set to False in my aspx. In the code, I make sure to DataBind the hidden DetailsView that hosts the data for my third column first, then the initial DetailsView named ItemDetails.

And in the item created event, I pass to a third column the html rendering of my hidden controls (in the last code block) :

protected void ItemDetails_ItemCreated(object sender, EventArgs e)
        {
            if (dataItem2 != null) //compare enabled
            {
                var headerRow = ((DetailsView)sender).HeaderRow;
                var headerL = new Label();
                headerL.Text = header2;
                headerL.Style.Add("font-weight", "bold");
                var headerCell = new TableCell();
                headerCell.Controls.Add(headerL);
                headerCell.Style.Add("text-align", "right");
                headerRow.Cells.Add(headerCell);
                if (string.IsNullOrEmpty(header1) && string.IsNullOrEmpty(header2)) ((DetailsView)sender).HeaderRow.Visible = false;
            }
            else
            {
                ((DetailsView)sender).HeaderRow.Visible = false;
            }
            foreach (DetailsViewRow r in ItemDetails.Rows)
            {
                if (r.RowType == DataControlRowType.DataRow)
                {
                    // Assume the first cell is a header cell        
                    var dataCell = (DataControlFieldCell)r.Cells[0];
                    string dataFieldName = null;
                    if (dataCell.ContainingField is CustomBoundField) dataFieldName = ((CustomBoundField)dataCell.ContainingField).GetDataFieldName();
                    else if (dataCell.ContainingField is BoundField) dataFieldName = ((BoundField)dataCell.ContainingField).DataField;
                    if (dataItem2 != null) //compare enabled
                    {
                        if (!string.IsNullOrEmpty(dataFieldName)) //it's a field, copy boundField from hidden DetailsView
                        {
                            var ct = new TableCell();
                            var text = new StringWriter();
                            var html = new HtmlTextWriter(text);
                            dict[dataFieldName].RenderControl(html);
                            ct.Text = text.ToString().Replace("<td>", String.Empty).Replace("</td>", String.Empty);
                            r.Cells.Add(ct);
                        }
                    }
                }
            } 
        }