Adding a child control to a DataGrid at runtime

[PMichaud]

I have a custom control that takes xml data in a certain format and outputs that data using a datagrid. Most of the information is just plain text, but some of it needs to be editable, so sometimes I need to add a control to a given DataColumn at runtime.

 
ICollection BuildGrid(string xml_string)
    {
        XmlDocument xml = new XmlDocument();
        DataTable dt = new DataTable();
        DataRow dr;
        int colCnt;
 
        xml.LoadXml(xml_string);
        GridColumns = GetGridColumns(xml);
 
        colCnt = GridColumns.Count;
        for (int i = 0; i < colCnt; i++)
            dt.Columns.Add(new DataColumn(GridColumns[i], typeof(string)));
 
        for (int i = 0, cnt = xml.FirstChild.ChildNodes.Count; i < cnt; i++)
        {
            dr = dt.NewRow();
            XmlNodeList lst = xml.FirstChild.ChildNodes[i].ChildNodes;
            if (lst.Count != colCnt)
            {
                throw new XmlException("XML not well-formed!");
            } 
            //Here is the important bit!
            for (int j = 0; j < colCnt; j++)
                dr[j] = lst[j];
            dt.Rows.Add(dr);
        }
 
        DataView dv = new DataView(dt);
        return dv;
    }

That's the code that takes the xml, converts it to an XML object, then creates the grid programatically. The loop marked with "here's the important bit" takes the string value lst[j], and assigns it to DataColumn dr[j] -- my question is, how could I write something like this:

for (int j = 0; j < colCnt; j++)
  if (lst[j].IsTextboxField())    
  {
    Textbox txt = new Textbox();
    txt.Text = lst[j];
   dr[j].Controls.Add(txt);
  }
  else
  {
    dr[j] = lst[j];
  }