Ниже приведен пример как внедрить в DataGrid RadioButton контрол.

<%@ Page %>
<script runat="server" language="c#"> 

  string _current = "";
  void Page_Load(object sender, EventArgs e) {
    if (IsPostBack) _current = "," + Request.Form["uid"].ToString() + ",";
    _grid.DataSource = new int[] {1,2,3,4,5,6,7,8,9,10};
    _grid.DataBind();
  }
  
  void OnSaveButtonClick(object sender, EventArgs e) {
    Response.Write(Request.Form["uid"]);
  }
  
  string IsChecked(int id) {
    if(_current.IndexOf("," + id.ToString() + ",") >= 0) {
      return "checked";
    } else {
      return "";
    }
  }
</script>

<form runat="server">
  <asp:DataGrid runat="server" id="_grid">
    <Columns>
      <asp:TemplateColumn>
        <ItemTemplate>
          <input <%#IsChecked((int) DataBinder.Eval(Container, "DataItem"))%> type="radio" name="uid" value='<%# DataBinder.Eval(Container, "DataItem")%>'> 
        </ItemTemplate>
      </asp:TemplateColumn>
      <asp:TemplateColumn>
        <ItemTemplate>
          Item <%# DataBinder.Eval(Container, "DataItem")%>
        </ItemTemplate>
      </asp:TemplateColumn>
    </Columns>
  </asp:DataGrid>
  
  <asp:Button runat="server" Text="Save" Width="100px" onclick="OnSaveButtonClick"/>
</form>