Dynamically added DataGrid Columns and SortExpression

[Glenn Rosenthal]

I have a Web page with a datagrid for display search results. The first column contains a check box and a hidden field, and are defined with the datagrid.

                 <asp:DataGrid runat="server" ID="dgPaused" AutoGenerateColumns="false" AllowPaging="false" AllowSorting="true" cellspacing="0" cellpadding="3" rules="all" border="1" style="border-collapse:collapse;" OnItemDataBound="dgPaused_ItemDataBound" OnSortCommand="dgPaused_SortCommand" >
                    <HeaderStyle CssClass="FixedDataGridHeader" />
                    <ItemStyle />
 
                    <Columns>
                        <asp:TemplateColumn SortExpression="XXX" HeaderText="XXX">
                            <ItemTemplate>
                                <asp:CheckBox runat="server" ID="chkUnpause" />
                                <asp:HiddenField runat="server" ID="txtID" Value='<%# DataBinder.Eval(Container.DataItem, "BPID Reference")%>' />
                            </ItemTemplate>
                        </asp:TemplateColumn>
                    </Columns>
                </asp:DataGrid>                  
 
The remaining fields are added dynamically:
 
            // Build the header row.
            for (int i = 0; i < oDataSet.Tables[0].Columns.Count; i++)
            {
                string sColumnName = oDataSet.Tables[0].Columns[i].ColumnName;
                if (sColumnName != "BPID Reference")
                {
                    BoundColumn oNewColumn = new BoundColumn();
                    oNewColumn.HeaderText = sColumnName;
                    oNewColumn.DataField = sColumnName;
                    oNewColumn.SortExpression = sColumnName;
 
                    if (sColumnName == "Last Modified" || sColumnName == "Pending Time")
                        oNewColumn.DataFormatString = "{0: HH:mm M/d/yyyy}";
                    else
                        oNewColumn.DataFormatString = "{0}";
 
                    dgPaused.Columns.Add(oNewColumn);
                }
            }
 

Now, please note that sorting is enabled, and clicking on the header field should execute the function “dgPaused_SortCommand”. Why is it that only the original column, “XXX” actually executes the function? Clicking on any other header just returns to “Page_Load”.

I believe I am writing the code exactly as every example I have found.