How to display value of foreign key in GridView?

Question

In a Web Forms ASP.NET application I have a stored procedure that joins two tables as follows:

CREATE PROCEDURE dbo.usp_DepartmentsServiceChannelsSelect
AS
    SET NOCOUNT ON
SELECT     d.ID, d.Description,  s.ServiceChannel
FROM         Departments d
INNER JOIN [ServiceChannels] s
ON s.ID = d.ServiceChannel

GO

So the Departments get selected with ID, Description and a ServiceChannel that is connected to a department gets returned as well.

This stored procedure I use in a Typed Dataset with a TableAdapter called Department that has the method GetDepartmentsWithServiceChannels:

static public DepartmentDataTable GetDepartmentsWithServiceChannels()
{
    using (DepartmentTableAdapter departmentTA = new DepartmentTableAdapter())
    {
        return departmentTA.GetDepartmentsWithServiceChannels();
    }
}

This method I use in a view to bind a DepartmentCollection in the code-behind as follows:

    private void BindDepartmentsAfterSorting(string sortexpression, SortDirection 
              sortDirection)
    {
        DepartmentCollection deptCollection = 
              ServiceInterfaceRegistry.DepartmentManager.GetDepartments(false);

        if (deptCollection != null)
        {
            Common.Comparer<Department> objcmp = new Common.Comparer<Department>();
            objcmp.SortClasses.Add(new SortClass(sortexpression, sortDirection));
            deptCollection.Sort(objcmp);
        }
        MyGridView.DataSource = deptCollection;
        MyGridView.DataBind();
    }

Where MyGridvIew looks as follows:

<asp:GridView ID="MyGridView" runat="server" DataKeyNames="ID" AutoGenerateColumns="False" Width="1000px"
            AllowSorting="True" AllowPaging="True" EmptyDataText="Geen afdeling gevonden." OnRowDataBound="AfdelingGridView_RowDataBound" OnRowDeleting="AfdelingGridView_RowDeleting"  OnRowEditing="MyGridView_RowEditing" OnPageIndexChanging="AfdelingGridView_PageIndexChanging" OnSorting="AfdelingGridView_Sorting">
            <Columns>
                <asp:ButtonField ButtonType="Button" Text="Delete/edit" CommandName="Edit">
                    <ItemStyle Width="20px" />
                </asp:ButtonField>
                <asp:TemplateField Visible ="False">
                    <ItemTemplate>
                        <asp:Button ID="Delete" runat="server" CommandName="Delete"  
           Text="Verwijderen" Font-Bold="false" />
                        </ItemTemplate> 
                        <ItemStyle Width="20px" />  
                  </asp:TemplateField>
                <asp:BoundField DataField="Description" HeaderText="Description" ReadOnly="True" SortExpression="Description" />
                <asp:BoundField DataField="ServiceChannel" HeaderText="Service Channel" ReadOnly="True"  />

            </Columns>
            <HeaderStyle HorizontalAlign="Left" />
</asp:GridView>

Unfortunately, the return departmentTA.GetDepartmentsWithServiceChannels() part returns the following error:

Input string was not in a correct format.Couldn't store in ServiceChannel Column. Expected type is Int32.

How can I make the GridView do display the string value of the foreign key?

Answer 1

Solution was to make ServiceChannel object with ID property based on the datatable and match this object's ID in the GetDepartments method:

Department tmpDepartment = new Department(departmentRow);
            tmpDepartment.ServiceChannel = channels.Where(c => c.Id == 
                   departmentRow.ServiceChannelID).FirstOrDefault();

then this property can be accessed on the view via

e.Row.Cells[e.Row.Cells.Count - 1].Text = ((Department) 
                               e.Row.DataItem).ServiceChannel.Description;