Forms Data Controls :: Cascading Dropdown List In A GridView Control In Edit Mode Error

I'm trying to follow this article on cascading dropdown list in a GridView control in edit mode (except I'm using C#) [URL] I keep getting this error message "ProjectID is neither a DataColumn nor a DataRelation for table DefaultView."

protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
{
if ((e.Row.RowState & DataControlRowState.Edit) == DataControlRowState.Edit)
{
DataRowView dv = (DataRowView)e.Row.DataItem;
//// Preselect correct value in Projects list
DropDownList listProjects = (DropDownList)e.Row.FindControl("DropDownList1");
listProjects.SelectedValue = dv["ProjectID"].ToString(); // *****************this is where I get the error *********
// Databind list of categories in dependent drop-down list
DropDownList listCategories = (DropDownList)e.Row.FindControl("DropDownList2");
SqlDataSource dsc = (SqlDataSource)e.Row.FindControl("sdsDDL2");
dsc.SelectParameters["ProjectName"].DefaultValue = dv["ProjectName"].ToString();
listCategories.DataBind();
listCategories.SelectedValue =(dv["CategoryID"].ToString());
}
<asp:SqlDataSource ID="SqlDataSource1" runat="server"
ConnectionString="<%&#36; ConnectionStrings:ttuser %>" SelectCommand="SELECT
TE.TimeEntryID,
P.ProjectName,
CAT.CategoryName,
TE.TimeEntryDescription,
TE.TimeEntryDuration,
TE.TimeEntryDate
FROM dbo.aspnet_starterkits_TimeEntry TE inner join
dbo.aspnet_starterkits_ProjectCategories CAT on
TE.CategoryID=CAT.CategoryID inner join
dbo.aspnet_starterkits_Projects P on
CAT.ProjectID=P.ProjectID
Where TimeEntryUserID=(SELECT UserId FROM dbo.aspnet_Users WHERE
UserName=@UserName) AND
TE.TimeEntryDate=@WeekEnding
" OldValuesParameterFormatString="original_{0}" UpdateCommand="UPDATE dbo.aspnet_starterkits_TimeEntry
SET
TimeEntryDescription=@TimeEntryDescription,
TimeEntryDuration=@TimeEntryDuration,
TimeEntryDate=@TimeEntryDate
WHERE
TimeEntryID=@original_TimeEntryID">
<SelectParameters>
<asp:ControlParameter ControlID="UserList" Name="UserName"
PropertyName="SelectedValue" />
<asp:ControlParameter ControlID="WeekEnding2" Name="WeekEnding"
PropertyName="Text" />
</SelectParameters>
<UpdateParameters>
<asp:Parameter Name="TimeEntryDescription" />
<asp:Parameter Name="TimeEntryDuration" />
<asp:Parameter Name="TimeEntryDate" />
<asp:Parameter Name="original_TimeEntryID" />
</UpdateParameters>
</asp:SqlDataSource>
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False"
DataSourceID="SqlDataSource1" BorderWidth="0px"
BorderStyle="None" Width="100%" CellPadding="2" PageSize="25"
DataKeyNames="TimeEntryID" onrowdatabound="GridView1_RowDataBound"
onrowupdating="GridView1_RowUpdating" >
<Columns>
<%--<asp:CommandField ShowEditButton="True" />--%>
<asp:BoundField DataField="TimeEntryID" HeaderText="ID"
SortExpression="TimeEntryID" InsertVisible="False" ReadOnly="True"
ItemStyle-HorizontalAlign="Center" >
<ItemStyle HorizontalAlign="Center"></ItemStyle>
</asp:BoundField>
<asp:TemplateField HeaderText="Project" SortExpression="ProjectName">
<EditItemTemplate>
<asp:DropDownList
ID="DropDownList1"
runat="server"
DataSourceID="sdsDdlProjectsEdit"
DataTextField="ProjectName"
DataValueField="ProjectID"
AutoPostBack="True"
onselectedindexchanged="DropDownList1_SelectedIndexChanged">
</asp:DropDownList>
<asp:SqlDataSource
ID="sdsDdlProjectsEdit"
runat="server"
ConnectionString="<%&#36; ConnectionStrings:ttuser %>"
SelectCommand="SELECT ProjectID,ProjectName FROM dbo.aspnet_starterkits_Projects">
</asp:SqlDataSource>
</EditItemTemplate>
<ItemTemplate>
<asp:Label ID="Label2" runat="server" Text='<%# Bind("ProjectName") %>'></asp:Label>
</ItemTemplate>
<ItemStyle HorizontalAlign="Center" />
</asp:TemplateField>
<asp:TemplateField HeaderText="Category" SortExpression="CategoryName">
<EditItemTemplate>
<asp:DropDownList
ID="DropDownList2"
runat="server"
DataSourceID="sdsDDL2"
DataTextField="CategoryName"
DataValueField="CategoryID">
</asp:DropDownList>
<asp:SqlDataSource
ID="sdsDDL2"
runat="server"
ConnectionString="<%&#36; ConnectionStrings:ttuser %>"
SelectCommand="SELECT CategoryID,CategoryName FROM dbo.aspnet_starterkits_ProjectCategories WHERE ProjectID=@ProjectID">
<SelectParameters>
<asp:Parameter Name="ProjectID" />
</SelectParameters>
</asp:SqlDataSource>
</EditItemTemplate>
<ItemTemplate>
<asp:Label ID="Label1" runat="server" Text='<%# Bind("CategoryName") %>'></asp:Label>
</ItemTemplate>
<ItemStyle HorizontalAlign="Center" />
</asp:TemplateField>
<asp:BoundField DataField="TimeEntryDescription" HeaderText="Description"
SortExpression="TimeEntryDescription" ItemStyle-HorizontalAlign="Center" >
<ItemStyle HorizontalAlign="Center"></ItemStyle>
</asp:BoundField>
<asp:BoundField DataField="TimeEntryDuration" HeaderText="Hours"
SortExpression="TimeEntryDuration" ItemStyle-HorizontalAlign="Center" >
<ItemStyle HorizontalAlign="Center"></ItemStyle>
</asp:BoundField>
<asp:BoundField ApplyFormatInEditMode="True" DataField="TimeEntryDate"
DataFormatString="{0:d}" HeaderText="Week Ending"
SortExpression="TimeEntryDate" ItemStyle-HorizontalAlign="Center" >
<ItemStyle HorizontalAlign="Center"></ItemStyle>
</asp:BoundField>
<asp:CommandField ShowEditButton="True" HeaderText="Edit" ButtonType="Image" EditImageUrl="images/icon-edit.gif"
UpdateImageUrl="images/icon-save.gif" CancelImageUrl="images/icon-cancel.gif" />
</Columns>
</asp:GridView>