DataGrid Update event

[csnyder]

I am working through a walkthrough that MS provided, and their code seems to be incorrect. I placed a DataGrid on an asp page, and the data shows up, but when I click edit, then click update, I get an error. Here is the code for the Update event:

		private void DataGrid1_UpdateCommand(object source, 
			System.Web.UI.WebControls.DataGridCommandEventArgs e)
		{
			//change the data in the dataset
			for (int i = 0; i < AuthorData.authors.Columns.Count; i++)
			{
				TextBox t =  (TextBox) (e.Item.Cells[i].Controls[0]);  //***THE ERROR HAPPENS HERE
				DataRow row = AuthorData.authors[e.Item.DataSetIndex];
				row[AuthorData.authors.Columns[i - 1].Caption] = t.Text;
			}

			//Update the database
			if (AuthorData.HasChanges())
			{
				AuthorsWebClient.localhost.AuthorsService ws = new AuthorsWebClient.localhost.AuthorsService();
				ws.Credentials = System.Net.CredentialCache.DefaultCredentials;
				
				AuthorsWebClient.localhost.authors1 diffAuthors = new AuthorsWebClient.localhost.authors1();
				diffAuthors.Merge(AuthorData.GetChanges());

				ws.UpdateAuthors(diffAuthors);
				AuthorData.Merge(diffAuthors);
			}

			//Take row off of edit mode and display the new data
			DataGrid1.EditItemIndex = -1;
			DataGrid1.DataBind();
		}

The problem is it doesn't seem to like the idea of casting the cell's control to a textbox, but that's even the way MDSN shows it being done. Is this incorrect code, or is something else wrong?

Thanks.