Got a simple ASPX page (.NET v1.1) with a DataGrid displaying a list of
widgets. If the page has a QueryString called WidgetId specific, I need
to automatically mark the specific DataGridItem as selected.

Pretty simple, here's what I did:

for (int i=0; i<dgWidgets.Items.Count; i++)
{
 DataGridItem oDataGridItem = dgWidgets.Items[i];
 if (oDataGridItem.Cells[0].Text == WidgetId)
 {
   dgWidgets.SelectedIndex = i;
   dgWidgets_OnSelectedIndexChanged(this, new EventArgs());
   return;
 }
}

Works like a charm ... However, if the DataGridItem I want to select is
not on the first page of the DataGrid, I run into problems. So, if I
modify the above code slightly to account for DataGrid Paging, here's
what I come up with.

for (int i=0; i<dgWidgets.Items.Count; i++)
{
 DataGridItem oDataGridItem = dgWidgets.Items[i];
 if (oDataGridItem.Cells[0].Text == WidgetId)
 {
   dgWidgets.SelectedIndex = i;
   if (i > dgWidgets.PageSize)
   {
     int iPageIndex =
Convert.ToInt32(Math.Ceiling(i/dgWidgets.PageSize));
     dgWidgets.CurrentPageIndex = iPageIndex;
     dgWidgets_OnPageIndexChanged(this, new
DataGridPageChangedEventArgs(this, iPageIndex));
   }
   dgWidgets_OnSelectedIndexChanged(this, new EventArgs());
   return;
 }
}

However, when stepping through this, I realized that when paging is
enabled, and I'm iterating through the DataGridItems collection, the
collection only contains the Items in the "current page"

Sort of a catch 22 here ... I need to calculate the proper page index
that an Item sits in, but have no access to the complete collection ...

Maybe use the index of the DataTable instead??