Why is my GridViewRow.DataItemIndex incorrect and DataItem null?

Question

I'm trying to immediately set a row to Edit mode after it is created. However, my GridViewRow has an incorrect DataItemIndex and a null DataItem...

Here's a general idea of what my code is doing: (pseudo VB code)

Protected Sub gvItems_RowCommand(....)
  if (e.CommandName = 'New')
  Begin
    // create new empty and add it to my data table
    m_dtItems.Rows.Add(m_dtItems.NewRow()) // m_dtItems is a DataTable

    // rebind the gridview to the modified data table
    gvItems.DataSource = m_dtItems
    gvItems.DataBind()

    // loop through grid view to find the row we just inserted
    Dim newRowDataItemIndex As Integer = m_dtItems.Rows.IndexOf(dRow)

    For each row in gvItems.Rows
       if (row.DataItemIndex = newRowDataItemIndex)
         gvItems.EditIndex = row.RowIndex

    // rebind the grid so the edit index takes effect
    gvItems.DataSource = m_dtItems
    gvItems.DataBind()
  End
End Sub

The problem is that GridViewRow.DataItemIndex is not correct. It seems to be equal to the RowIndex. Also, my GridViewRow.DataItem is null except inside GridViewRow_RowDataBound event.

I'm not using paging or sorting either which I know causes problems.

What am I doing wrong?

Answer 1

It looks like the problem was that a data table can contain deleted rows (eg. DataRow.RowState = Deleted) and the grid view only contains "valid" rows. Therefore, the DataItemIndexes do not match and you can also get exceptions if you try to refer to a deleted row.

The solution was to bind the grid view to a data view (myDataTable.DefaultView) with a RowStateFilter of CurrentRowsOnly and then do all changes (add, edit, and deletions) through the data view.