DataGridView DataSource

[joe_pool_is]

I have two procedures that work together. If a child node is selected on a TreeView control, the records for the parent are displayed and focus is given to the child record. If the parent node is selected, I simply want to display the records associated with the parent node.

It worked ok (by displaying all of the data rows) until I tried to apply a RowFilter to the DefaultView. Now, the DataGridView contains 0 Rows (see line 576 below), and my app would sit there and loop until it reaches a stack overflow (because of the test condition on line 552 and the recursive call on line 554) if I tried to deply it now. Instead of getting rid of the loop condition, Id like to figure out how to fix the DataGridViews DataSource problem, because my code does not seem to take the statement like it is supposed to.

One example that I saw showed to use DataGridViews DataBind method afterward applying a DataSource (line 575 below), but I dont know how to "unbind" the DataGridView for the next time I need to display a different table.

535: private void DataGrid_FindRow(TreeNode node)
536: {
537:   string colName = node.Parent.Tag.ToString();
538:   if (DataGridView1.Columns.Contains(colName) == false)
539:   {
540:     DataGrid_Show(node.Parent);
541:   }
542:   if (DataGridView1.Columns.Contains(colName) == true)
543:   { // just in case there was an error
544:     DataGridViewCell cell = null;
545:     for (int i = 0; (i < DataGridView1.Rows.Count) && (cell == null); i++)
546:     {
547:       if (DataGridView1.Rows[i].Cells[colName].Value.ToString().Trim() == node.Text)
548:       {
549:         cell = DataGridView1.Rows[i].Cells[colName];
550:       }
551:     }
552:     if (cell == null) {
553:       DataGrid_Show(node.Parent);
554:       DataGrid_FindRow(node);
555:     } else {
556:       DataGridView1.CurrentCell = cell;
557:     }
558:   }
559: }
560: 
561: private void DataGrid_Show(TreeNode node)
562: {
563:   if (0 < DataGridView1.Columns.Count)
564:     DataGridView1.Columns.Clear();
565:   if (0 < DataGridView1.Rows.Count)
566:     DataGridView1.Rows.Clear();
567:   if (Global.CpAppDataSet.Tables.Contains(node.Parent.Tag.ToString()) == true)
568:   {
569:     DataTable dt = Global.CpAppDataSet.Tables[node.Parent.Tag.ToString()].Copy();
570:     m_title = string.Format("{0} LIKE {1}", node.Tag.ToString(), node.Text);
571:     dt.DefaultView.RowFilter = m_title;
572:     dt.AcceptChanges(); // dt: Columns.Count = 9; Rows.Count = 1589
573:     if (dt.Columns.Contains(node.Tag.ToString()) == true)
574:     {
575:       DataGridView1.DataSource = dt.DefaultView;
576:       DataGridView1.Refresh(); // DataGridView1: Columns.Count = 9; Rows.Count = 0
577:     }
578:     DataGridView1.AutoResizeColumns(DataGridViewAutoSizeColumnsMode.AllCells);
579:     string output = string.Format("{0} - {1} Records returned", node.Tag.ToString(), DataGridView1.Rows.Count);
580:     UpdateStatusBar(output);
581:   }
582: }

As an FYI: If I do *not* create the DataTable copy on line 569 or apply a RowFilter on 571, the code correctly selects the row entry that matches the entry in the TreeView - but it also shows all 1589 records, whereas I want to filter this to only show the 10-100 records associated with that records parent node.

I hope this makes sense to others, and I hope my code example isnt too long and is easy enough to understand.