After changing DataSource, why does DataGridView show rows only after sorting?

Question

I am trying to make a DataGridView control get populated from a DataTable, that itself gets filled with the results of a sql query on a Oracle database. This should happen after double-clicking the table name from a ListBox control.

This works fine the first time I double-click a table name, but the second time it will only show the column names and no rows.

What I have discovered is that sorting the DataGridView based on any column will cause the rows to suddenly appear, which makes me suspect some kind of graphical/rendering glitch.

Is this expected behavior?

// event handler for ListBox
private void tables_MouseDoubleClick(object sender, MouseEventArgs e)    
{
    // tables is a ListBox populated with table names
    int index = this.tables.IndexFromPoint(e.Location);     
    String table_name;
    if (index != System.Windows.Forms.ListBox.NoMatches)
    {
        // reusing the DataTable
        dt.Reset();     
        table_name =tables.Items[index].ToString();
        OracleCommand cmd = new OracleCommand();
        cmd.Connection = con;
        // case sensitive
        cmd.CommandText = String.Format(@"select * from ""{0}""",table_name);
        cmd.CommandType = CommandType.Text;
        OracleDataAdapter da = new OracleDataAdapter(cmd);
        da.MissingSchemaAction = MissingSchemaAction.AddWithKey;
        da.Fill(dt);
        dt.TableName = table_name;
        label7.Text = table_name;
        // these three lines don't actually accomplish anything in this case
        table.DataSource = null;    
        table.Rows.Clear();
        table.DataSource = dt;

        // uncommenting these lines produces the expected behavior 
        //DataGridViewColumn c = table.Columns[0];      
        //table.Sort(c,System.ComponentModel.ListSortDirection.Descending);
    }
}

After second double-click(without sorting)

After second double-click(with sorting)

Answer 1

Looks like the problem is caused by the DataTable.Reset call.

Although it's not your code problem (most likely a bug in DataTable or DataView), I would suggest using Clear method instead of Reset or creating a new DataTable instance.