calling Rebind() on datagrid raises an error after a call to BringIndexIntoView()

[Andrea]

Hi all, it's a long story, I have to show data in a grid, I were forced to use a datatable to represent records, luckily the radgridview works like a charm with datatables.

When i add a record to the datatable I call Rebind to let the grid stay in sync. And that worked fine for months.

Now the customer wants that when a record is inserted the grid scroll to show the latest record inserted.

So i tried the scrollintoview with no success. Then i used the BringIndexIntoView that worked.

But after the call to BringIndexIntoView the following call to Rebind generate a NullReferenceException.

Also note that if I try to catch the exception and show a standard windows messagebox the messagebox too raise an exception. Seems like the call to BringIndexIntoView messed up the program.

To reproduce the error i created a project if that can help. Just copy into a new VS2010 WPF project named WpfApplication1 using telerik 2010 Q1 SP2 and framework 4.0.

When running click on reset datasource then click twice on add record.

//MainWindow.xaml.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.Data;

namespace WpfApplication1
{
    public partial class MainWindow : Window
    {
        SampleData sd;
        public MainWindow() {
            InitializeComponent();
        }
        private void button1_Click(object sender, RoutedEventArgs e) {
            BindToNewDS();
        }
        private void BindToNewDS()  {
            sd = new SampleData(50);
            radGridView1.ItemsSource = sd.TheTable;
        }
        private void button2_Click(object sender, RoutedEventArgs e)  {
            int idx = sd.CreateSampleRecord();
            radGridView1.Rebind();

            DataRow dr = (radGridView1.ItemsSource as DataTable).Rows
                    .Find(new Object[] { idx });

            if (radGridView1.Items.Contains(dr))
            {
                int iof = radGridView1.Items.IndexOf(dr);
                radGridView1.BringIndexIntoView(iof);
            }
        }
    }
}

MainWindow.xaml

<Window x:Class="WpfApplication1.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525" xmlns:telerik="http://schemas.telerik.com/2008/xaml/presentation">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="45"></RowDefinition>
            <RowDefinition Height="*"></RowDefinition>
        </Grid.RowDefinitions>
        <telerik:RadGridView  ShowInsertRow="False" CanUserInsertRows="False" RowHeight="22"
            SelectionMode="Extended" Grid.Row="1" Name="radGridView1"
            IsReadOnly="True">
            <telerik:RadGridView.Columns>
            </telerik:RadGridView.Columns>
        </telerik:RadGridView>
        <Button Content="Reset datasource" Height="29" HorizontalAlignment="Left" Margin="16,11,0,0" Name="button1" VerticalAlignment="Top" Width="94" Click="button1_Click" />
        <Button Content="Add record and scroll to" Height="30" HorizontalAlignment="Left" Margin="132,10,0,0" Name="button2" VerticalAlignment="Top" Width="144" Click="button2_Click" />
    </Grid>
</Window>

 

//SampleData.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.ComponentModel;
using System.Data;

namespace WpfApplication1
{
    class SampleData
    {
        //define fixed columns
        private DataColumn[] fixedColumns = new DataColumn[] {
                new DataColumn("Equipment", typeof(string)),
                new DataColumn("Place Of Receipt", typeof(string)),
                new DataColumn("Port Of Load", typeof(string)),
                new DataColumn("Port Of Discharge", typeof(string)),
                new DataColumn("Delivery Place", typeof(string))
            };
        //define variable columns, only a random subset of these columns will be added to resulting table
        private DataColumn[] varColumns = new DataColumn[] {
                new DataColumn("Freight", typeof(decimal)),
                new DataColumn("Bunker", typeof(decimal)),
                new DataColumn("Peak season", typeof(decimal)),
                new DataColumn("Pickup costs", typeof(decimal)),
                new DataColumn("Delivery costs", typeof(decimal))
            };
        private string[][] sampleData = new string[][] {
                new string[] {"Equipment", "20 box", "20 o.t.", "40 box", "40 o.t.", "40 h.c."},
                new string[] {"Place Of Receipt", "Lyon", "Tolouse", "Torino", "Milano", "Verona", "Madrid"},
                new string[] {"Port Of Load", "Marseille", "Genova", "La Spezia", "Barcelona", "Napoli"},
                new string[] {"Port Of Discharge", "New York", "Montreal ramp", "Norfolk", "Miami", "Savannah"},
                new string[] {"Delivery Place", "Atlanta", "Jersey City, NJ", "Edison, NJ", "Oaks, PA", "Taftsville, CT"},
            };
        private Random randGenerator = new Random();
        private int LastID = 0;

        public SampleData(int initialRecordCount)
        {
            GenerateTableDefinition();
            CreateSampleRecord();
            for (int i = 1; i < initialRecordCount; ++i)
                CreateSampleRecord();
        }

        public int CreateSampleRecord()
        {
            var row = m_TheTable.NewRow();
            LastID += randGenerator.Next(99)+1;
            row["ID"] = LastID;
            m_TheTable.Rows.Add(row);

            foreach (DataColumn dc in m_TheTable.Columns)
            {
                string[] sample;
                int randIdx;
                sample = sampleData.FirstOrDefault(a => a[0].Equals(dc.ColumnName));
                if (sample != null)
                {
                    randIdx = randGenerator.Next(sample.Count() - 2);
                    row[dc] = sample[randIdx + 1];
                }
                if (dc.DataType == typeof(decimal))
                {
                    row[dc] = (decimal)(randGenerator.Next(60) * 50);
                }
            }
            return LastID;
        }
        private void GenerateTableDefinition()
        {
            //creating table
            DataTable dt = new DataTable("FreightRates");
            //creating primary key
            dt.Columns.Add(new DataColumn("ID", typeof(int)));

            //adding fixed columns to table
            foreach (DataColumn dc in fixedColumns)
            {
                dt.Columns.Add(dc);
            }

            //selecting randomly a number of variable columns to be added to the table
            List<DataColumn> varColumnList = varColumns.ToList();

            int numberOfVariableColumns = randGenerator.Next(varColumnList.Count() - 1);

            for (int i = 0; i < numberOfVariableColumns; ++i)
            {
                int randomlySelectedColumn = randGenerator.Next(varColumnList.Count() - 1);
                dt.Columns.Add(varColumnList[i]);
                varColumnList.RemoveAt(i);
            }
            //expliciting primary key
            dt.PrimaryKey = new DataColumn[] { dt.Columns["ID"] };
            TheTable = dt;
        }

        private DataTable m_TheTable;
        public DataTable TheTable
        {
            get { return this.m_TheTable; }
            private set
            {
                if (value != this.m_TheTable)
                {
                    this.m_TheTable = value;
                }
            }
        }
    }
}

[Vlad]

Hello Andrea,

 Have you tried our latest official version (Q2 2011) in your scenario? Today we will release our Q2 2011 SP1 - you can try the service pack directly. 

Best wishes,
Vlad
the Telerik team