Is it possible to have autoscrollbar feature? The ScrollScale enlarges the current chart. There is a chance that I can have 10 rows or 100 rows in my chart. Its based on database and can get the no. of rows only at run time. In that case how I can specify the ScrollScale.

Hi Graham, how to enable the click and drag the webchat to perform zoom? thx

Many thanks Graham.

Your code helped.

Yet another option would be to throw the entire chart into a ScrollViewer, setting the HorizontalScrollbarVisibility to Auto, but this may not provide the user experience you are searching for.

You could try something like this to automatically enable the scrollbar:

<UserControl x:Class="SilverlightApplication13.MainPage"

    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

    xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"

    mc:Ignorable="d" d:DesignWidth="640" d:DesignHeight="480"

    xmlns:igChart="clr-namespace:Infragistics.Silverlight.Chart;assembly=Infragistics.Silverlight.DataVisualization.Chart.v9.2"

    xmlns:igControls="clr-namespace:Infragistics.Silverlight.Controls;assembly=Infragistics.Silverlight.DataVisualization.Controls.v9.2">

    <Grid x:Name="LayoutRoot">

        <StackPanel>

            <igChart:XamWebChart x:Name="chart" Width="400" Height="400">

                <igChart:XamWebChart.Axes>

                    <igChart:Axis AxisType="PrimaryX"

                              ScrollEnabled="False"

                              ScrollScale="0.75"

                              ScrollPosition="0"/>

                </igChart:XamWebChart.Axes>

                <igChart:XamWebChart.Series>

                    <igChart:Series ChartType="Column"

                                DataSource="{Binding Data}"

                                DataMapping="Label = Label; Value = Value"/>

                </igChart:XamWebChart.Series>

            </igChart:XamWebChart>

            <Button Content="Add Data Point" HorizontalAlignment="Left" Click="Button_Click"/>

        </StackPanel>

    </Grid>

</UserControl>

with code behind:

public partial class MainPage : UserControl

    {

        private ChartDataViewModel _vm;

        private Axis _xAxis;

        public MainPage()

        {

            InitializeComponent();

            foreach (Axis axis in chart.Axes)

            {

                if (axis.AxisType == AxisType.PrimaryX)

                {

                    _xAxis = axis;

                }

            }

            _vm = new ChartDataViewModel(4);

            _vm.Data = new ObservableCollection<DataItemViewModel>()

            {

                new DataItemViewModel() {Label = "Test1", Value = 4},

                new DataItemViewModel() {Label = "Test2", Value = 5},

                new DataItemViewModel() {Label = "Test3", Value = 2},

                new DataItemViewModel() {Label = "Test4", Value = 1}

            };

            _xAxis.ScrollEnabled = _vm.ScrollbarEnabled;

            _vm.PropertyChanged +=

                new PropertyChangedEventHandler(vm_PropertyChanged);

            DataContext = _vm;

        }

        void vm_PropertyChanged(object sender, PropertyChangedEventArgs e)

        {

            //can't bind the chart axis against at the moment, so setting

            //from event handler.

            if (e.PropertyName == "ScrollbarEnabled")

            {

                _xAxis.ScrollEnabled = _vm.ScrollbarEnabled;

            }

        }

        private int _counter = 5;

        private void Button_Click(object sender, RoutedEventArgs e)

        {

            DataItemViewModel _dvm = new DataItemViewModel()

            {

                Label = "Test" + _counter,

                Value = _counter

            };

            _vm.Data.Add(_dvm);

            _counter++;

        }

    }

    public class DataItemViewModel

    {

        public string Label { get; set; }

        public double Value { get; set; }

    }

    public class ChartDataViewModel : INotifyPropertyChanged

    {

        public ChartDataViewModel(int threshold)

        {

            _threshold = threshold;

        }

        private int _threshold;

        private ObservableCollection<DataItemViewModel> _data;

        public ObservableCollection<DataItemViewModel> Data

        {

            get

            {

                return _data;

            }

            set

            {

                if (_data != null)

                {

                    _data.CollectionChanged -=

                        new NotifyCollectionChangedEventHandler(OnDataChanged);

                }

                if (value != null)

                {

                    value.CollectionChanged +=

                        new NotifyCollectionChangedEventHandler(OnDataChanged);

                }

                _data = value;

                UpdateScrollbarEnabled();

                if (PropertyChanged != null)

                {

                    PropertyChanged(this,

                        new PropertyChangedEventArgs("Data"));

                }

            }

        }

        private bool _scrollbarEnabled;

        public bool ScrollbarEnabled

        {

            get

            {

                return _scrollbarEnabled;

            }

            private set

            {

                _scrollbarEnabled = value;

                if (PropertyChanged != null)

                {

                    PropertyChanged(this,

                        new PropertyChangedEventArgs("ScrollbarEnabled"));

                }

            }

        }

        private void OnDataChanged(object sender, NotifyCollectionChangedEventArgs e)

        {

            UpdateScrollbarEnabled();

        }

        private void UpdateScrollbarEnabled()

        {

            if (Data.Count > _threshold)

            {

                ScrollbarEnabled = true;

            }

            else

            {

                ScrollbarEnabled = false;

            }

        }

        #region INotifyPropertyChanged Members

        public event PropertyChangedEventHandler PropertyChanged;

        #endregion

    }

Another option you would have here is to examine the width and height of the chart that it wants to take, and enable the scrollbar based on these settings.

-Graham