Question

I’m not so familiar with bindingsources. The short question is: How do you bind a chart to a datasource so that when the BindingNavigator is changed the chart display updates?

My long winded explanation is below:

I have a datasource I have imported into C# VS 2010 Express. It is a related dataset, in that there are 2 tables (Asset, Historical_prices), where each asset has a table of related historical prices.

I simply draged and droped my datasource into the form and was able to create the view I wanted, with the help of the BindingNavigator. I dragged a DataGrid view of the Historical_prices table into the form as well, and it updates when the BindingNavigator is clicked

I then created a chart in the form, which I selected the DataSource as the historical_pricesBindingSource. It loads

I want to be able to update the chart with different Historical_prices when the BindingBavigator is changed but it currently doesnt. Any ideas?

I tried adding chart1.Update(); in the BindingNavigatorSaveItem_Click event but no dice.

Thank you kindly

Answer 1

The Binding needs to actually be databound instead of just assigned. What you have done is essentially created a One-Time binding that occurs at Runtime during Initialization or Value Assignment.

This means that your Target (The Chart) Only Updates One-Time, when the Source (the DataSource) is Created by the view.

What you are looking for is a Two-Way binding. So that the Target is updated ANYTIME the Source is modified.

To Achieve this you would generally need to bind the DataSource to the TargetProperty using the Two-Way binding syntax.

<Toolkit:Chart x:Name="myChart" DataSource="{Binding historical_PricesDataSource, Mode=TwoWay}" />

Your Data Source will need to Implement the INotifyPropertyChanged Interface though in order to notify the UI that it needs to be updated.

The Code for Implementing INotifyPropertyChanged is:

public event PropertyChangedEventHandler PropertyChanged = delegate{};

    // This method is called by the Set accessor of each property. 
    // The CallerMemberName attribute that is applied to the optional propertyName 
    // parameter causes the property name of the caller to be substituted as an argument. 
    private void NotifyPropertyChanged([CallerMemberName] String propertyName = "")
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }

For More info in INotifyPropertyChanged: http://msdn.microsoft.com/en-us/library/ms229614.aspx