The FunctionBindingBehavior allows you to use a ViewModel function to calculate a control property. The example uses this behavior to bind the ChartControl to the GetFilteredItems function and pass SelectionRangeStart and SelectionRangeEnd properties of the RangeControl to the function.
C#public IList<DataItem> GetFilteredItems(DateTime start, DateTime end) {
return this.Points.Where(x => x.Date.Date >= start && x.Date.Date <= end).OrderByDescending(x => x.ValueSummary).ToList();
}
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Example Code
FunctionBindingExample/View/MainView.xaml
XAML<UserControl
x:Class="FunctionBindingExample.View.MainView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:dxe="http://schemas.devexpress.com/winfx/2008/xaml/editors"
xmlns:dxmvvm="http://schemas.devexpress.com/winfx/2008/xaml/mvvm"
xmlns:dxcr="http://schemas.devexpress.com/winfx/2008/xaml/charts/rangecontrolclient"
xmlns:dxc="http://schemas.devexpress.com/winfx/2008/xaml/charts"
xmlns:vm="clr-namespace:FunctionBindingExample.ViewModel"
mc:Ignorable="d" d:DesignHeight="300" d:DesignWidth="300"
DataContext="{dxmvvm:ViewModelSource Type=vm:MainViewModel}" >
<Grid>
<Grid.RowDefinitions>
<RowDefinition />
<RowDefinition Height="100"/>
</Grid.RowDefinitions>
<dxc:ChartControl Name="chartControl1" Grid.Column="1" Margin="10">
<dxc:ChartControl.Diagram>
<dxc:SimpleDiagram2D>
<dxc:SimpleDiagram2D.Series>
<dxc:FunnelSeries2D x:Name="Series" ArgumentDataMember="Date" LegendTextPattern="{}{A: MM-yyyy}: {VP:##.##%}" ValueDataMember="ValueSummary" ToolTipEnabled="True" LabelsVisibility="True">
<dxc:FunnelSeries2D.Label>
<dxc:SeriesLabel TextPattern="{}{VP:##.##%}" dxc:FunnelSeries2D.LabelPosition="Center"/>
</dxc:FunnelSeries2D.Label>
</dxc:FunnelSeries2D>
</dxc:SimpleDiagram2D.Series>
</dxc:SimpleDiagram2D>
</dxc:ChartControl.Diagram>
<dxc:ChartControl.Legend >
<dxc:Legend Orientation="Horizontal" HorizontalPosition="Center" VerticalPosition="BottomOutside" BorderThickness="0" Margin="0,0,0,0"/>
</dxc:ChartControl.Legend>
<dxmvvm:Interaction.Behaviors>
<dxmvvm:FunctionBindingBehavior
Property="DataSource"
Target="{Binding ElementName=Series}"
Function="GetFilteredItems"
Source="{Binding}"
Arg1="{Binding SelectionRangeStart, ElementName=rangeControl}"
Arg2="{Binding SelectionRangeEnd, ElementName=rangeControl}"/>
</dxmvvm:Interaction.Behaviors>
</dxc:ChartControl>
<dxe:RangeControl Name="rangeControl" AllowZoom="False" Grid.Row="1" Margin="10" SelectionRangeStart="1/1/2015" SelectionRangeEnd="7/1/2015" ShowRangeBar="False">
<dxcr:DateTimeChartRangeControlClient SnapAlignment="Month" ArgumentLabelFormatString="{}{0:MMMM-yyyy}" ItemsSource="{Binding Points}" ArgumentDataMember="Date" ValueDataMember="ValueSummary"/>
</dxe:RangeControl>
</Grid>
</UserControl>
FunctionBindingExample/ViewModel/MainViewModel.cs(vb)
C#using System;
using System.Linq;
using DevExpress.Mvvm.POCO;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using FunctionBindingExample.Common;
namespace FunctionBindingExample.ViewModel {
public class MainViewModel {
protected MainViewModel() {
Points = new ObservableCollection<DataItem>(){
DataItem.Create(new DateTime(2015, 02, 18), 3.47, "A"),
DataItem.Create(new DateTime(2015, 01, 01), 2.08, "B"),
DataItem.Create(new DateTime(2015, 02, 01), 2.42, "C"),
DataItem.Create(new DateTime(2015, 03, 01), 2.78, "E"),
DataItem.Create(new DateTime(2015, 04, 01), 2.78, "F"),
DataItem.Create(new DateTime(2015, 05, 01), 2.57, "G"),
DataItem.Create(new DateTime(2015, 06, 01), 2.69, "H"),
DataItem.Create(new DateTime(2015, 07, 01), 2.96, "I"),
DataItem.Create(new DateTime(2015, 08, 01), 2.36, "J"),
DataItem.Create(new DateTime(2015, 09, 01), 1.97, "K"),
DataItem.Create(new DateTime(2015, 10, 11), 2.75, "L"),
DataItem.Create(new DateTime(2015, 11, 12), 3.45, "M"),
DataItem.Create(new DateTime(2015, 12, 13), 4.08, "N"),
DataItem.Create(new DateTime(2014, 01, 14), 3.47, "P"),
DataItem.Create(new DateTime(2014, 02, 15), 2.64, "Q"),
DataItem.Create(new DateTime(2014, 03, 16), 4.59, "R"),
DataItem.Create(new DateTime(2014, 04, 17), 1.54, "S"),
DataItem.Create(new DateTime(2014, 05, 18), 4.12, "T"),
DataItem.Create(new DateTime(2014, 06, 19), 3.47, "U"),
};
}
public static MainViewModel Create() {
return ViewModelSource.Create(()=>new MainViewModel());
}
public virtual ObservableCollection<DataItem> Points { get; set; }
public IList<DataItem> GetFilteredItems(DateTime start, DateTime end) {
return this.Points.Where(x => x.Date.Date >= start && x.Date.Date <= end).OrderByDescending(x => x.ValueSummary).ToList();
}
}
}
FunctionBindingExample/Common/DataItem.cs(vb)
C#using DevExpress.Mvvm.POCO;
using System;
namespace FunctionBindingExample.Common {
public class DataItem {
protected DataItem(DateTime date, double valueSummary, string stageName) {
Date = date;
ValueSummary = valueSummary;
StageName = stageName;
}
public static DataItem Create(DateTime date, double valueSummary, string stageName) {
return ViewModelSource.Create(() => new DataItem(date, valueSummary, stageName));
}
public DateTime Date { get; set; }
public double ValueSummary { get; set; }
public string StageName { get; set; }
}
}