Skip to main content
All docs
V24.2

DevExpress v24.2 Update — Your Feedback Matters

Our What's New in v24.2 webpage includes product-specific surveys. Your response to our survey questions will help us measure product satisfaction for features released in this major update and help us refine our plans for our next major release.

Take the survey Not interested

SankeyLayoutAlgorithmBase Class

The base class for classes that implement Sankey layout algorithms.

Namespace: DevExpress.Xpf.Charts.Sankey

Assembly: DevExpress.Xpf.Charts.v24.2.dll

NuGet Package: DevExpress.Wpf.Charts

#Declaration

public abstract class SankeyLayoutAlgorithmBase :
    ChartDependencyObject,
    ISankeyLayoutAlgorithm

The following members return SankeyLayoutAlgorithmBase objects:

#Remarks

To implement a custom layout, create a descendant of the SankeyLayoutAlgorithmBase class. Override the SankeyLayoutAlgorithmBase.CalculateNodeBounds method to specify node bounds:

Custom Sankey layout algorithm

<dx:ThemedWindow 
    x:Class="CustomNodeLayout.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:dx="http://schemas.devexpress.com/winfx/2008/xaml/core"
    xmlns:dxsa="http://schemas.devexpress.com/winfx/2008/xaml/sankey"
    xmlns:local="clr-namespace:CustomNodeLayout"
    Title="MainWindow" Height="300" Width="400">
    <Grid>
        <dxsa:SankeyDiagramControl x:Name="sankeyDiagramControl1" 
                                   DataSource="{Binding Data}" 
                                   SourceDataMember="Source" 
                                   TargetDataMember="Target" 
                                   WeightDataMember="Value">
            <dxsa:SankeyDiagramControl.DataContext>
                <local:SankeyViewModel/>
            </dxsa:SankeyDiagramControl.DataContext>
            <dxsa:SankeyDiagramControl.LayoutAlgorithm>
                <local:MyLayoutAlgorithm/>
            </dxsa:SankeyDiagramControl.LayoutAlgorithm>
        </dxsa:SankeyDiagramControl>
    </Grid>
</dx:ThemedWindow>
using DevExpress.Charts.Sankey;
using DevExpress.Xpf.Charts;
using DevExpress.Xpf.Charts.Sankey;
using DevExpress.Xpf.Core;
using System.Collections.Generic;
using System.Linq;
namespace CustomNodeLayout {
    //...
    public class SankeyViewModel {
        public List<SankeyItem> Data {
            get { return GetData(); }
        }
        public List<SankeyItem> GetData() {
            List<SankeyItem> data = new List<SankeyItem>{
            new SankeyItem { Source = "France", Target = "UK", Value = 53 },
            new SankeyItem { Source = "Australia", Target = "UK", Value = 72 },
            new SankeyItem { Source = "France", Target = "Canada", Value = 81 },
            new SankeyItem { Source = "China", Target = "Canada", Value = 96 },
            new SankeyItem { Source = "UK", Target = "France", Value = 61 },
            new SankeyItem { Source = "Canada", Target = "France", Value = 89 }
        };
            return data;
        }
    }
    public class SankeyItem {
        public string Source { get; set; }
        public string Target { get; set; }
        public double Value { get; set; }
    }
    public class MyLayoutAlgorithm : SankeyLayoutAlgorithmBase {
        void SpreadLevelIndex(ISankeyNodeLayoutItem node, int startingLevelIndex = 0) {
            node.LevelIndex = startingLevelIndex;
            if (node.OutputLinks == null)
                return;
            foreach (var outputLink in node.OutputLinks)
                SpreadLevelIndex(outputLink.Target, startingLevelIndex + 1);
        }
        protected override ChartDependencyObject CreateObject() => new MyLayoutAlgorithm();
        public override void CalculateNodeBounds(IEnumerable<ISankeyNodeLayoutItem> nodes, DevExpress.Utils.DXRectangle bounds) {
            foreach (var node in nodes)
                if (node.InputLinks == null || node.InputLinks.Count == 0)
                    SpreadLevelIndex(node);
            int nodeWidth = bounds.Width / 10;
            int nodeHeight = bounds.Height / 10;
            int levelCount = nodes.Max(node => node.LevelIndex) + 1;
            int spaceBetweenLevels = (bounds.Width - nodeWidth) / (levelCount - 1);
            int maxNodeCountInALevel = nodes.GroupBy(node => node.LevelIndex).Max(group => group.Count());
            int spaceBetweenNodes = (bounds.Height - nodeHeight) / (maxNodeCountInALevel - 1);
            Dictionary<int, int> levelNodeCountPairs = new Dictionary<int, int>();
            foreach (var node in nodes) {
                if (!levelNodeCountPairs.TryGetValue(node.LevelIndex, out int nodeCount))
                    levelNodeCountPairs.Add(node.LevelIndex, 0);
                levelNodeCountPairs[node.LevelIndex]++;
                node.Bounds = new DevExpress.Utils.DXRectangle(bounds.Left + node.LevelIndex * spaceBetweenLevels, bounds.Top + nodeCount * spaceBetweenNodes, nodeWidth, nodeHeight);
            }
        }
    }
}
See Also
xref:DevExpress.Xpf.Charts.Sankey.SankeyLinearLayoutAlgorithm