數據可視化新方式，SankeyDiagramControl類的使用你不能錯過！（Part 2）

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自定義節點

使用SankeyDiagramControl.NodeLabel屬性訪問節點標籤設置，如下選項使您能夠配置節點標籤的文本：

• TextOrientation - 標籤文字方向。
• MaxWidth - 標籤寬度（以像素爲單位）。
• MaxLineCount - 多行文字能夠佔用的行數。
• TextAlignment - 文字對齊。
• Font - 字體參數。

C#

`sankeyDiagramControl1.NodeLabel.TextOrientation = TextOrientation.TopToBottom;
sankeyDiagramControl1.NodeLabel.MaxWidth = 200;
sankeyDiagramControl1.NodeLabel.MaxLineCount = 1;
sankeyDiagramControl1.NodeLabel.TextAlignment = StringAlignment.Center;
sankeyDiagramControl1.NodeLabel.Font = new Font(FontFamily.GenericSerif, 10);`

VB.NET

`sankeyDiagramControl1.NodeLabel.TextOrientation = TextOrientation.TopToBottom
sankeyDiagramControl1.NodeLabel.MaxWidth = 200
sankeyDiagramControl1.NodeLabel.MaxLineCount = 1
sankeyDiagramControl1.NodeLabel.TextAlignment = StringAlignment.Center
sankeyDiagramControl1.NodeLabel.Font = New Font(FontFamily.GenericSerif, 10)`

您還能夠處理CustomizeNode事件來訪問特定節點並根據特定條件對其進行自定義：

C#

`sankeyDiagramControl1.CustomizeNode += OnCustomizeNode;
//...
private void OnCustomizeNode(object sender, CustomizeSankeyNodeEventArgs e) {
if (e.Label.Text == "France" && e.Node.Level == 0) {
e.Label.Font = new Font("Tahoma", 16);
e.Label.Text = "France (Source)";
}
}`

VB.NET

`Private Sub OnCustomizeNode(ByVal sender As Object, ByVal e As CustomizeSankeyNodeEventArgs)
If e.Label.Text Is "France" AndAlso e.Node.Level = 0 Then
e.Label.Font = New Font("Tahoma", 16)
e.Label.Text = "France (Source)"
End If
End Sub`

節點排序

該控件根據基礎數據自動排列節點，若是但願從新排列節點或指定自定義排序順序，請建立一個實現IComparer <SankeyNode>的類。 而後，將此類的對象分配給NodeComparer屬性。

如下代碼按節點的TotalWeight值降序排列它們：

C#

`private void Form1_Load(object sender, EventArgs e) {
sankeyDiagramControl1.NodeComparer = new MyNodeComparer();
}

public class MyNodeComparer : IComparer<SankeyNode> {
public int Compare(SankeyNode x, SankeyNode y) {
return y.TotalWeight.CompareTo(x.TotalWeight);
}
}`

VB.NET

`Friend Class SurroundingClass
Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs)
sankeyDiagramControl1.NodeComparer = New MyNodeComparer()
End Sub

Public Class MyNodeComparer
Inherits IComparer(Of SankeyNode)

Public Function Compare(ByVal x As SankeyNode, ByVal y As SankeyNode) As Integer
Return y.TotalWeight.CompareTo(x.TotalWeight)
End Function
End Class
End Class`

指定節點和連接顏色

Sankey diagram控件使用SankeyPaletteColorizer爲節點着色，使用惟一標籤將調色板中的新顏色應用於每一個節點。 若是惟一標籤的數量超過調色板顏色的數量，則顏色會重複。 要將漸變填充應用於連接，控件將利用源和目標節點顏色。 指定SankeyPaletteColorizer.Palette 屬性來更改用於繪製Sankey diagram的顏色，您能夠選擇預約義的調色板。

C#

`sankeyDiagramControl1.Colorizer = new SankeyPaletteColorizer { Palette = Palettes.NorthernLights };
`
VB.NET

`sankeyDiagramControl1.Colorizer = New SankeyPaletteColorizer With {
.Palette = Palettes.NorthernLights
}`

您還能夠以下建立新的調色板：

C#

`using System.Drawing;
//...
Palette palette = new Palette("Custom") {
Color.Red,
Color.Green,
Color.Blue
};
sankeyDiagramControl1.Colorizer = new SankeyPaletteColorizer { Palette = palette };
`
VB.NET

`Imports System.Drawing
'...
Dim palette As Palette = New Palette("Custom") From {
Color.Red,
Color.Green,
Color.Blue
}
sankeyDiagramControl1.Colorizer = New SankeyPaletteColorizer With {
palette
}`

自定義着色器

要基於自定義算法繪製連接和節點，請建立一個實現ISankeyColorizer 接口的類。 而後，將此類的對象分配給Colorizer屬性。

如下代碼實現了一個着色器，該着色器將隨機顏色應用於節點，並指定用於將漸變填充應用於連接的顏色：

C#

`private void Form1_Load(object sender, EventArgs e) {
sankeyDiagramControl1.Colorizer = new MyColorizer {
LinkSourceColor = Color.Red,
LinkTargetColor = Color.Yellow
};

public class MyColorizer : ISankeyColorizer {
public event EventHandler ColorizerChanged;
Random rand = new Random();
Dictionary<string, Color> KeyColorPairs = new Dictionary<string, Color>();
public Color LinkSourceColor { get; set; }
public Color LinkTargetColor { get; set; }
public Color GetLinkSourceColor(SankeyLink link) {
return LinkSourceColor;
}
public Color GetLinkTargetColor(SankeyLink link) {
return LinkTargetColor;
}
public Color GetNodeColor(SankeyNode info) {
if (!KeyColorPairs.TryGetValue((string)info.Tag, out Color nodeColor)) {
nodeColor = GenerateColor();
KeyColorPairs.Add((string)info.Tag, nodeColor);
}
return nodeColor;
}
private Color GenerateColor() {
return Color.FromArgb(rand.Next(256), rand.Next(256), rand.Next(256));
}
}`

VB.NET

`Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs)
sankeyDiagramControl1.Colorizer = New MyColorizer With {
.LinkSourceColor = Color.Red,
.LinkTargetColor = Color.Yellow
}
End Sub

Public Class MyColorizer
Inherits ISankeyColorizer

Public Event ColorizerChanged As EventHandler
Private rand As Random = New Random()
Private KeyColorPairs As Dictionary(Of String, Color) = New Dictionary(Of String, Color)()
Public Property LinkSourceColor As Color
Public Property LinkTargetColor As Color

Public Function GetLinkSourceColor(ByVal link As SankeyLink) As Color
Return LinkSourceColor
End Function

Public Function GetLinkTargetColor(ByVal link As SankeyLink) As Color
Return LinkTargetColor
End Function

Public Function GetNodeColor(ByVal info As SankeyNode) As Color
Dim nodeColor As Color = Nothing

If Not KeyColorPairs.TryGetValue(CStr(info.Tag), nodeColor) Then
nodeColor = GenerateColor()
KeyColorPairs.Add(CStr(info.Tag), nodeColor)
End If

Return nodeColor
End Function

Private Function GenerateColor() As ColorReturn Color.FromArgb(rand.Next(256), rand.Next(256), rand.Next(256))End FunctionEnd Class`