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FlowChart.NET是一个通用的流程图控件，提供了用于创建或编辑图表的直观的用户交互模型。本教程展示在FlowChart.NET如何创建自定义节点类型。

1、定义一个自定义节点类

DiagramNode定义自定义节点类（本教程中使用的名称IconNode ）。

C#

public class IconNode : DiagramNode
{
}

Visual Basic

Public Class IconNode
    Inherits DiagramNode

End Class

2、定义一个静态构造函数

顶一个静态构造函数来初始化类的静态成员。

C#

static IconNode()
{
    defaultIcon = new Bitmap(48, 48);

    Graphics graphics = Graphics.FromImage(defaultIcon);
    Font font = new Font("Arial", 48, FontStyle.Bold, GraphicsUnit.Pixel);

    graphics.FillRectangle(Brushes.Transparent, 0, 0, 48, 48);
    graphics.DrawString("?", font, Brushes.Black, 0, 0);

    font.Dispose();
    graphics.Dispose();
} 

Visual Basic

Shared Sub New()

    defaultIcon = New Bitmap(48, 48)

    Dim graphics As Graphics = graphics.FromImage(defaultIcon)
    Dim font As Font = New Font("Arial", 48, FontStyle.Bold, GraphicsUnit.Pixel)

    graphics.FillRectangle(Brushes.Transparent, 0, 0, 48, 48)
    graphics.DrawString("?", font, Brushes.Black, 0, 0)

    font.Dispose()
    graphics.Dispose()

End Sub

3、定义一个公共的构造函数

定义构造函数来初始化实例成员。

C#

public IconNode(Diagram diagram) : base(diagram)
{
    icon = defaultIcon;
    label = "Label";

    format = new StringFormat();
    format.Alignment = StringAlignment.Center;
    format.LineAlignment = StringAlignment.Center;

    Bounds = new RectangleF(Bounds.Location, CalculateSize());
}

Visual Basic

Sub New(ByVal diagram As Diagram)

    MyBase.New(diagram)

    fIcon = defaultIcon
    fLabel = "Label"

    format = New StringFormat
    format.Alignment = StringAlignment.Center
    format.LineAlignment = StringAlignment.Center

    Bounds = New RectangleF(Bounds.Location, CalculateSize())

End Sub