AMindMap需要一个Line，用以连接父ANode和子ANode，
简单说，就是一头大一头小的线，Wpf自带的Line是没这个功能。
Path可以画，不过，我的想法仍旧是绑定。那只能自己做咯。
| 图例 |
| 正文 |
既然Line,Rectangle等都是继承自Shape的,直接新建一个类继承自Sharp.
1 Public Class ALine
2 Inherits Shape
3
4 Protected Overrides ReadOnly Property DefiningGeometry As System.Windows.Media.Geometry
5 Get
6
7 End Get
8 End Property
9 End Class
10
继承完Shape，ALine中自动添加了一个需要重写的只读属性，从字面上就可以理解
为自定义shape的内容了。返回一个Geometry，那岂不是嗯嗯嗯？
| ALine的属性 |
一头大一头小的Line也是Line，那就要有两个端点，并且，端点的数值是需要被
绑定的，大声一起说，“DependencyProperty”
1
2 #Region " X1 DependencyProperty "
3 ''' <summary>
4 ''' PropertyComment
5 ''' </summary>
6 ''' <remarks></remarks>
7 Public Shared ReadOnly X1Property As DependencyProperty = _
8 DependencyProperty.Register(
9 "X1", GetType(Double), GetType(ALine), New FrameworkPropertyMetadata( _
10 0.0, FrameworkPropertyMetadataOptions.AffectsMeasure))
11
12 Public Property X1() As Double
13 Get
14 Return GetValue(X1Property)
15 End Get
16 Set(ByVal Value As Double)
17 SetValue(X1Property, Value)
18 End Set
19 End Property
20 #End Region
21
22 #Region " Y1 DependencyProperty "
23 ''' <summary>
24 ''' PropertyComment
25 ''' </summary>
26 ''' <remarks></remarks>
27 Public Shared ReadOnly Y1Property As DependencyProperty = _
28 DependencyProperty.Register(
29 "Y1", GetType(Double), GetType(ALine), New FrameworkPropertyMetadata( _
30 0.0, FrameworkPropertyMetadataOptions.AffectsMeasure))
31
32 Public Property Y1() As Double
33 Get
34 Return GetValue(Y1Property)
35 End Get
36 Set(ByVal Value As Double)
37 SetValue(Y1Property, Value)
38 End Set
39 End Property
40
41 #End Region
42
43 #Region " X2 DependencyProperty "
44 ''' <summary>
45 ''' PropertyComment
46 ''' </summary>
47 ''' <remarks></remarks>
48 Public Shared ReadOnly X2Property As DependencyProperty = _
49 DependencyProperty.Register(
50 "X2", GetType(Double), GetType(ALine), New FrameworkPropertyMetadata( _
51 0.0, FrameworkPropertyMetadataOptions.AffectsMeasure))
52
53 Public Property X2() As Double
54 Get
55 Return GetValue(X2Property)
56 End Get
57 Set(ByVal Value As Double)
58 SetValue(X2Property, Value)
59 End Set
60 End Property
61
62 #End Region
63
64 #Region " Y2 DependencyProperty "
65 ''' <summary>
66 ''' PropertyComment
67 ''' </summary>
68 ''' <remarks></remarks>
69 Public Shared ReadOnly Y2Property As DependencyProperty = _
70 DependencyProperty.Register(
71 "Y2", GetType(Double), GetType(ALine), New FrameworkPropertyMetadata( _
72 0.0, FrameworkPropertyMetadataOptions.AffectsMeasure))
73
74 Public Property Y2() As Double
75 Get
76 Return GetValue(Y2Property)
77 End Get
78 Set(ByVal Value As Double)
79 SetValue(Y2Property, Value)
80 End Set
81 End Property
82
83 #End Region
84
85 #Region " TailWidth DependencyProperty "
86 ''' <summary>
87 ''' PropertyComment
88 ''' </summary>
89 ''' <remarks></remarks>
90 Public Shared ReadOnly TailWidthProperty As DependencyProperty = _
91 DependencyProperty.Register(
92 "TailWidth", GetType(Double), GetType(ALine), New FrameworkPropertyMetadata( _
93 3.0, FrameworkPropertyMetadataOptions.AffectsMeasure))
94 Public Property TailWidth() As Double
95 Get
96 Return GetValue(TailWidthProperty)
97 End Get
98 Set(ByVal Value As Double)
99 SetValue(TailWidthProperty, Value)
100 End Set
101 End Property
102
103 #End Region
这里定义了X1,Y1,X2,Y2,TailWidth,这些属性足够说明，线的位置和尾部粗细。
| ALine的内容 |
一个楔形是怎么画的呢？这只是一个几何问题，还是画一张图说明吧。
Sorry哈，反正就是Atan，sin，cos一通算，画图太费劲了，我就歇了哈。
| 代码 强制重载的DefiningGeometry |
1
2 Protected Overrides ReadOnly Property DefiningGeometry As System.Windows.Media.Geometry
3 Get
4 Dim mGeometry As New StreamGeometry
5 mGeometry.FillRule = FillRule.EvenOdd
6
7 Using context As StreamGeometryContext = mGeometry.Open
8 DrawLineGeometry(context)
9 End Using
10 mGeometry.Freeze()
11 Return mGeometry
12 End Get
13 End Property
14
15 Private Sub DrawLineGeometry(ByVal context As StreamGeometryContext)
16 Dim theta As Double = Math.Atan2(Y1 - Y2, X1 - X2)
17 Dim sint As Double = Math.Sin(theta)
18 Dim cost As Double = Math.Cos(theta)
19 Dim pt1 As Point = New Point(X2, Y2)
20 Dim pt2 As Point = New Point(X1 - TailWidth * sint, Y1 + TailWidth * cost)
21 Dim pt3 As Point = New Point(X1 + TailWidth * sint, Y1 - TailWidth * cost)
22 context.BeginFigure(pt1, True, True)
23 context.LineTo(pt2, True, True)
24 context.LineTo(pt3, True, True)
25 End Sub
| 实例 |
在一个空白窗口中，像使用Line一样。
1 <local:ALine X1="10" Y1="10" X2="100" Y2="100" TailWidth="10"
2 Fill="LightBlue"
3 Canvas.Left="93" Canvas.Top="76"
4 >
5 </local:ALine>
就这个效果
我不得不说，这个思路是在网上找到的，既然找到了，给大家分享一下，是一件好事儿。