Imports Autodesk.AutoCAD.ApplicationServices
Imports Autodesk.AutoCAD.DatabaseServices
Imports Autodesk.AutoCAD.EditorInput
Imports Autodesk.AutoCAD.Geometry
Imports Autodesk.AutoCAD.Runtime
Imports Autodesk.AutoCAD.GraphicsInterface
<Assembly: CommandClass(GetType(OverRule_图名.图名_Overule))> 
Namespace OverRule_图名
    Public Class 图名_Overule
        <CommandMethod("TcTuMingStart")> _
        Public Sub TcTuMingStart()
            Dim NewRule As New TuMing_OverRule()
            StartOverRule(RXClass.GetClass(GetType(DBText)), NewRule)
        End Sub
        <CommandMethod("TcTuMingEnd")> _
        Public Sub TcTuMingEnd()
            EndOverRule()
        End Sub
        Public Shared Sub StartOverRule(ByVal CADClass As RXClass, ByVal Rule As Overrule)
            Overrule.AddOverrule(CADClass, Rule, False)
            Overrule.Overruling = True
        End Sub
        Public Shared Sub EndOverRule()
            Overrule.Overruling = False
        End Sub
    End Class
    Public Class TuMing_OverRule
        Inherits DrawableOverrule
        Public Overrides Function WorldDraw(ByVal Drawable As Drawable, ByVal WD As WorldDraw) As Boolean
            On Error Resume Next
            '如果为单行文字，则进行规则重定义 
            If TypeOf Drawable Is DBText Then
                Dim DB As DBText = DirectCast(Drawable, DBText)
                If Not DB.Id.IsNull Then
                    If DB.Layer = "图名" Then '文字在"图名"图层上
                        Dim H As Double = DB.Height
                        Dim Xmin As Double = DB.GeometricExtents.MinPoint.X
                        Dim Xmax As Double = DB.GeometricExtents.MaxPoint.X
                        Dim Y As Double = DB.GeometricExtents.MinPoint.Y
                        Dim P1 As Point2d = New Point2d(Xmin, Y - H / 5)
                        Dim P2 As Point2d = New Point2d(Xmax, Y - H / 5)
                        Dim PL1 As Autodesk.AutoCAD.DatabaseServices.Polyline = New Autodesk.AutoCAD.DatabaseServices.Polyline
                        Dim PL2 As Autodesk.AutoCAD.DatabaseServices.Polyline = New Autodesk.AutoCAD.DatabaseServices.Polyline
                        PL1.AddVertexAt(0, P1, 0, H / 6, H / 6)
                        PL1.AddVertexAt(1, P2, 0, H / 6, H / 6)
                        P1 = New Point2d(Xmin, Y - 2 * H / 5)
                        P2 = New Point2d(Xmax, Y - 2 * H / 5)
                        PL2.AddVertexAt(0, P1, 0, 0, 0)
                        PL2.AddVertexAt(1, P2, 0, 0, 0)
                        PL1.WorldDraw(WD)
                        PL1.Dispose()
                        PL2.WorldDraw(WD)
                        PL2.Dispose()
                        MyBase.WorldDraw(DB, WD) '这句可以保留原对象
                    Else
                        MyBase.WorldDraw(DB, WD)
                    End If
                End If
            End If
            If Err.Number > 0 Then MsgBox(Err.Description)
            Return True
        End Function
    End Class
End Namespace