创建引导线 （.NET）

可以从图形中的任何点或要素创建引出线并控制其外观。引线可以是直线段或平滑样条曲线。引线颜色由当前尺寸线颜色控制。引线比例由活动标注样式中的整体尺寸刻度集控制。箭头的类型和大小（如果存在）由活动样式中定义的箭头控制。

一条称为钩线的小线通常将注释连接到引线。如果最后一个引出线段与水平线成大于 15 度的角度，则钩线将显示为多线文本和要素控制框。钩线是单个箭头的长度。如果引线没有注释，则它没有钩线。

您可以通过创建领导者对象的实例来创建领导者。创建 Leader 对象的实例时，其构造函数不接受任何参数。该方法用于定义所创建引线的位置和长度。AppendVertex

创建引导线

本示例在模型空间中创建一条引导线。没有与引出线关联的注释。

Imports Autodesk.AutoCAD.Runtime
Imports Autodesk.AutoCAD.ApplicationServices
Imports Autodesk.AutoCAD.DatabaseServices
Imports Autodesk.AutoCAD.Geometry
 
<CommandMethod("CreateLeader")> _
Public Sub CreateLeader()
    '' Get the current database
    Dim acDoc As Document = Application.DocumentManager.MdiActiveDocument
    Dim acCurDb As Database = acDoc.Database

    '' Start a transaction
    Using acTrans As Transaction = acCurDb.TransactionManager.StartTransaction()

        '' Open the Block table for read
        Dim acBlkTbl As BlockTable
        acBlkTbl = acTrans.GetObject(acCurDb.BlockTableId, _
                                     OpenMode.ForRead)

        '' Open the Block table record Model space for write
        Dim acBlkTblRec As BlockTableRecord
        acBlkTblRec = acTrans.GetObject(acBlkTbl(BlockTableRecord.ModelSpace), _
                                        OpenMode.ForWrite)

        '' Create the leader
        Using acLdr As Leader = New Leader()
            acLdr.AppendVertex(New Point3d(0, 0, 0))
            acLdr.AppendVertex(New Point3d(4, 4, 0))
            acLdr.AppendVertex(New Point3d(4, 5, 0))
            acLdr.HasArrowHead = True

            '' Add the new object to Model space and the transaction
            acBlkTblRec.AppendEntity(acLdr)
            acTrans.AddNewlyCreatedDBObject(acLdr, True)
        End Using

        '' Commit the changes and dispose of the transaction
        acTrans.Commit()
    End Using
End Sub

using Autodesk.AutoCAD.Runtime;
using Autodesk.AutoCAD.ApplicationServices;
using Autodesk.AutoCAD.DatabaseServices;
using Autodesk.AutoCAD.Geometry;
 
[CommandMethod("CreateLeader")]
public static void CreateLeader()
{
    // Get the current database
    Document acDoc = Application.DocumentManager.MdiActiveDocument;
    Database acCurDb = acDoc.Database;

    // Start a transaction
    using (Transaction acTrans = acCurDb.TransactionManager.StartTransaction())
    {
        // Open the Block table for read
        BlockTable acBlkTbl;
        acBlkTbl = acTrans.GetObject(acCurDb.BlockTableId,
                                        OpenMode.ForRead) as BlockTable;

        // Open the Block table record Model space for write
        BlockTableRecord acBlkTblRec;
        acBlkTblRec = acTrans.GetObject(acBlkTbl[BlockTableRecord.ModelSpace],
                                        OpenMode.ForWrite) as BlockTableRecord;

        // Create the leader
        using (Leader acLdr = new Leader())
        {
            acLdr.AppendVertex(new Point3d(0, 0, 0));
            acLdr.AppendVertex(new Point3d(4, 4, 0));
            acLdr.AppendVertex(new Point3d(4, 5, 0));
            acLdr.HasArrowHead = true;

            // Add the new object to Model space and the transaction
            acBlkTblRec.AppendEntity(acLdr);
            acTrans.AddNewlyCreatedDBObject(acLdr, true);
        }

        // Commit the changes and dispose of the transaction
        acTrans.Commit();
    }
}

Sub CreateLeader()
    Dim leaderObj As AcadLeader
    Dim points(0 To 8) As Double
    Dim leaderType As Integer
    Dim annotationObject As AcadObject
 
    points(0) = 0: points(1) = 0: points(2) = 0
    points(3) = 4: points(4) = 4: points(5) = 0
    points(6) = 4: points(7) = 5: points(8) = 0
    leaderType = acLineWithArrow
    Set annotationObject = Nothing
 
    ' Create the leader object in model space
    Set leaderObj = ThisDrawing.ModelSpace. _
                        AddLeader(points, annotationObject, leaderType)
 
    ZoomAll
End Sub