打开和关闭图层 （.NET）

关闭的图层随图形一起再生，但不显示或打印。通过关闭图层，可以避免每次解冻图层时重新生成图形。当您打开已关闭的图层时，AutoCAD 会重新绘制该图层上的对象。

在对象上使用表示要打开或关闭的图层的属性。如果输入值 ，则图层将关闭。如果输入值 ，则图层处于打开状态。IsOffLayerTableRecordTRUEFALSE

关闭图层

本示例创建一个新图层并将其关闭，然后向该图层添加一个圆圈，使该圆圈不再可见。

Imports Autodesk.AutoCAD.Runtime
Imports Autodesk.AutoCAD.ApplicationServices
Imports Autodesk.AutoCAD.DatabaseServices
Imports Autodesk.AutoCAD.Geometry
 
<CommandMethod("TurnLayerOff")> _
Public Sub TurnLayerOff()
    '' Get the current document and 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 Layer table for read
        Dim acLyrTbl As LayerTable
        acLyrTbl = acTrans.GetObject(acCurDb.LayerTableId, _
                                     OpenMode.ForRead)

        Dim sLayerName As String = "ABC"

        If acLyrTbl.Has(sLayerName) = False Then
            Using acLyrTblRec As LayerTableRecord = New LayerTableRecord()

                '' Assign the layer a name
                acLyrTblRec.Name = sLayerName

                '' Turn the layer off
                acLyrTblRec.IsOff = True

                '' Upgrade the Layer table for write
                acTrans.GetObject(acCurDb.LayerTableId, OpenMode.ForWrite)

                '' Append the new layer to the Layer table and the transaction
                acLyrTbl.Add(acLyrTblRec)
                acTrans.AddNewlyCreatedDBObject(acLyrTblRec, True)
            End Using
        Else
            Dim acLyrTblRec As LayerTableRecord = acTrans.GetObject(acLyrTbl(sLayerName), _
                                                                    OpenMode.ForWrite)

            '' Turn the layer off
            acLyrTblRec.IsOff = True
        End If

        '' 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 a circle object
        Using acCirc As Circle = New Circle()
            acCirc.Center = New Point3d(2, 2, 0)
            acCirc.Radius = 1
            acCirc.Layer = sLayerName

            acBlkTblRec.AppendEntity(acCirc)
            acTrans.AddNewlyCreatedDBObject(acCirc, True)
        End Using

        '' Save 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("TurnLayerOff")]
public static void TurnLayerOff()
{
    // Get the current document and database
    Document acDoc = Application.DocumentManager.MdiActiveDocument;
    Database acCurDb = acDoc.Database;

    // Start a transaction
    using (Transaction acTrans = acCurDb.TransactionManager.StartTransaction())
    {
        // Open the Layer table for read
        LayerTable acLyrTbl;
        acLyrTbl = acTrans.GetObject(acCurDb.LayerTableId,
                                        OpenMode.ForRead) as LayerTable;

        string sLayerName = "ABC";

        if (acLyrTbl.Has(sLayerName) == false)
        {
            using (LayerTableRecord acLyrTblRec = new LayerTableRecord())
            {
                // Assign the layer a name
                acLyrTblRec.Name = sLayerName;

                // Turn the layer off
                acLyrTblRec.IsOff = true;

                // Upgrade the Layer table for write
                acTrans.GetObject(acCurDb.LayerTableId, OpenMode.ForWrite);

                // Append the new layer to the Layer table and the transaction
                acLyrTbl.Add(acLyrTblRec);
                acTrans.AddNewlyCreatedDBObject(acLyrTblRec, true);
            }
        }
        else
        {
            LayerTableRecord acLyrTblRec = acTrans.GetObject(acLyrTbl[sLayerName],
                                            OpenMode.ForWrite) as LayerTableRecord;

            // Turn the layer off
            acLyrTblRec.IsOff = true;
        }

        // 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 a circle object
        using (Circle acCirc = new Circle())
        {
            acCirc.Center = new Point3d(2, 2, 0);
            acCirc.Radius = 1;
            acCirc.Layer = sLayerName;

            acBlkTblRec.AppendEntity(acCirc);
            acTrans.AddNewlyCreatedDBObject(acCirc, true);
        }

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

Sub TurnLayerOff()
    ' Create a new layer called "ABC"
    Dim layerObj As AcadLayer
    Set layerObj = ThisDrawing.Layers.Add("ABC")
 
    ' Turn off layer "ABC"
    layerObj.LayerOn = False
 
    ' Create a circle
    Dim circleObj As AcadCircle
    Dim center(0 To 2) As Double
    Dim radius As Double
    center(0) = 2: center(1) = 2: center(2) = 0
    radius = 1
    Set circleObj = ThisDrawing.ModelSpace. _
                                  AddCircle(center, radius)
 
    ' Assign the circle to the "ABC" layer
    circleObj.Layer = "ABC"
    circleObj.Update
 
    ThisDrawing.Regen acActiveViewport
End Sub