03-05 创建和编辑AutoCAD实体（五） 使用图层、颜色和线型（1）使用图层（1-6）

1.6、Lock and Unlock Layers锁定和解锁图层

You cannot edit objects on a locked layer; however, they are still visible if the layer is on and thawed. You can make a locked layer current and you can add objects to it. You can freeze and turn off locked layers and change their associated
colors and linetypes.
我们不能编辑已锁定图层上的对象，不过，如果已锁定图层是打开的并且是解冻的，那么图层上的对象仍然是可见的。我们可以将已锁定图层设为当前图层并往上添加对象，我们还可以冻结、关闭已锁定图层以及修改其关联的颜色和线型等。
Use the IsLocked property to lock or unlock a layer. If you input a value of TRUE, the layer is locked. If you input a value of FALSE, the layer is unlocked.

使用IsLocked属性来锁定或解锁图层。IsLocked属性值为TRUE则锁定图层，IsLocked属性值为FALSE则解锁图层。

Lock a layer 锁定图层

This example creates a new layer called “ABC” and then locks the layer.

本例创建一个名为“ABC”的新图层，然后将其锁定。

VB.NET
Imports Autodesk.AutoCAD.Runtime
Imports Autodesk.AutoCAD.ApplicationServices
Imports Autodesk.AutoCAD.DatabaseServices

<CommandMethod("LockLayer")> _
Public Sub LockLayer()
'' 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"
Dim acLyrTblRec As LayerTableRecord

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

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

'' Upgrade the Layer table for write
acLyrTbl.UpgradeOpen()

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

'' Lock the layer
acLyrTblRec.IsLocked = True

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

C#
using Autodesk.AutoCAD.Runtime;
using Autodesk.AutoCAD.ApplicationServices;
using Autodesk.AutoCAD.DatabaseServices;

[CommandMethod("LockLayer")]
public static void LockLayer()
{
// Get the current document and database获取当前文档和数据库
Document acDoc = Application.DocumentManager.MdiActiveDocument;
Database acCurDb = acDoc.Database;

// Start a transaction启动事务
using (Transaction acTrans = acCurDb.TransactionManager.StartTransaction())
{
// Open the Layer table for read以读打开图层表
LayerTable acLyrTbl;
acLyrTbl = acTrans.GetObject(acCurDb.LayerTableId, OpenMode.ForRead) as LayerTable;

string sLayerName = "ABC";
LayerTableRecord acLyrTblRec;

if (acLyrTbl.Has(sLayerName) == false)
{
acLyrTblRec = new LayerTableRecord();

// Assign the layer a name给图层名称赋值
acLyrTblRec.Name = sLayerName;

// Upgrade the Layer table for write升级打开图层表
acLyrTbl.UpgradeOpen();

// Append the new layer to the Layer table and the transaction追加新图层到图层表，追加事务记录
acLyrTbl.Add(acLyrTblRec);
acTrans.AddNewlyCreatedDBObject(acLyrTblRec, true);
}
else
{
acLyrTblRec = acTrans.GetObject(acLyrTbl[sLayerName],
OpenMode.ForWrite) as LayerTableRecord;
}

// Lock the layer锁定图层
acLyrTblRec.IsLocked = true;

// Save the changes and dispose of the transaction提交修改、关闭事务
acTrans.Commit();
}
}

VBA/ActiveX Code Reference
Sub LockLayer()
' Create a new layer called "ABC"
Dim layerObj As AcadLayer
Set layerObj = ThisDrawing.Layers.Add("ABC")

' Lock layer "ABC"
layerObj.Lock = True
End Sub