AutoCAD Managed .NET API 允许您使用使用. NET 4.0 引入的动态语言运行时 (DLR)。
使用 DLR 可以直接访问对象, 而无需:
- 打开一个对象进行读取或写入, 然后在完成后关闭该对象。
- 利用事务提交所做的更改。
在使用 DLR 时获得对象的 ObjectId 后, 可以直接访问对象的属性和方法。获得 ObjectId 后, 可以将 ObjectId 分配给数据类型的变量:
- Object in VB.NET
- dynamic in C#
获取 ObjectId 因对象保存到数据库的方式而异。对于存储在表或字典中的对象, 可以通过以下方式访问其 ObjectId:
- 使用 ObjectId 的 item 方法访问集合中的元素。
- 创建对表或字典的 ObjectId 的引用并将其分配给变量, 然后访问数组的元素。
下面的示例代码显示了用于访问存储在与 DLR 的表或字典中的对象的两个选项:
// Item method
dynamic acCurDb = HostApplicationServices.WorkingDatabase;
dynamic acMSpace = acCurDb.BlockTableId.Item(BlockTableRecord.ModelSpace);
// Reference an element directly from a collection
dynamic acCurDb = HostApplicationServices.WorkingDatabase;
dynamic acBlkTbl = acCurDb.BlockTableId;
dynamic acMSpace = acBlkTbl[BlockTableRecord.ModelSpace];
重要提示: 在使用 DLR 和 C# 时, 您需要引用 Microsoft.CSharp 库。
使用 GetEnumerator 方法
在将 GetEnumerator 方法与 DLR 一起使用时, 需要在使用完枚举器对象后显式释放该对象。下面的示例演示如何在完成枚举器时对其进行处置。
dynamic acCurDb = HostApplicationServices.WorkingDatabase;
var acLtypeTbl = acCurDb.LinetypeTableId;
var acTblEnum = acLtypeTbl.GetEnumerator();
...
acTblEnum.Dispose();
使用 LINQ 查询
您可以利用 LINQ 查询在使用 DLR 的图形中查询表或字典的内容。下面的示例演示如何使用 LINQ 查询来查询哪些图层在当前图形中具有分配给它们的某些状态。
[CommandMethod("LINQ")]
public static void LINQExample()
{
dynamic db = HostApplicationServices.WorkingDatabase;
dynamic doc = Application.DocumentManager.MdiActiveDocument;
var layers = db.LayerTableId;
for (int i = 0; i < 2; i++)
{
var newrec = layers.Add(new LayerTableRecord());
newrec.Name = "Layer" + i.ToString();
if (i == 0)
newrec.IsFrozen = true;
if (i == 1)
newrec.IsOff = true;
}
var OffLayers = from l in (IEnumerable<dynamic>)layers
where l.IsOff
select l;
doc.Editor.WriteMessage("\nLayers Turned Off:");
foreach (dynamic rec in OffLayers)
doc.Editor.WriteMessage("\n - " + rec.Name);
var frozenOrOffNames = from l in (IEnumerable<dynamic>)layers
where l.IsFrozen == true || l.IsOff == true
select l;
doc.Editor.WriteMessage("\nLayers Frozen or Turned Off:");
foreach (dynamic rec in frozenOrOffNames)
doc.Editor.WriteMessage("\n - " + rec.Name);
}
示例代码
此页上的示例代码使用以下名称空间:
Autodesk.AutoCAD.Runtime
Autodesk.AutoCAD.ApplicationServices
Autodesk.AutoCAD.DatabaseServices
Autodesk.AutoCAD.Colors
Autodesk.AutoCAD.Geometry
下面的示例代码演示使用和不适用 DLR 如何将直线添加到当前空间。
[CommandMethod("ADDLINE")]
public static void AddLine()
{
// Get the current database
Database acCurDb = HostApplicationServices.WorkingDatabase;
// 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 a line that starts at 5,5 and ends at 12,3
using (Line acLine = new Line(new Point3d(5, 5, 0),
new Point3d(12, 3, 0)))
{
// Add the new object to the block table record and the transaction
acBlkTblRec.AppendEntity(acLine);
acTrans.AddNewlyCreatedDBObject(acLine, true);
}
// Save the new object to the database
acTrans.Commit();
}
}
C# with Dynamic Language Runtime (DLR)
[CommandMethod("ADDLINE")]
public static void AddLine()
{
// Get the current database
dynamic acCurDb = HostApplicationServices.WorkingDatabase;
// Create a dynamic reference to model or paper space
dynamic acSpace = acCurDb.CurrentSpaceId;
// Create a line that starts at 5,5 and ends at 12,3
dynamic acLine = new Line(new Point3d(5, 5, 0),
new Point3d(12, 3, 0));
// Add the new object to the current space
acSpace.AppendEntity(acLine);
}
下面的示例代码演示使用和不使用 DLR 如何将层添加到当前数据库中。
[CommandMethod("ADDLAYER")]
public static void AddLayer()
{
// Get the current database
Database acCurDb = HostApplicationServices.WorkingDatabase;
using (Transaction acTrans = acCurDb.TransactionManager.StartTransaction())
{
// Returns the layer table for the current database
LayerTable acLyrTbl;
acLyrTbl = acTrans.GetObject(acCurDb.LayerTableId,
OpenMode.ForRead) as LayerTable;
// Check to see if MyLayer exists in the Layer table
if (acLyrTbl.Has("MyLayer") != true)
{
// Open the Layer Table for write
acTrans.GetObject(acCurDb.LayerTableId, OpenMode.ForWrite);
// Create a new layer named "MyLayer"
using (LayerTableRecord acLyrTblRec = new LayerTableRecord())
{
acLyrTblRec.Name = "MyLayer";
// Assign the ACI color 3 to the new layer
Color acClr = Color.FromColorIndex(ColorMethod.ByAci, 3);
acLyrTblRec.Color = acClr;
// Add the new layer table record to the layer table and the transaction
acLyrTbl.Add(acLyrTblRec);
acTrans.AddNewlyCreatedDBObject(acLyrTblRec, true);
}
// Commit the changes
acTrans.Commit();
}
// Dispose of the transaction
}
}
C# with Dynamic Language Runtime (DLR)
[CommandMethod("ADDLAYER")]
public static void AddLayer()
{
// Get the current database
dynamic acCurDb = HostApplicationServices.WorkingDatabase;
dynamic acLyrTbl = acCurDb.LayerTableId;
// Check to see if MyLayer exists in the Layer table
if (acLyrTbl.Has("MyLayer") != true)
{
// Create a new layer named "MyLayer"
dynamic acLyrTblRec = new LayerTableRecord();
acLyrTblRec.Name = "MyLayer";
// Assign the ACI color 3 to the new layer
dynamic acClr = Color.FromColorIndex(ColorMethod.ByAci, 3);
acLyrTblRec.Color = acClr;
// Add the new layer table record to the layer table
acLyrTbl.Add(acLyrTblRec);
}
}
下面演示了使用和不使用 DLR 如何逐步通过并列出当前空间中的所有对象。
[CommandMethod("LISTOBJECTS")]
public static void ListObjects()
{
// Get the current document and database
Document acDoc = Application.DocumentManager.MdiActiveDocument;
Database acCurDb = HostApplicationServices.WorkingDatabase;
using (Transaction acTrans = acCurDb.TransactionManager.StartTransaction())
{
// Open the Block table record Model space for write
BlockTableRecord acSpace;
acSpace = acTrans.GetObject(acCurDb.CurrentSpaceId,
OpenMode.ForRead) as BlockTableRecord;
// Step through the current space
foreach (ObjectId objId in acSpace)
{
// Display the class and current layer of the object
Entity acEnt = (Entity)acTrans.GetObject(objId, OpenMode.ForRead);
acDoc.Editor.WriteMessage("\nObject Class: " + acEnt.GetRXClass().Name +
"\nCurrent Layer: " + acEnt.Layer +
"\n");
}
acTrans.Commit();
}
}
C# with Dynamic Language Runtime (DLR)
[CommandMethod("LISTOBJECTS")]
public static void ListObjects()
{
// Get the current document and database
dynamic acDoc = Application.DocumentManager.MdiActiveDocument;
dynamic acCurDb = HostApplicationServices.WorkingDatabase;
// Create a dynamic reference to model or paper space
dynamic acSpace = acCurDb.CurrentSpaceId;
// Step through the current space
foreach (dynamic acEnt in acSpace)
{
// Display the class and current layer of the object
acDoc.Editor.WriteMessage("\nObject Class: " + acEnt.GetRXClass().Name +
"\nCurrent Layer: " + acEnt.Layer +
"\n");
}
}