使用 AutoCAD 的 .NET API 编写自定义插件。

例如，以下是一个简单的插件示例，用于标记选定的对象的长度和角度：

using Autodesk.AutoCAD.ApplicationServices;
using Autodesk.AutoCAD.DatabaseServices;
using Autodesk.AutoCAD.EditorInput;
using Autodesk.AutoCAD.Geometry;
using Autodesk.AutoCAD.Runtime;

namespace MyPluginNamespace
{
    public class MyPluginClass
    {
        [CommandMethod("MyLabelPlugin")]
        public static void LabelSelectedObjects()
        {
            Document doc = Application.DocumentManager.MdiActiveDocument;
            Editor editor = doc.Editor;

            // 选择对象
            PromptSelectionResult selectionResult = editor.GetSelection();
            if (selectionResult.Status != PromptStatus.OK)
                return;

            using (Transaction trx = doc.TransactionManager.StartTransaction())
            {
                BlockTableRecord btr = (BlockTableRecord)trx.GetObject(SymbolUtilityServices.GetBlockModelSpaceId(doc.Database), OpenMode.ForWrite);

                // 标注选定的对象
                foreach (SelectedObject selObj in selectionResult.Value)
                {
                    Entity ent = trx.GetObject(selObj.ObjectId, OpenMode.ForRead) as Entity;
                    if (ent != null)
                    {
                        double len = ent.Length;
                        double angle = ent.GetAngleTo(new Vector3d(1, 0, 0));

                        DBText lenText = new DBText();
                        lenText.TextString = string.Format("Len={0:F2}", len);
                        lenText.Position = ent.GeometricExtents.MinPoint;
                        btr.AppendEntity(lenText);
                        trx.AddNewlyCreatedDBObject(lenText, true);

                        DBText angleText = new DBText();
                        angleText.TextString = string.Format("Angle={0:F2}", angle);
                        angleText.Position = ent.GeometricExtents.MaxPoint;
                        btr.AppendEntity(angleText);
                        trx.AddNewlyCreatedDBObject(angleText, true);
                    }
                }

                // 提交事务
                trx.Commit();
            }
        }
    }
}

要使用此插件，请打开 AutoCAD，加载 .NET 程序集，然后输入命令 MyLabelPlugin。选择要标注的对象，插件将在每个对象的