autocad .net 获取块的外轮廓

在AutoCAD .NET中，可以使用以下代码获取块的外轮廓：

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

public void GetBlockOutline()
{
    Document doc = Application.DocumentManager.MdiActiveDocument;
    Database db = doc.Database;
    Editor ed = doc.Editor;

    // 提示用户选择块
    PromptEntityOptions peo = new PromptEntityOptions("请选择块：");
    peo.SetRejectMessage("请选择有效的块！");
    peo.AddAllowedClass(typeof(BlockReference), true);
    PromptEntityResult per = ed.GetEntity(peo);

    if (per.Status == PromptStatus.OK)
    {
        using (Transaction tr = db.TransactionManager.StartTransaction())
        {
            BlockReference blockRef = tr.GetObject(per.ObjectId, OpenMode.ForRead) as BlockReference;
            if (blockRef != null)
            {
                // 获取块的外边界
                Extents3d blockExtents = blockRef.GeometricExtents;

                // 输出外边界的最小点和最大点坐标
                Point3d minPoint = blockExtents.MinPoint;
                Point3d maxPoint = blockExtents.MaxPoint;

                ed.WriteMessage("块的外轮廓最小点坐标：{0}\n", minPoint);
                ed.WriteMessage("块的外轮廓最大点坐标：{0}\n", maxPoint);
            }

            tr.Commit();
        }
    }
}

请注意，上述代码需要在AutoCAD .NET开发环境中运行，并且需要引用`Autodesk.AutoCAD.ApplicationServices`、`Autodesk.AutoCAD.DatabaseServices`、`Autodesk.AutoCAD.EditorInput`和`Autodesk.AutoCAD.Geometry`命名空间。