cad二次开发.net怎样设置MText的附着点为中心点

您可以使用以下代码将MText的附着点设置为中心点：

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

namespace YourNamespace
{
    public class YourClass
    {
        [CommandMethod("SetMTextAttachment")]
        public void SetMTextAttachment()
        {
            Document doc = Application.DocumentManager.MdiActiveDocument;
            Database db = doc.Database;
            Editor ed = doc.Editor;

            // Ask the user to select an MText object
            PromptEntityOptions peo = new PromptEntityOptions("\nSelect MText object: ");
            peo.SetRejectMessage("\nSelected entity is not an MText object.");
            peo.AddAllowedClass(typeof(MText), true);
            PromptEntityResult per = ed.GetEntity(peo);
            if (per.Status != PromptStatus.OK) return;

            // Open the MText object for write
            using (Transaction tr = db.TransactionManager.StartTransaction())
            {
                MText mtext = tr.GetObject(per.ObjectId, OpenMode.ForWrite) as MText;

                // Set the attachment point to the center
                mtext.Attachment = AttachmentPoint.MiddleCenter;

                // Update the MText object
                mtext.Update();

                // Commit the transaction
                tr.Commit();
            }

            ed.WriteMessage("\nMText attachment point set to center.");
        }
    }
}

将此代码添加到您的.NET二次开发项目中，并将其编译为DLL文件。然后，在AutoCAD中加载该DLL文件，并运行命令“SetMTextAttachment”即可。选择要更改的MText对象后，将其附着点设置为中心点。