使用C#语言在visual studio 平台上写一段CAD二次开发.net代码用于生产类库dll文件，CAD加载dll文件后，须由用户在CAD界面选定2根直线，输入2根直线等分数量N，计算直线N等分后N+1个等分点坐标，并由2条直线等分点成对生成N+1条直线，直线需显示在CAD界面

好的，根据您的要求，我可以给您提供一段C#代码，用于实现CAD二次开发.net，生成类库dll文件，实现选定2根直线，输入等分数量N，计算直线N等分后N+1个等分点坐标，并由2条直线等分点成对生成N+1条直线，直线在CAD界面上显示的功能。代码如下：

// 引入AutoCAD COM组件
using Autodesk.AutoCAD.Runtime;
using Autodesk.AutoCAD.ApplicationServices;
using Autodesk.AutoCAD.DatabaseServices;
using Autodesk.AutoCAD.Geometry;

namespace MyCADPlugin
{
    public class MyCommands
    {
        [CommandMethod("MyLineDivide")]
        public static void LineDivide()
        {
            // 获取当前文档和数据库
            Document doc = Application.DocumentManager.MdiActiveDocument;
            Database db = doc.Database;

            // 选择第一条直线
            PromptEntityOptions peo1 = new PromptEntityOptions("请选择第一根直线：");
            peo1.SetRejectMessage("请选择直线！");
            peo1.AddAllowedClass(typeof(Line), true);
            PromptEntityResult per1 = doc.Editor.GetEntity(peo1);
            if (per1.Status != PromptStatus.OK) return;
            ObjectId lineId1 = per1.ObjectId;

            // 选择第二条直线
            PromptEntityOptions peo2 = new PromptEntityOptions("请选择第二根直线：");
            peo2.SetRejectMessage("请选择直线！");
            peo2.AddAllowedClass(typeof(Line), true);
            PromptEntityResult per2 = doc.Editor.GetEntity(peo2);
            if (per2.Status != PromptStatus.OK) return;
            ObjectId lineId2 = per2.ObjectId;

            // 输入等分数量
            PromptIntegerOptions pio = new PromptIntegerOptions("请输入等分数量：");
            pio.AllowNegative = false;
            pio.AllowZero = false;
            PromptIntegerResult pir = doc.Editor.GetInteger(pio);
            if (pir.Status != PromptStatus.OK) return;
            int divideNum = pir.Value;

            // 获取直线1和直线2的起点和终点坐标
            Point3d startPoint1, endPoint1, startPoint2, endPoint2;
            using (Transaction trans = db.TransactionManager.StartTransaction())
            {
                Line line1 = trans.GetObject(lineId1, OpenMode.ForRead) as Line;
                startPoint1 = line1.StartPoint;
                endPoint1 = line1.EndPoint;

                Line line2 = trans.GetObject(lineId2, OpenMode.ForRead) as Line;
                startPoint2 = line2.StartPoint;
                endPoint2 = line2.EndPoint;

                trans.Commit();
            }

            // 计算等分点坐标
            Point3d[] dividePoints1 = new Point3d[divideNum + 1];
            Point3d[] dividePoints2 = new Point3d[divideNum + 1];
            for (int i = 0; i <= divideNum; i++)
            {
                dividePoints1[i] = startPoint1 + (endPoint1 - startPoint1) * i / divideNum;
                dividePoints2[i] = startPoint2 + (endPoint2 - startPoint2) * i / divideNum;
            }

            // 生成等分线段
            using (Transaction trans = db.TransactionManager.StartTransaction())
            {
                BlockTable bt = (BlockTable)trans.GetObject(db.BlockTableId, OpenMode.ForRead);
                BlockTableRecord btr = (BlockTableRecord)trans.GetObject(bt[BlockTableRecord.ModelSpace], OpenMode.ForWrite);

                for (int i = 0; i <= divideNum; i++)
                {
                    Line newLine = new Line(dividePoints1[i], dividePoints2[i]);
                    btr.AppendEntity(newLine);
                    trans.AddNewlyCreatedDBObject(newLine, true);
                }

                trans.Commit();
            }

            // 刷新CAD界面
            doc.Editor.Regen();
        }
    }
}

这段代码实现了一个名为"MyCommands"的类，其中包含一个名为"MyLineDivide"的方法，用于实现选定2根直线，输入等分数量N，计算直线N等分后N+1个等分点坐标，并由2条直线等分点成对生成N+1条直线，直线在CAD界面上显示的功能。该方法通过AutoCAD COM组件获取当前文档和数据库，然后通过用户交互方式获取两条直线和等分数量，计算等分点坐标，生成等分线段，最后刷新CAD界面，使直线显示出来。注意，该代码需要在Visual Studio中编译成类库dll文件，并在AutoCAD中加载使用。