Add, change, delete

... 
 using CADImport;
 using CADImport.DWG;
 using CADImport.DXF;
 using CADImport.RasterImage;
 ...
 
 
         private void Add_change_delete_Click(object sender, EventArgs e)
         {
             //CADImage.CreateImageByExtension detects format by the extension specified in the argument. 
             //The correct class for any supported format will be used automatically. We recommend to
             //create a new drawing object with CADImage.CreateImageByExtension if import from the existed
             //file/stream is required.
             CADImage vDrawing = CADImage.CreateImageByExtension(@"..\..\..\Files\Entities.dxf");
             vDrawing.LoadFromFile(@"..\..\..\Files\Entities.dxf");
             // Changes color
 	        vDrawing.CurrentLayout.Entities[1].Color = Color.Blue;
 	        vDrawing.CurrentLayout.Entities[1].LineWeight = 2;
 	        vDrawing.Converter.Loads(vDrawing.CurrentLayout.Entities[1]);
             //Removes the circle entity from the Entities.dxf drawing
 	        vDrawing.CurrentLayout.Entities.RemoveAt(2);
             // Creating a new entity - line
         	CADLine vLine = new CADLine();
 	        vLine.Point = new DPoint(50, 0, 0);
 	        vLine.Point1 = new DPoint(50, 70, 10);
 	        vLine.LineWeight = 1;
 	        vDrawing.Converter.Loads(vLine);
 	        vDrawing.CurrentLayout.AddEntity(vLine);
             // Recalculates the extents of the drawing
 	        vDrawing.GetExtents();
             // Adjusting visualization sizes to the control area:
             RectangleF vRect;
             double vRatio = (double)(vDrawing.AbsHeight * Image1.ClientSize.Width) / (vDrawing.AbsWidth * Image1.ClientSize.Height);
             if (vRatio > 1)
                 vRect = new RectangleF(0, 0, (float)(Image1.ClientSize.Width / vRatio), (float)Image1.ClientSize.Height);
             else
                 vRect = new RectangleF(0, 0, (float)Image1.ClientSize.Width, (float)(Image1.ClientSize.Height * vRatio));
             //-----------------------------------------------
             vDrawing.Draw(Image1.CreateGraphics(), vRect);
         }