Community
Basically, you can handle Database.ObjectModified event and in the event handler, you test if the modified entity is an Line type (or other type of your interest). If it is Line, then you raise your own custom event.
However, in ObjectModified event, you only know the entity was modified, but you do not know what change was made (moving/stretching, rotating...). if you want to riase your own event only when specific action (say, moving), then you need to handle other events that happen before ObjectModified, such as CommandWillStart and try to find the targeting entity (Line, in your case) and save its "before-change" state (start point/endpoint). so that in ObjectModified event handler, you can compare how the entity is changed. Man, it is quite complicated and could add huge overhead to AutoCAD, if the drawing has tons of Line entities.
Another possible approach might be to use TransformOverrule and override its TransformedBy virtue method (e.g raise your custom event from there). I have not tried as your requirement, but thought worth look into.
Hi Norman!
I think it is possible to compare state of entity in two events:
1) Database.ObjectOpenedForModify - before modification
2) Database.ObjectModified - after modification
Відповідь корисна? Клікніть на "ВПОДОБАЙКУ" цім повідомленням! | Do you find the posts helpful? "LIKE" these posts!
Находите сообщения полезными? Поставьте "НРАВИТСЯ" этим сообщениям!
На ваше запитання відповіли? Натисніть кнопку "ПРИЙНЯТИ РІШЕННЯ" | Have your question been answered successfully? Click "ACCEPT SOLUTION" button.
На ваш вопрос успешно ответили? Нажмите кнопку "УТВЕРДИТЬ РЕШЕНИЕ"
Alexander Rivilis / Александр Ривилис / Олександр Рівіліс
Programmer & Teacher & Helper / Программист - Учитель - Помощник / Програміст - вчитель - помічник
Facebook | Twitter | LinkedIn
 |  |
Thank you Alex for prompting me the ObjectOpenedForModify event. Yes, it can be used in conjunction with ObjectModified to watch specific entities being changed.
To 01688686718:
I put together some code quickly that watches Line entitiy or entities being changed:
using System.Collections.Generic;
using System.Linq;
using Autodesk.AutoCAD.ApplicationServices;
using Autodesk.AutoCAD.DatabaseServices;
using Autodesk.AutoCAD.EditorInput;
using Autodesk.AutoCAD.Geometry;
using Autodesk.AutoCAD.Runtime;
[assembly: CommandClass(typeof(ObjectModifiedTest.MyCommands))]
namespace ObjectModifiedTest
{
public class LineInfo
{
public ObjectId LineId { private set; get; }
public Point3d StartPoint { private set; get; }
public Point3d EndPoint { private set; get; }
public bool Changed { private set; get; }
public LineInfo(Line line)
{
LineId = line.ObjectId;
StartPoint = line.StartPoint;
EndPoint = line.EndPoint;
Changed = false;
}
public void TestChange(Line line)
{
if (line.ObjectId == this.LineId &&
(line.StartPoint != this.StartPoint &&
line.EndPoint != this.EndPoint))
Changed = true;
else
Changed = false;
}
}
public class MyCommands
{
private Dictionary<ObjectId, LineInfo> _modifiedLines = null;
private bool _watch = false;
[CommandMethod("WatchLine")]
public void RunMyCommand()
{
Document dwg = Application.DocumentManager.MdiActiveDocument;
Editor ed = dwg.Editor;
if (!_watch)
{
StartWatchLineChange(dwg);
_watch = true;
}
else
{
_watch = false;
StopWatchLineChange(dwg);
}
Autodesk.AutoCAD.Internal.Utils.PostCommandPrompt();
}
private void StartWatchLineChange(Document dwg)
{
dwg.CommandWillStart += dwg_CommandWillStart;
dwg.CommandEnded += dwg_CommandEnded;
dwg.Editor.WriteMessage("\nLine change watching is on.");
}
private void dwg_CommandWillStart(object sender, CommandEventArgs e)
{
Database db = HostApplicationServices.WorkingDatabase;
_modifiedLines = new Dictionary<ObjectId, LineInfo>();
db.ObjectOpenedForModify += Database_ObjectOpenedForModify;
db.ObjectModified += Database_ObjectModified;
}
private void dwg_CommandEnded(object sender, CommandEventArgs e)
{
if (e.GlobalCommandName.ToUpper().Contains("WATCHLINE")) return;
Database db = HostApplicationServices.WorkingDatabase;
db.ObjectOpenedForModify -= Database_ObjectOpenedForModify;
db.ObjectModified -= Database_ObjectModified;
ShowChangedLines();
}
private void Database_ObjectModified(object sender, ObjectEventArgs e)
{
if (e.DBObject is Line)
{
if (_modifiedLines.ContainsKey(e.DBObject.ObjectId))
{
_modifiedLines[e.DBObject.ObjectId].TestChange(e.DBObject as Line);
}
}
}
private void Database_ObjectOpenedForModify(object sender, ObjectEventArgs e)
{
if (e.DBObject is Line)
{
if (!_modifiedLines.ContainsKey(e.DBObject.ObjectId))
{
_modifiedLines.Add(
e.DBObject.ObjectId, new LineInfo(e.DBObject as Line));
}
}
}
private void ShowChangedLines()
{
Document dwg = Application.DocumentManager.MdiActiveDocument;
Editor ed = dwg.Editor;
foreach (var info in (from item in _modifiedLines select item.Value))
{
ed.WriteMessage(
"\nLine {0} changed: {1}",
info.LineId.ToString(), info.Changed.ToString());
}
}
private void StopWatchLineChange(Document dwg)
{
dwg.CommandWillStart -= dwg_CommandWillStart;
dwg.CommandEnded -= dwg_CommandEnded;
dwg.Editor.WriteMessage("\nLine change watching is off.");
}
}
}
Please note the command method is NOT a static method, so that the _modifiedLines Dictionary is instantiated by "per document". That is, the event halders are added/removed "per document" when "WATCHLINE" command is executed.
