Changing the colour of nested AutoCAD entities through .NET

Someone asked me earlier today how to iteratively change the color of entities inside blocks.

The following code uses a recursive helper function to iterate down through the contents of a block, changing the various entities (other than block references, for which we simply recurse) to a specified colour.

Here's the C# code:

using Autodesk.AutoCAD.ApplicationServices;

using Autodesk.AutoCAD.DatabaseServices;

using Autodesk.AutoCAD.EditorInput;

using Autodesk.AutoCAD.Runtime;

using Autodesk.AutoCAD.Colors;

namespace BlockTest

{

  public class BlockCmds

  {

    [CommandMethod("CC")]

    public void ChangeColor()

    {

      Document doc =

        Application.DocumentManager.MdiActiveDocument;

      Database db = doc.Database;

      Editor ed = doc.Editor;

      PromptIntegerResult pr =

        ed.GetInteger(

          "\nEnter color index to change all entities to: "

        );

      if (pr.Status == PromptStatus.OK)

      {

        short newColorIndex = (short)pr.Value;

        ObjectId msId;

        Transaction tr =

          doc.TransactionManager.StartTransaction();

        using (tr)

        {

          BlockTable bt =

            (BlockTable)tr.GetObject(

              db.BlockTableId,

              OpenMode.ForRead

            );

          msId =

            bt[BlockTableRecord.ModelSpace];

          // Not needed, but quicker than aborting

          tr.Commit();

        }

        int count =

          ChangeNestedEntitiesToColor(msId, newColorIndex);

        ed.Regen();

        ed.WriteMessage(

          "\nChanged {0} entit{1} to color {2}.",

          count,

          count == 1 ? "y" : "ies",

          newColorIndex

        );

      }

    }

    private int ChangeNestedEntitiesToColor(

      ObjectId btrId, short colorIndex)

    {

      int changedCount = 0;

      Document doc =

        Application.DocumentManager.MdiActiveDocument;

      Database db = doc.Database;

      Editor ed = doc.Editor;

      Transaction tr =

        doc.TransactionManager.StartTransaction();

      using (tr)

      {

        BlockTableRecord btr =

          (BlockTableRecord)tr.GetObject(

            btrId,

            OpenMode.ForRead

          );

        foreach (ObjectId entId in btr)

        {

          Entity ent =

            tr.GetObject(entId, OpenMode.ForRead)

            as Entity;

          if (ent != null)

          {

            BlockReference br = ent as BlockReference;

            if (br != null)

            {

              // Recurse for nested blocks

              changedCount +=

                ChangeNestedEntitiesToColor(

                  br.BlockTableRecord,

                  colorIndex

                );

            }

            else

            {

              if (ent.ColorIndex != colorIndex)

              {

                changedCount++;

                // Entity is only open for read

                ent.UpgradeOpen();

                ent.ColorIndex = colorIndex;

                ent.DowngradeOpen();

              }

            }

          }

        }

        tr.Commit();

      }

      return changedCount;

    }

  }

}

Comments

[Claudio]

Dear Kean

I´m working with .Net and Autocad. I´m trying to run a rutine that change the color of an object (line), I know how
to do this with one color, but i want to change the line in various colors, for example from red to green to yellow in intervals of time, the rutine must be run while i´m working
in the draw ( for example while i´m doing zoom ) but i need the line back to the original color when i do a click (event)
with the mouse. I can´t find the solution, can you help me ?!

[Kean]

Dear Claudio,

It's certainly possible to set a timer and cycle through colours on a set of objects - the issue is doing so during a realtime pan/zoom and also accessing the database in a safe way irrespective of what is happening in the editor.

Frankly I'd look at leveraging the in-built selection highlighting mechanism inside AutoCAD, which would be much safer.

Regards,

Kean

[Tony]

Kean,
thanks for your info, but I am still stuck. I am using acad2006 - I have a folder full of small A3 drgs, each with a title block. I want to update the attributes of the Revision from A to B and insert "issued for construction" and the date etc. How can I do this using Global Attribute Editing techniques for Multiple drawings?
Cheers
TonyE

[Kean]

TonyE,

I suggest checking out this post.

Regards,

Kean

[Kean]

TonyE,

I suggest checking out this post.

Regards,

Kean