[原著翻译]c#.net改变AutoCAD块中内容的颜色（用c#对autocad进行二次开发系列之一）

c#.net改变AutoCAD块中内容的颜色

下面是我最近遇到的一个问题：

在.net中我如何调出AutoCAD的颜色对话框呢？我需要让用户选择一个块，然后弹出AutoCAD的颜色选择对话框，然后用用户选择的颜色来运用到选择的块中的内容中。

总部设在圣保罗的DevTech Americas的一个新成员-Augusto Gonçalves,用如下的代码回答了我的问题（我进行了细微的修改，为了使这篇blog上的代码便于阅读）。谢谢您，Augusto！

顺便说一句，这里有一篇旧博客，或许对这个话题感兴趣的人有些用处。

下面是用c#写得代码：

Code

using Autodesk.AutoCAD.ApplicationServices;

using Autodesk.AutoCAD.DatabaseServices;

using Autodesk.AutoCAD.EditorInput;

using Autodesk.AutoCAD.Runtime;

using Autodesk.AutoCAD.Windows;

using Autodesk.AutoCAD.Colors;

namespace ColorPicking

{

 public class Commands

  {

    [CommandMethod("CB")]

    public void ColorBlock()

    {

      Document doc =

          Application.DocumentManager.MdiActiveDocument;

      Database db = doc.Database;

      Editor ed = doc.Editor;

      // Ask the user to select a block

      PromptEntityOptions peo =

        new PromptEntityOptions(""nSelect a block:");      

      peo.AllowNone = false;

      peo.SetRejectMessage(""nMust select a block.");

      peo.AddAllowedClass(typeof(BlockReference), false);

      PromptEntityResult per =

        ed.GetEntity(peo);

      if (per.Status != PromptStatus.OK)

        return;

      // Open the entity using a transaction

      Transaction tr =

        db.TransactionManager.StartTransaction();

      using (tr)

      {

        try

        {

          Entity ent =

            (Entity)tr.GetObject(

              per.ObjectId,

              OpenMode.ForRead

            );

          // Should always be a block reference,

          // but let's make sure

          BlockReference br = ent as BlockReference;

          if (br != null)

          {

            // Select the new color

            ColorDialog cd = new ColorDialog();

            cd.IncludeByBlockByLayer = true;

            cd.ShowDialog();

            // Change the color of the block itself

            br.UpgradeOpen();

            br.Color = cd.Color;

            // Change every entity to be of color ByBlock

            BlockTableRecord btr =

              (BlockTableRecord)tr.GetObject(

                br.BlockTableRecord,

                OpenMode.ForRead

              );

            // Iterate through the BlockTableRecord contents

            foreach (ObjectId id in btr)

            {

              // Open the entity

              Entity ent2 =

                (Entity)tr.GetObject(id, OpenMode.ForWrite);

              // Change each entity's color to ByBlock

              ent2.Color =

                Color.FromColorIndex(ColorMethod.ByBlock, 0);

            }

          }

          // Commit if there hasn't been a problem

          // (even if no objects changed: it's just quicker)

          tr.Commit();

        }

        catch (Autodesk.AutoCAD.Runtime.Exception e)

        {

          // Something went wrong

          ed.WriteMessage(e.ToString());

        }

      }

    }

  }

}