Exercise: Create a New Command (.NET)

Now that you have created a project and added the necessary library references, it is time to create a command. The command will create a new multiline text (MText) object in Model space. These and other concepts are discussed in-depth in later chapters.

To define a new command that creates a new MText object

1. In the Solution Explorer, double-click Class1.cs based on the type of project you created.

   A code window is opened for the Class1 module and it should look like the following:

   using System;
   using System.Collections.Generic;
   using System.Linq;
   using System.Text;
    
   namespace MyFirstProject1
   {
     public class Class1
     {
     }
   }

2. Change the code in the code window to match the following:

   using System;
   using System.Collections.Generic;
   using System.Linq;
   using System.Text;
    
   using Autodesk.AutoCAD.Runtime;
   using Autodesk.AutoCAD.ApplicationServices;
   using Autodesk.AutoCAD.DatabaseServices;
    
   [assembly: CommandClass(typeof(MyFirstProject1.Class1))]
    
   namespace MyFirstProject1
   {
     public class Class1
     {
         [CommandMethod("AdskGreeting")]
         public void AdskGreeting()
         {
             // Get the current document and database, and start a transaction
             Document acDoc = Application.DocumentManager.MdiActiveDocument;
             Database acCurDb = acDoc.Database;
    
             // Starts a new transaction with the Transaction Manager
             using (Transaction acTrans = acCurDb.TransactionManager.StartTransaction())
             {
                 // Open the Block table record for read
                 BlockTable acBlkTbl;
                 acBlkTbl = acTrans.GetObject(acCurDb.BlockTableId,
                                              OpenMode.ForRead) as BlockTable;
    
                 // Open the Block table record Model space for write
                 BlockTableRecord acBlkTblRec;
                 acBlkTblRec = acTrans.GetObject(acBlkTbl[BlockTableRecord.ModelSpace],
                                                 OpenMode.ForWrite) as BlockTableRecord;
    
                 /* Creates a new MText object and assigns it a location,
                 text value and text style */
                 using (MText objText = new MText())
                 {
                     // Specify the insertion point of the MText object
                     objText.Location = new Autodesk.AutoCAD.Geometry.Point3d(2, 2, 0);
    
                     // Set the text string for the MText object
                     objText.Contents = "Greetings, Welcome to AutoCAD .NET";
    
                     // Set the text style for the MText object
                     objText.TextStyleId = acCurDb.Textstyle;
    
                     // Appends the new MText object to model space
                     acBlkTblRec.AppendEntity(objText);
    
                     // Appends to new MText object to the active transaction
                     acTrans.AddNewlyCreatedDBObject(objText, true);
                 }
   
                 // Saves the changes to the database and closes the transaction
                 acTrans.Commit();
             }
         }
     }
   }