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.vb or 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:

   VB.NET

   Public Class Class1
    
   End Class

   C#

   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:

   VB.NET

   Imports Autodesk.AutoCAD.Runtime
   Imports Autodesk.AutoCAD.ApplicationServices
   Imports Autodesk.AutoCAD.DatabaseServices
        
   Public Class Class1
     <CommandMethod("AdskGreeting")> _
     Public Sub AdskGreeting()
         '' Get the current document and database, and start a transaction
         Dim acDoc As Document = Application.DocumentManager.MdiActiveDocument
         Dim acCurDb As Database = acDoc.Database
    
         Using acTrans As Transaction = acCurDb.TransactionManager.StartTransaction()
             '' Open the Block table record for read
             Dim acBlkTbl As BlockTable
             acBlkTbl = acTrans.GetObject(acCurDb.BlockTableId, _
                                          OpenMode.ForRead)
    
             '' Open the Block table record Model space for write
             Dim acBlkTblRec As BlockTableRecord
             acBlkTblRec = acTrans.GetObject(acBlkTbl(BlockTableRecord.ModelSpace), _
                                             OpenMode.ForWrite)
    
             '' Creates a new MText object and assigns it a location,
             '' text value and text style
             Using objText As MText = 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)
             End Using
   
             '' Saves the changes to the database and closes the transaction
             acTrans.Commit()
         End Using
     End Sub
   End Class

   C#

   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();
             }
         }
     }
   }