Exercise: Create a New Command

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

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
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Public Class Class1
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```
 
```
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End Class
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C#
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using System;
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using System.Collections.Generic;
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using System.Linq;
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using System.Text;
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```
 
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namespace MyFirstProject1
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{
```
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  public class Class1
```
```
  {
```
```
  }
```
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}
```

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

          Dim 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 the AutoCAD .NET Developer's Guide"

          '' Set the text style for the MText object

          objText.TextStyle = 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()

      End Using

  End Sub

End Class

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 */

              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 the AutoCAD .NET Developer's Guide";

              // 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();