Identify and Manipulate the Active Viewport

The active viewport is represented in the Viewports table by a record named "*Active", which is not a unique name as all tiled viewports currently displayed on the Model tab are named "*Active". Each tiled viewport that is displayed is assigned a number. The number of the active viewport can be obtained by:

Retrieving the value of the CVPORT system variable
Using the ActiveViewportId property of the Editor object to get the object id for the active viewport and then open the Viewport object to access its Number property

Once you have the active viewport, you control its display properties, enable drafting aids for the viewport such as grid and snap, as well as the size of the viewport itself. Tiled viewports are defined by two corner points: lower-left and upper-right. The LowerLeftCorner and UpperRightCorner properties represent the graphic placement of the viewport on the display.

A single tiled viewport configuration has a lower-left corner of (0,0) and an upper-right corner of (1,1). The lower-left corner of the drawing window is always represented by the point of (0,0), and the upper-right corner is presented by (1,1) no matter the number of tiled viewports on the Model tab. When more than one tiled viewport is displayed, the lower-left and upper-right corners will vary but one viewport will have a lower-left corner of (0,0) and another will have an upper-right corner of (1,1)

These properties are defined as follows (using a four-way split as an example):

In this example:

Viewport 1-LowerLeftCorner = (0, .5), UpperRightCorner = (.5, 1)
Viewport 2-LowerLeftCorner = (.5, .5), UpperRightCorner = (1, 1)
Viewport 3-LowerLeftCorner = (0, 0), UpperRightCorner = (.5, .5)
Viewport 4-LowerLeftCorner = (.5, 0), UpperRightCorner = (1, .5)

Create a new tiled viewport configuration with two horizontal windows

The following example creates a two horizontal viewports as a named viewport configuration and redefines the active display.

VB.NET

Imports Autodesk.AutoCAD.ApplicationServices

Imports Autodesk.AutoCAD.DatabaseServices

Imports Autodesk.AutoCAD.Runtime

Imports Autodesk.AutoCAD.Geometry

<CommandMethod("CreateModelViewport")> _

Public Sub CreateModelViewport()

  '' Get the current database

  Dim acDoc As Document = Application.DocumentManager.MdiActiveDocument

  Dim acCurDb As Database = acDoc.Database

  '' Start a transaction

  Using acTrans As Transaction = acCurDb.TransactionManager.StartTransaction()

      '' Open the Viewport table for read

      Dim acVportTbl As ViewportTable

      acVportTbl = acTrans.GetObject(acCurDb.ViewportTableId, OpenMode.ForRead)

      '' Check to see if the named view 'TEST_VIEWPORT' exists

      If (acVportTbl.Has("TEST_VIEWPORT") = False) Then

          '' Open the View table for write

          acVportTbl.UpgradeOpen()

          '' Add the new viewport to the Viewport table and the transaction

          Dim acVportTblRecLwr As ViewportTableRecord = New ViewportTableRecord()

          acVportTbl.Add(acVportTblRecLwr)

          acTrans.AddNewlyCreatedDBObject(acVportTblRecLwr, True)

          '' Name the new viewport 'TEST_VIEWPORT' and assign it to be

          '' the lower half of the drawing window

          acVportTblRecLwr.Name = "TEST_VIEWPORT"

          acVportTblRecLwr.LowerLeftCorner = New Point2d(0, 0)

          acVportTblRecLwr.UpperRightCorner = New Point2d(1, 0.5)

          '' Add the new viewport to the Viewport table and the transaction

          Dim acVportTblRecUpr As ViewportTableRecord = New ViewportTableRecord()

          acVportTbl.Add(acVportTblRecUpr)

          acTrans.AddNewlyCreatedDBObject(acVportTblRecUpr, True)

          '' Name the new viewport 'TEST_VIEWPORT' and assign it to be

          '' the upper half of the drawing window

          acVportTblRecUpr.Name = "TEST_VIEWPORT"

          acVportTblRecUpr.LowerLeftCorner = New Point2d(0, 0.5)

          acVportTblRecUpr.UpperRightCorner = New Point2d(1, 1)

          '' To assign the new viewports as the active viewports, the

          '' viewports named '*Active' need to be removed and recreated

          '' based on 'TEST_VIEWPORT'.

          '' Step through each object in the symbol table

          For Each acObjId As ObjectId In acVportTbl

              '' Open the object for read

              Dim acVportTblRec As ViewportTableRecord

              acVportTblRec = acTrans.GetObject(acObjId, _

                                                OpenMode.ForRead)

              '' See if it is one of the active viewports, and if so erase it

              If (acVportTblRec.Name = "*Active") Then

                  acVportTblRec.UpgradeOpen()

                  acVportTblRec.Erase()

              End If

          Next

          '' Clone the new viewports as the active viewports

          For Each acObjId As ObjectId In acVportTbl

              '' Open the object for read

              Dim acVportTblRec As ViewportTableRecord

              acVportTblRec = acTrans.GetObject(acObjId, _

                                                OpenMode.ForRead)

              '' See if it is one of the active viewports, and if so erase it

              If (acVportTblRec.Name = "TEST_VIEWPORT") Then

                  Dim acVportTblRecClone As ViewportTableRecord

                  acVportTblRecClone = acVportTblRec.Clone()

                  '' Add the new viewport to the Viewport table and the transaction

                  acVportTbl.Add(acVportTblRecClone)

                  acVportTblRecClone.Name = "*Active"

                  acTrans.AddNewlyCreatedDBObject(acVportTblRecClone, True)

              End If

          Next

          '' Update the display with the new tiled viewports arrangement

          acDoc.Editor.UpdateTiledViewportsFromDatabase()

          '' Commit the changes

          acTrans.Commit()

      End If

      '' Dispose of the transaction

  End Using

End Sub

using Autodesk.AutoCAD.ApplicationServices;

using Autodesk.AutoCAD.DatabaseServices;

using Autodesk.AutoCAD.Runtime;

using Autodesk.AutoCAD.Geometry;

[CommandMethod("CreateModelViewport")]

public static void CreateModelViewport()

  // Get the current database

  Document acDoc = Application.DocumentManager.MdiActiveDocument;

  Database acCurDb = acDoc.Database;

  // Start a transaction

  using (Transaction acTrans = acCurDb.TransactionManager.StartTransaction())

      // Open the Viewport table for read

      ViewportTable acVportTbl;

      acVportTbl = acTrans.GetObject(acCurDb.ViewportTableId,

                                     OpenMode.ForRead) as ViewportTable;

      // Check to see if the named view 'TEST_VIEWPORT' exists

      if (acVportTbl.Has("TEST_VIEWPORT") == false)

          // Open the View table for write

          acVportTbl.UpgradeOpen();

          // Add the new viewport to the Viewport table and the transaction

          ViewportTableRecord acVportTblRecLwr = new ViewportTableRecord();

          acVportTbl.Add(acVportTblRecLwr);

          acTrans.AddNewlyCreatedDBObject(acVportTblRecLwr, true);

          // Name the new viewport 'TEST_VIEWPORT' and assign it to be

          // the lower half of the drawing window

          acVportTblRecLwr.Name = "TEST_VIEWPORT";

          acVportTblRecLwr.LowerLeftCorner = new Point2d(0, 0);

          acVportTblRecLwr.UpperRightCorner = new Point2d(1, 0.5);

          // Add the new viewport to the Viewport table and the transaction

          ViewportTableRecord acVportTblRecUpr = new ViewportTableRecord();

          acVportTbl.Add(acVportTblRecUpr);

          acTrans.AddNewlyCreatedDBObject(acVportTblRecUpr, true);

          // Name the new viewport 'TEST_VIEWPORT' and assign it to be

          // the upper half of the drawing window

          acVportTblRecUpr.Name = "TEST_VIEWPORT";

          acVportTblRecUpr.LowerLeftCorner = new Point2d(0, 0.5);

          acVportTblRecUpr.UpperRightCorner = new Point2d(1, 1);

          // To assign the new viewports as the active viewports, the

          // viewports named '*Active' need to be removed and recreated

          // based on 'TEST_VIEWPORT'.

          // Step through each object in the symbol table

          foreach (ObjectId acObjId in acVportTbl)

              // Open the object for read

              ViewportTableRecord acVportTblRec;

              acVportTblRec = acTrans.GetObject(acObjId,

                                                OpenMode.ForRead) as ViewportTableRecord;

              // See if it is one of the active viewports, and if so erase it

              if (acVportTblRec.Name == "*Active")

                  acVportTblRec.UpgradeOpen();

                  acVportTblRec.Erase();

          // Clone the new viewports as the active viewports

          foreach (ObjectId acObjId in acVportTbl)

              // Open the object for read

              ViewportTableRecord acVportTblRec;

              acVportTblRec = acTrans.GetObject(acObjId,

                                                OpenMode.ForRead) as ViewportTableRecord;

              // See if it is one of the active viewports, and if so erase it

              if (acVportTblRec.Name == "TEST_VIEWPORT")

                  ViewportTableRecord acVportTblRecClone;

                  acVportTblRecClone = acVportTblRec.Clone() as ViewportTableRecord;

                  // Add the new viewport to the Viewport table and the transaction

                  acVportTbl.Add(acVportTblRecClone);

                  acVportTblRecClone.Name = "*Active";

                  acTrans.AddNewlyCreatedDBObject(acVportTblRecClone, true);

          // Update the display with the new tiled viewports arrangement

          acDoc.Editor.UpdateTiledViewportsFromDatabase();

          // Commit the changes

          acTrans.Commit();

      // Dispose of the transaction

VBA/ActiveX Code Reference