You can select objects through by having the user interactively select objects, or you can simulate many of the various object selection options through the AutoCAD .NET API. If your routine performs multiple selection sets, you will need to either track each selection set returned or create an ObjectIdCollection object to keep track of all the selected objects. The following functions allow you to select objects from the drawing:
Prompts the user to pick objects from the screen.
Selects all the objects in the drawing.
Selects objects within and crossing a polygon defined by specifying points. The polygon can be any shape but cannot cross or touch itself.
Selects objects within and crossing an area defined by two points.
Selects all objects crossing a selection fence. Fence selection is similar to crossing polygon selection except that the fence is not closed, and a fence can cross itself.
Selects the last object created in the current space.
Selects all objects selected during the previous Select objects: prompt.
Selects all objects completely inside a rectangle defined by two points.
Selects objects completely inside a polygon defined by points. The polygon can be any shape but cannot cross or touch itself.
Selects objects passing through a given point and places them into the active selection set.
Selects objects within a fence and adds them to the active selection set.
This example prompts the user to select objects, then changes the color of each object selected to Green or the AutoCAD Color Index of 3.
Imports Autodesk.AutoCAD.Runtime
Imports Autodesk.AutoCAD.ApplicationServices
Imports Autodesk.AutoCAD.DatabaseServices
Imports Autodesk.AutoCAD.EditorInput
<CommandMethod("SelectObjectsOnscreen")> _
Public Sub SelectObjectsOnscreen()
'' Get the current document and database
Dim acDoc As Document = Application.DocumentManager.MdiActiveDocument
Dim acCurDb As Database = acDoc.Database
'' Start a transaction
Using acTrans As Transaction = acCurDb.TransactionManager.StartTransaction()
'' Request for objects to be selected in the drawing area
Dim acSSPrompt As PromptSelectionResult = acDoc.Editor.GetSelection()
'' If the prompt status is OK, objects were selected
If acSSPrompt.Status = PromptStatus.OK Then
Dim acSSet As SelectionSet = acSSPrompt.Value
'' Step through the objects in the selection set
For Each acSSObj As SelectedObject In acSSet
'' Check to make sure a valid SelectedObject object was returned
If Not IsDBNull(acSSObj) Then
'' Open the selected object for write
Dim acEnt As Entity = acTrans.GetObject(acSSObj.ObjectId, _
OpenMode.ForWrite)
If Not IsDBNull(acEnt) Then
'' Change the object's color to Green
acEnt.ColorIndex = 3
End If
End If
Next
'' Save the new object to the database
acTrans.Commit()
End If
'' Dispose of the transaction
End Using
End Sub
using Autodesk.AutoCAD.Runtime;
using Autodesk.AutoCAD.ApplicationServices;
using Autodesk.AutoCAD.DatabaseServices;
using Autodesk.AutoCAD.EditorInput;
[CommandMethod("SelectObjectsOnscreen")]
public static void SelectObjectsOnscreen()
{
// Get the current document and database
Document acDoc = Application.DocumentManager.MdiActiveDocument;
Database acCurDb = acDoc.Database;
// Start a transaction
using (Transaction acTrans = acCurDb.TransactionManager.StartTransaction())
{
// Request for objects to be selected in the drawing area
PromptSelectionResult acSSPrompt = acDoc.Editor.GetSelection();
// If the prompt status is OK, objects were selected
if (acSSPrompt.Status == PromptStatus.OK)
{
SelectionSet acSSet = acSSPrompt.Value;
// Step through the objects in the selection set
foreach (SelectedObject acSSObj in acSSet)
{
// Check to make sure a valid SelectedObject object was returned
if (acSSObj != null)
{
// Open the selected object for write
Entity acEnt = acTrans.GetObject(acSSObj.ObjectId,
OpenMode.ForWrite) as Entity;
if (acEnt != null)
{
// Change the object's color to Green
acEnt.ColorIndex = 3;
}
}
}
// Save the new object to the database
acTrans.Commit();
}
// Dispose of the transaction
}
}
Sub SelectObjectsOnscreen()
' Create a new selection set
Dim sset As AcadSelectionSet
Set sset = ThisDrawing.SelectionSets.Add("SS1")
' Prompt the user to select objects
' and add them to the selection set.
sset.SelectOnScreen
Dim acEnt As AcadEntity
' Step through the selected objects and change
' each object's color to Green
For Each acEnt In sset
' Use the Color property to set the object's color
acEnt.color = acGreen
Next acEnt
' Remove the selection set at the end
sset.Delete
End Sub
This example selects the objects within and that intersect a crossing window.
Imports Autodesk.AutoCAD.Runtime
Imports Autodesk.AutoCAD.ApplicationServices
Imports Autodesk.AutoCAD.DatabaseServices
Imports Autodesk.AutoCAD.Geometry
Imports Autodesk.AutoCAD.EditorInput
<CommandMethod("SelectObjectsByCrossingWindow")> _
Public Sub SelectObjectsByCrossingWindow()
'' Get the current document editor
Dim acDocEd As Editor = Application.DocumentManager.MdiActiveDocument.Editor
'' Create a crossing window from (2,2,0) to (10,8,0)
Dim acSSPrompt As PromptSelectionResult
acSSPrompt = acDocEd.SelectCrossingWindow(New Point3d(2, 2, 0), _
New Point3d(10, 8, 0))
'' If the prompt status is OK, objects were selected
If acSSPrompt.Status = PromptStatus.OK Then
Dim acSSet As SelectionSet = acSSPrompt.Value
Application.ShowAlertDialog("Number of objects selected: " & _
acSSet.Count.ToString())
Else
Application.ShowAlertDialog("Number of objects selected: 0")
End If
End Sub
using Autodesk.AutoCAD.Runtime;
using Autodesk.AutoCAD.ApplicationServices;
using Autodesk.AutoCAD.DatabaseServices;
using Autodesk.AutoCAD.Geometry;
using Autodesk.AutoCAD.EditorInput;
[CommandMethod("SelectObjectsByCrossingWindow")]
public static void SelectObjectsByCrossingWindow()
{
// Get the current document editor
Editor acDocEd = Application.DocumentManager.MdiActiveDocument.Editor;
// Create a crossing window from (2,2,0) to (10,8,0)
PromptSelectionResult acSSPrompt;
acSSPrompt = acDocEd.SelectCrossingWindow(new Point3d(2, 2, 0),
new Point3d(10, 8, 0));
// If the prompt status is OK, objects were selected
if (acSSPrompt.Status == PromptStatus.OK)
{
SelectionSet acSSet = acSSPrompt.Value;
Application.ShowAlertDialog("Number of objects selected: " +
acSSet.Count.ToString());
}
else
{
Application.ShowAlertDialog("Number of objects selected: 0");
}
}
Sub SelectObjectsByCrossingWindow()
' Create a new selection set
Dim sset As AcadSelectionSet
Set sset = ThisDrawing.SelectionSets.Add("SS1")
' Define the points for the crossing window
Dim pt1(0 To 2) As Double
Dim pt2(0 To 2) As Double
pt1(0) = 2#: pt1(1) = 2#: pt1(2) = 0#:
pt2(0) = 10#: pt2(1) = 8#: pt2(2) = 0#:
' Create a crossing window from (2,2,0) to (10,8,0)
sset.Select acSelectionSetCrossing, pt1, pt2
MsgBox "Number of objects selected: " & sset.Count
' Remove the selection set at the end
sset.Delete
End Sub