Use Selection Filters to Define Selection Set Rules (.NET)

Selection filters are composed of pairs of arguments in the form of TypedValues. The first argument of a TypedValue identifies the type of filter (for example, an object), and the second argument specifies the value you are filtering on (for example, circles). The filter type is a DXF group code that specifies which filter to use. A few of the most common filter types are listed here.

DXF codes for common filters

DXF code

Filter type

0 (or DxfCode.Start)

Object Type (String)

Such as “Line,” “Circle,” “Arc,” and so forth.

2 (or DxfCode.BlockName)

Block Name (String)

The block name of an insert reference.

8 or (DxfCode.LayerName)

Layer Name (String)

Such as “Layer 0.”

60 (DxfCode.Visibility)

Object Visibility (Integer)

Use 0 = visible, 1 = invisible.

62 (or DxfCode.Color)

Color Number (Integer)

Numeric index values ranging from 0 to 256.

Zero indicates BYBLOCK. 256 indicates BYLAYER. A negative value indicates that the layer is turned off.

67

Model/paper space indicator (Integer)

Use 0 or omitted = model space, 1 = paper space.

Specify a single selection criterion for a selection set

The following code prompts users to select objects to be included in a selection set, and filters out all objects except for circles.

VB.NET

Imports Autodesk.AutoCAD.Runtime
Imports Autodesk.AutoCAD.ApplicationServices
Imports Autodesk.AutoCAD.DatabaseServices
Imports Autodesk.AutoCAD.EditorInput
 
<CommandMethod("FilterSelectionSet")> _
Public Sub FilterSelectionSet()
    '' Get the current document editor
    Dim acDocEd As Editor = Application.DocumentManager.MdiActiveDocument.Editor

    '' Create a TypedValue array to define the filter criteria
    Dim acTypValAr(0) As TypedValue
    acTypValAr.SetValue(New TypedValue(DxfCode.Start, "CIRCLE"), 0)

    '' Assign the filter criteria to a SelectionFilter object
    Dim acSelFtr As SelectionFilter = New SelectionFilter(acTypValAr)

    '' Request for objects to be selected in the drawing area
    Dim acSSPrompt As PromptSelectionResult
    acSSPrompt = acDocEd.GetSelection(acSelFtr)

    '' 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

C#

using Autodesk.AutoCAD.Runtime;
using Autodesk.AutoCAD.ApplicationServices;
using Autodesk.AutoCAD.DatabaseServices;
using Autodesk.AutoCAD.EditorInput;
 
[CommandMethod("FilterSelectionSet")]
public static void FilterSelectionSet()
{
    // Get the current document editor
    Editor acDocEd = Application.DocumentManager.MdiActiveDocument.Editor;

    // Create a TypedValue array to define the filter criteria
    TypedValue[] acTypValAr = new TypedValue[1];
    acTypValAr.SetValue(new TypedValue((int)DxfCode.Start, "CIRCLE"), 0);

    // Assign the filter criteria to a SelectionFilter object
    SelectionFilter acSelFtr = new SelectionFilter(acTypValAr);

    // Request for objects to be selected in the drawing area
    PromptSelectionResult acSSPrompt;
    acSSPrompt = acDocEd.GetSelection(acSelFtr);

    // 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");
    }
}

VBA/ActiveX Code Reference

Sub FilterSelectionSet()
    ' Create a new selection set
    Dim sset As AcadSelectionSet
    Set sset = ThisDrawing.SelectionSets.Add("SS1")
 
    ' Define the filter list, only Circle objects
    ' will be selectable
    Dim FilterType(0) As Integer
    Dim FilterData(0) As Variant
    FilterType(0) = 0
    FilterData(0) = "Circle"
 
    ' Prompt the user to select objects
    ' and add them to the selection set
    sset.SelectOnScreen FilterType, FilterData
 
    MsgBox "Number of objects selected: " & sset.Count
 
    ' Remove the selection set at the end
    sset.Delete
End Sub

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