Selection Class

[Autodesk.Revit.Attributes.Transaction(Autodesk.Revit.Attributes.TransactionMode.ReadOnly)]
public class Document_Selection : IExternalCommand
{
    public Autodesk.Revit.UI.Result Execute(ExternalCommandData commandData,
        ref string message, ElementSet elements)
    {
        try
        {
            // Select some elements in Revit before invoking this command

            // Get the handle of current document.
            UIDocument uidoc = commandData.Application.ActiveUIDocument;

            // Get the element selection of current document.
            Selection selection = uidoc.Selection;
            ICollection<ElementId> selectedIds = uidoc.Selection.GetElementIds();

            if (0 == selectedIds.Count)
            {
                // If no elements selected.
                TaskDialog.Show("Revit","You haven't selected any elements.");
            }
            else
            {
                String info = "Ids of selected elements in the document are: ";
                foreach (ElementId id in selectedIds)
                {
                   info += "\n\t" + id.ToString();
                }

                TaskDialog.Show("Revit",info);
            }
        }
        catch (Exception e)
        {
            message = e.Message;
            return Autodesk.Revit.UI.Result.Failed;
        }

        return Autodesk.Revit.UI.Result.Succeeded;
    }
    /// </ExampleMethod>
}

<Autodesk.Revit.Attributes.Transaction(Autodesk.Revit.Attributes.TransactionMode.[ReadOnly])> _
Public Class Document_Selection
    Implements IExternalCommand
    Public Function Execute(commandData As ExternalCommandData, ByRef message As String, elements As ElementSet) As Autodesk.Revit.UI.Result Implements IExternalCommand.Execute
        Try
            ' Select some elements in Revit before invoking this command

            ' Get the handle of current document.
            Dim uidoc As UIDocument = commandData.Application.ActiveUIDocument

            ' Get the element selection of current document.
            Dim selection As Selection = uidoc.Selection
            Dim selectedIds As ICollection(Of ElementId) = uidoc.Selection.GetElementIds()

            If 0 = selectedIds.Count Then
                ' If no elements selected.
                TaskDialog.Show("Revit", "You haven't selected any elements.")
            Else
                Dim info As [String] = "Ids of selected elements in the document are: "
                For Each id As ElementId In selectedIds
                    info += vbLf & vbTab + id.ToString()
                Next

                TaskDialog.Show("Revit", info)
            End If
        Catch e As Exception
            message = e.Message
            Return Autodesk.Revit.UI.Result.Failed
        End Try

        Return Autodesk.Revit.UI.Result.Succeeded
    End Function
    ' </ExampleMethod>
End Class

No code example is currently available or this language may not be supported.

No code example is currently available or this language may not be supported.

private void ChangeSelection(UIDocument uidoc)
{
    // Get selected elements from current document.
    ICollection<ElementId> selectedIds = uidoc.Selection.GetElementIds();

    // Display current number of selected elements
    TaskDialog.Show("Revit", "Number of selected elements: " + selectedIds.Count.ToString());

    // Go through the selected items and filter out walls only.
    ICollection<ElementId> selectedWallIds = new List<ElementId>();

    foreach (ElementId id in selectedIds)
    {
        Element elements = uidoc.Document.GetElement(id);
        if (elements is Wall)
        {
            selectedWallIds.Add(id);
        }
    }

    // Set the created element set as current select element set.
    uidoc.Selection.SetElementIds(selectedWallIds);

    // Give the user some information.
    if (0 != selectedWallIds.Count)
    {
        TaskDialog.Show("Revit", selectedWallIds.Count.ToString() + " Walls are selected!");
    }
    else
    {
        TaskDialog.Show("Revit","No Walls have been selected!");
    }
}

Private Sub ChangeSelection(uidoc As UIDocument)
    ' Get selected elements from current document.
    Dim selectedIds As ICollection(Of ElementId) = uidoc.Selection.GetElementIds()

    ' Display current number of selected elements
    TaskDialog.Show("Revit", "Number of selected elements: " + selectedIds.Count.ToString())

    ' Go through the selected items and filter out walls only.
    Dim selectedWallIds As ICollection(Of ElementId) = New List(Of ElementId)()

    For Each id As ElementId In selectedIds
        Dim elements As Element = uidoc.Document.GetElement(id)
        If TypeOf elements Is Wall Then
            selectedWallIds.Add(id)
        End If
    Next

    ' Set the created element set as current select element set.
    uidoc.Selection.SetElementIds(selectedWallIds)

    ' Give the user some information.
    If 0 <> selectedWallIds.Count Then
        TaskDialog.Show("Revit", selectedWallIds.Count.ToString() + " Walls are selected!")
    Else
        TaskDialog.Show("Revit", "No Walls have been selected!")
    End If
End Sub

No code example is currently available or this language may not be supported.

No code example is currently available or this language may not be supported.