IExternalCommand Interface

Namespace: Autodesk.Revit.UI
Assembly: RevitAPIUI (in RevitAPIUI.dll) Version: 25.3.0.0 (25.3.0.0)

Syntax

C#

public interface IExternalCommand

The IExternalCommand type exposes the following members.

Methods

Remarks

To add an external command to Autodesk Revit the developer should implement an object that supports the IExternalCommand interface.

Example

C#

public Autodesk.Revit.UI.Result Execute(ExternalCommandData commandData,
    ref string message, ElementSet elements)
{
    try
    {
        Document doc = commandData.Application.ActiveUIDocument.Document;
        UIDocument uidoc = commandData.Application.ActiveUIDocument;
        // Delete selected elements

        ICollection<Autodesk.Revit.DB.ElementId> ids =
            doc.Delete(uidoc.Selection.GetElementIds());

        TaskDialog taskDialog = new TaskDialog("Revit"); 
        taskDialog.MainContent = 
           ("Click Yes to return Succeeded. Selected members will be deleted.\n" +
           "Click No to return Failed.  Selected members will not be deleted.\n" +
           "Click Cancel to return Cancelled.  Selected members will not be deleted.");
        TaskDialogCommonButtons buttons = TaskDialogCommonButtons.Yes | 
            TaskDialogCommonButtons.No | TaskDialogCommonButtons.Cancel;
        taskDialog.CommonButtons = buttons;
        TaskDialogResult taskDialogResult = taskDialog.Show();

        if (taskDialogResult == TaskDialogResult.Yes)
        {
            return Autodesk.Revit.UI.Result.Succeeded;
        }
        else if (taskDialogResult == TaskDialogResult.No)
        {
            ICollection<ElementId> selectedElementIds = uidoc.Selection.GetElementIds();
            foreach (ElementId id in selectedElementIds)
            {
                elements.Insert( doc.GetElement(id) );
            }
            message = "Failed to delete selection.";
            return Autodesk.Revit.UI.Result.Failed;
        }
        else
        {
            return Autodesk.Revit.UI.Result.Cancelled;
        }
    }
    catch
    {
        message = "Unexpected Exception thrown.";
        return Autodesk.Revit.UI.Result.Failed;
    }

}

VB

Public Function Execute(commandData As ExternalCommandData, ByRef message As String, elements As ElementSet) As Autodesk.Revit.UI.Result Implements IExternalCommand.Execute
    Try
        Dim doc As Document = commandData.Application.ActiveUIDocument.Document
        Dim uidoc As UIDocument = commandData.Application.ActiveUIDocument
        ' Delete selected elements

        Dim ids As ICollection(Of Autodesk.Revit.DB.ElementId) = doc.Delete(uidoc.Selection.GetElementIds())

        Dim taskDialog As New TaskDialog("Revit")
        taskDialog.MainContent = ("Click Yes to return Succeeded. Selected members will be deleted." & vbLf & "Click No to return Failed.  Selected members will not be deleted." & vbLf & "Click Cancel to return Cancelled.  Selected members will not be deleted.")
        Dim buttons As TaskDialogCommonButtons = TaskDialogCommonButtons.Yes Or TaskDialogCommonButtons.No Or TaskDialogCommonButtons.Cancel
        taskDialog.CommonButtons = buttons
        Dim taskDialogResult__1 As TaskDialogResult = taskDialog.Show()

        If taskDialogResult__1 = TaskDialogResult.Yes Then
            Return Autodesk.Revit.UI.Result.Succeeded
        ElseIf taskDialogResult__1 = TaskDialogResult.No Then
            Dim selectedElementIds As ICollection(Of ElementId) = uidoc.Selection.GetElementIds()
            For Each id As ElementId In selectedElementIds
                elements.Insert(doc.GetElement(id))
            Next
            message = "Failed to delete selection."
            Return Autodesk.Revit.UI.Result.Failed
        Else
            Return Autodesk.Revit.UI.Result.Cancelled
        End If
    Catch
        message = "Unexpected Exception thrown."
        Return Autodesk.Revit.UI.Result.Failed
    End Try

End Function

See Also

Reference