Subscribe to the DialogBoxShowing event to be notified when Revit is just about to show a dialog box or a message box.

Namespace: Autodesk.Revit.UI
Assembly: RevitAPIUI (in RevitAPIUI.dll) Version: 21.0.0.0 (21.1.1.109)
Since:  2010

Syntax

C#
public event EventHandler<DialogBoxShowingEventArgs> DialogBoxShowing
Visual Basic
Public Event DialogBoxShowing As EventHandler(Of DialogBoxShowingEventArgs)
Visual C++
public:
 event EventHandler<DialogBoxShowingEventArgs^>^ DialogBoxShowing {
	void add (EventHandler<DialogBoxShowingEventArgs^>^ value);
	void remove (EventHandler<DialogBoxShowingEventArgs^>^ value);
}

Remarks

This event is raised when Revit is just about to show a dialog box or a message box.

Event is not cancellable. The 'Cancellable' property of event's argument is always False.

Depending on the type of the dialog that is being shown, the event's argument's type varies as follows: When it is a dialog box, the event's argument is an object of DialogBoxShowingEventArgs. When it is a message box, the event's argument is an object of MessageBoxShowingEventArgs,which is subclass of DialogBoxShowingEventArgs. When it is a task dialog, the event's argument is an object of TaskDialogShowingEventArgs,which is subclass of DialogBoxShowingEventArgs.

No document may be modified during this event.

The following API functions are not available for the current document during this event:

Exception InvalidOperationException will be thrown if any of the above methods is called during this event.

Examples

CopyC#
public class Application_DialogBoxShowing : IExternalApplication
{
    // Implement the OnStartup method to register events when Revit starts.
    public Result OnStartup(UIControlledApplication application)
    {
        // Register related events
        application.DialogBoxShowing += 
            new EventHandler<Autodesk.Revit.UI.Events.DialogBoxShowingEventArgs>(AppDialogShowing);
        return Result.Succeeded;
    }

    // Implement this method to unregister the subscribed events when Revit exits.
    public Result OnShutdown(UIControlledApplication application)
    {
        // unregister events
        application.DialogBoxShowing -= 
            new EventHandler<Autodesk.Revit.UI.Events.DialogBoxShowingEventArgs>(AppDialogShowing);
        return Result.Succeeded;
    }

    // The DialogBoxShowing event handler, which allow you to 
    // do some work before the dialog shows
    void AppDialogShowing(object sender, DialogBoxShowingEventArgs args)
    {
        // Get the string id of the showing dialog
        String dialogId = args.DialogId;

        // Format the prompt information string
        String promptInfo = "A Revit dialog will be opened.\n";
        promptInfo += "The DialogId of this dialog is " + dialogId + "\n";
        promptInfo += "If you don't want the dialog to open, please press cancel button";

        // Show the prompt message, and allow the user to close the dialog directly.
        TaskDialog taskDialog = new TaskDialog("Revit");
        taskDialog.Id = "Customer DialogId";
        taskDialog.MainContent = promptInfo;
        TaskDialogCommonButtons buttons = TaskDialogCommonButtons.Ok | 
                                            TaskDialogCommonButtons.Cancel;
        taskDialog.CommonButtons = buttons;
        TaskDialogResult result = taskDialog.Show();
        if (TaskDialogResult.Cancel == result)
        {
            // Do not show the Revit dialog
            args.OverrideResult(1);
        }
        else
        {
            // Continue to show the Revit dialog
            args.OverrideResult(0);
        }
    }
}
CopyVB.NET
Public Class Application_DialogBoxShowing
    Implements IExternalApplication
    ' Implement the OnStartup method to register events when Revit starts.
    Public Function OnStartup(application As UIControlledApplication) As Autodesk.Revit.UI.Result Implements IExternalApplication.OnStartup
        ' Register related events
        AddHandler application.DialogBoxShowing, AddressOf AppDialogShowing
        Return Result.Succeeded
    End Function

    ' Implement this method to unregister the subscribed events when Revit exits.
    Public Function OnShutdown(application As UIControlledApplication) As Autodesk.Revit.UI.Result Implements IExternalApplication.OnShutdown
        ' unregister events
        RemoveHandler application.DialogBoxShowing, AddressOf AppDialogShowing
        Return Result.Succeeded
    End Function

    ' The DialogBoxShowing event handler, which allow you to 
    ' do some work before the dialog shows
    Private Sub AppDialogShowing(sender As Object, args As DialogBoxShowingEventArgs)
        ' Get the string id of the showing dialog
        Dim dialogId As String = args.DialogId

        ' Format the prompt information string
        Dim promptInfo As [String] = "A Revit dialog will be opened." & vbLf
        promptInfo += "The DialogId of this dialog is " & dialogId & vbLf
        promptInfo += "If you don't want the dialog to open, please press cancel button"

        ' Show the prompt message, and allow the user to close the dialog directly.
        Dim taskDialog As New TaskDialog("Revit")
        taskDialog.Id = "Customer DialogId"
        taskDialog.MainContent = promptInfo
        Dim buttons As TaskDialogCommonButtons = TaskDialogCommonButtons.Ok Or TaskDialogCommonButtons.Cancel
        taskDialog.CommonButtons = buttons
        Dim result As TaskDialogResult = taskDialog.Show()
        If TaskDialogResult.Cancel = result Then
            ' Do not show the Revit dialog
            args.OverrideResult(1)
        Else
            ' Continue to show the Revit dialog
            args.OverrideResult(0)
        End If
    End Sub
End Class

See Also