How do I disable an action in a nested listview if there is no record? - xaf

Question

I have a PopUpWindowShowAction that operates on the current record.
If there is no current record then I want the action disabled.
This is because if there is no record the PopUpWindowShowAction will fail.
Here is my simplified controller
using DevExpress.ExpressApp;
using DevExpress.ExpressApp.Actions;
using DevExpress.ExpressApp.Editors;
using System;
using System.Linq;
using System.Windows.Forms;
namespace MyNamespace
{
public partial class JobWorkflowController : ViewController
{
PopupWindowShowAction actWorkflow;
public JobWorkflowController()
{
TargetObjectType = typeof(IWorkflow);
actWorkflow = new PopupWindowShowAction(this, "Workflow", "Admin")
{ AcceptButtonCaption = string.Empty, ActionMeaning = ActionMeaning.Accept, CancelButtonCaption = null, Caption = "Workflow", ConfirmationMessage = null, ImageName = "Workflow", Shortcut = "F7", ToolTip = null };
actWorkflow.CustomizePopupWindowParams += actWorkflow_CustomizePopupWindowParams_1;
actWorkflow.Execute += actWorkflow_Execute_1;
actWorkflow.Cancel += actWorkflow_Cancel;
}
private void actWorkflow_CustomizePopupWindowParams_1(object sender, CustomizePopupWindowParamsEventArgs e)
{
if (View.CurrentObject is not IWorkflow wf)
{
// causes an error because the view is not set
return;
}
// code to create the popup view
}
private void actWorkflow_Execute_1(object sender, PopupWindowShowActionExecuteEventArgs e)
{
// code
}
private void actWorkflow_Cancel(object sender, EventArgs e)
{
// code
}
protected override void OnActivated()
{
base.OnActivated();
View.CurrentObjectChanged += View_CurrentObjectChanged;
View_CurrentObjectChanged(View, new EventArgs());
}
private void View_CurrentObjectChanged(object sender, EventArgs e)
{
actWorkflow.Enabled["HasCurrent"]= View.CurrentObject != null;
}
protected override void OnDeactivated()
{
View.CurrentObjectChanged -= View_CurrentObjectChanged;
base.OnDeactivated();
}
}
}
The View_CurrentObjectChanged event fires but the action does not disable.
[Update]
I tried Michael's suggestion but the action des not disable.

Answer 1

Put this in your constructor
actWorkflow.SelectionDependencyType = SelectionDependencyType.RequireSingleObject
And it will only be active when a single object is selected. If you'd like to have one or more objects selected it's:
actWorkflow.SelectionDependencyType = SelectionDependencyType.RequireMultipleObjects;
You'll have no need to subscribe to the CurrentObjectChanged event.