MessageBox in a UserControl

[chasihle]

Hi,
I'm attempting to implement a message box in a UserControl. I can get MessageBox working in a window form with no issues but I receive "System.NullReferenceException: 'Object reference not set to an instance of an object.'"

Am I doing something wrong or can MessageBox not be implemented in a UserControl.
A code snippet is below.

Thanks

using Stylet;
using System.Collections.ObjectModel;
using System;
using System.Windows.Input;
using SmallBusCustMgtLibreary.Models;
using System.Collections.Generic;
using System.Windows;

namespace SmallBusCustMgtWPF.Pages
{
public class CustomerNotesViewModel : Conductor.StackNavigation, ICommand
{

    public event EventHandler CanExecuteChanged;

    public readonly IWindowManager windowManager;
    public MessageBoxResult result = new MessageBoxResult();


    public CustomerNotesViewModel(SystemTableModel sysmod, int custid)
    {
        this.windowManager = windowManager;
    }

    public void DeleteCustNote()
    {
        if(SelectedCustomerNote != null)
        { 
            DataAccess DA = new DataAccess();
            DA.DeleteCustNote(SelectedCustomerNote.CustNteId);

CustomerNote = new
ObservableCollection(DA.GetCustNoteGridRec(custId));
}
else
{
MessageBoxResult result = new MessageBoxResult();
MessageBoxViewModel.ButtonLabels[MessageBoxResult.OK] = "OK";

            result = this.windowManager.ShowMessageBox
                    ("A Customer Note Must First Be Selected", "Customer Note Delete Failed",
                                                   buttons: MessageBoxButton.OK,
                                                   buttonLabels: new Dictionary<MessageBoxResult, string>());
        //{
        //                { MessageBoxResult.Cancel, "Cancel" },
        //                });
        }
    }

    public bool CanExecute(object parameter)
    {
        throw new NotImplementedException();
    }

    
}

}

[canton7]

this.windowManager = windowManager

There's no constructor parameter called windowManager, so this assigns the field to itself. You need to pass a window manager into the constructor

[chasihle]

Thanks, that works Sent from C. Ihle's iPhone 704-439-6270

…

On Jan 2, 2021, at 1:04 PM, Antony Male ***@***.***> wrote:  this.windowManager = windowManager There's no constructor parameter called windowManager, so this assigns the field to itself. You need to pass a window manager into the constructor — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub, or unsubscribe.