Get "parent" Window of a Page when the window is loaded (WPF)

Question

In my program, I have to open a Window with two Pages, and I need to pass some string info to these Pages. I use an attribute on the "parent" Window to do so, which I initialize on the Window constructor.

My problem comes when I try to get the parent Window of one of those Pages on its constructor. I believe I have to do this because I need the string info right at the start, to fill a Combobox.

I try getting the Window this way:

parentWindow = (AsistenteWindow)Window.GetWindow(this);

But when the Page initializes, it gives me a NullReferenceException. I thought the problem was that the Window isn't fully loaded when the Page initialization takes place, but I'm not sure about this.

My Window code is:

public partial class AsistenteWindow : Window
    {

        #region Atributos
        public string Resultado { get; set; } = "";
        public string ModeloDispSeleccionado { get; set; } = "";
        public string NumeroCluster { get; set; }
        public string TextoCluster { get; set; }
        #endregion

        public AsistenteWindow(string modelo)
        {
            InitializeComponent();

            ModeloDispSeleccionado = modelo;
        }
    }

The string attributes are the ones I have to access from the Pages.

And my first Page code is:

public partial class AsistenteClusterPage : Page
    {

        private Dictionary<string, string> dicClusters = new Dictionary<string, string>();
        private AsistenteWindow parentWindow;


        public AsistenteClusterPage()
        {
            InitializeComponent();

            parentWindow = (AsistenteWindow)Window.GetWindow(this);

            try
            {
                // crea un diccionario con todos los clusters y el texto para mostrar, asegurando que no se repitan
                foreach (DataRow mccRow in SQLiteHelper.TramasDataSet.Tables["ModeloClusterCanal"].Rows)
                {
                    if (mccRow["ModeloId"].ToString() == parentWindow.ModeloDispSeleccionado)
                    {
                        foreach (DataRow clRow in SQLiteHelper.TramasDataSet.Tables["Cluster"].Rows)
                        {
                            if (clRow["ClusterId"].ToString() == mccRow["ClusterId"].ToString()
                                && !dicClusters.ContainsKey(clRow["ClusterId"].ToString()))
                            {
                                dicClusters.Add(clRow["ClusterId"].ToString(), clRow["ClusterName"] + " (" + clRow["ClusterId"].ToString() + ")");
                            }
                        }
                    }
                }

                // rellena el ComboBox con los clusters
                foreach (KeyValuePair<string, string> keyValue in dicClusters)
                {
                    cbCluster.Items.Add(new ComboBoxItem(keyValue.Value, keyValue.Key));
                }
            }

            catch (Exception ex)
            {
                Console.WriteLine(ex.Message + "/n" + ex.StackTrace);

            }
        }
    }

(I won't post the code for the other Page because it's too long, but I also have to access the string info from there in a similar way, so I guess there will be a problem too)

I also need to be able to close the parent Window from within the Pages.

Is there a better approach for this? Should I not use the attributes in the parent Window, and should I then pass the string info in another way?

Answer 1

I ended up using the Application.Current.Properties dictionary to store the string info, like it's said in this post. It gives no errors.

Then, to close the Window, I use Window.GetWindow(this).Close(); as said in many questions about getting the parent Window. This doesn't give any error because I get the Window when it's already loaded (it closes when a button is pressed).

I guess this is the best approach I can get right now. Still I don't know if using the Application.Current.Properties is the best option for this?

EDIT: Instead of using the Window.GetWindow(this).Close(); I'm using the IsCancel attribute of the button now, as said @XAMIMAX.