How to persist data in the SFDataGrid when device changes orientation

[Samuel Otero]

Hello

I have this grid filled with data. The code is simple:

           grid = new SfDataGrid(this);

            grid.AllowResizingColumn = true;

            grid.AllowSorting = true;

    

            layout.AddView(grid);

            string dpPath = Path.Combine("/data/data/TPProject.TPProject/files/", "PranfHurto.db3");

            var db = new SQLiteConnection(dpPath);

            grid.ItemsSource = db.Table<v_Casos>(); //This is SQLite

However if the device change it's orientation, the OnCreate method is called again, basically needing to re-query the table, and this takes times. I need to save the state of the ItemSources in the grid, so I don't need to query the table again. In this post of Xamarin, they explain how to save the activity state, however db.Table<v_Casos>(); returns a list, and I'm not sure how to save a whole list of v_Casos type inside the Outstate.

Any thoughts about how to achieve this?? Thank you!

[Samuel Otero]

Following this Xamarin suggestion I think I'm able to persist the data if I serialize the object to a Json string. However something is wrong. My "savedInstanceState.GetString("jsonData")" always comes back null because OnSaveInstanceState never gets called!!

Here is my code:

protected override void OnCreate(Bundle savedInstanceState)

        {

            base.OnCreate(savedInstanceState);

            SetContentView(Resource.Layout.CaseControl);

            RelativeLayout layout = FindViewById(Resource.Id.layoutCasos);

            grid = new SfDataGrid(this);

            grid.AllowResizingColumn = true;

            grid.AllowSorting = true;

    

            layout.AddView(grid);

            if (savedInstanceState != null)

            {

               string savedJsonData = savedInstanceState.GetString("jsonData");

               grid.ItemsSource = JsonConvert.DeserializeObject>(savedJsonData);

            }

            else

            {

                string dpPath = Path.Combine("/data/data/TPProject.TPProject/files/", "PranfHurto.db3");

                var db = new SQLiteConnection(dpPath);

                var data = db.Table();

                grid.ItemsSource = data;

                jsonData = JsonConvert.SerializeObject(data);

            }

            grid.SelectionMode = SelectionMode.Single;

            grid.GridLongPressed += RowLongPress;

            

        }

        protected override void OnSaveInstanceState(Bundle outState)

        {

            outState.PutString("jsonData", jsonData);

            base.OnSaveInstanceState(outState);

        }

So, what I'm doing wrong?? Help! Thank you!

[Samuel Otero]

I read in another post a similar problem and the weird solution was re copy and pasting the overriden method. Now it started to work. Thank you.

[Ashok N]

Hi Samuel, 

Thanks for your update. Please let us know if you require further assistance on this.  

Regards, 

Ashok