Saving Picker Value null exception cannot convert string to model - xamarin

Question

I am having an issue with saving of my picker value. I am rewriting old code and i am struggling with saving a picker value. Once I select the picker i have the value but it doesn't go through the getter. I have similar method on other picker it works there perfectly co I dont really understand what is wrong. The only thing is that if you notice the older piece there is the Model property.Position when filling the value. Please see my notes in the code. I have Inotify in the model as advised and in the vm
public class SettingsViewModel : ObservableObject
{
private List<CustomTextSize> _textSize = new List<CustomTextSize>();
private CustomTextSize _selectedTextSize;
public CustomTextSize SelectedTextSize
{
get => _selectedTextSize; // doesnt go through here
set
{
if (_selectedTextSize != value && _selectedTextSize != null)
{
this.IsBusy = true;
SetProperty(ref _selectedTextSize, value);
NotificationService.ShowToast("Probíhá ukládání, prosím čekejte");
UserSettings newSetting = new UserSettings()
{
DateSaved = DateTime.Now,
OptionId = (int)SettingOption.TextFontSize,
Value = value.Position.ToString()
};
new Thread(new ThreadStart(async () =>
{
await LangUpDataSaverLoader.SaveUserSettings(newSetting);
LangUpDataSaverLoader.LoadUserSettingsAndFillAppValues();
})).Start();
this.IsBusy = false;
}
}
}
public List<CustomTextSize> TextSize
{
get => _textSize;
set => SetProperty(ref _textSize, value);
}
_textSize = FillTextSizeOptions();
var customSize = _textSize.FirstOrDefault(m => m.Value == LangUpUserCustomSettings.CustomFontSize); // here should be position? But then I am getting that I cannot conevrt int to Model.
if (customSize != null)
{
_selectedTextSize = customSize;
}
}
Model
public class CustomTextSize : ObservableObject {
public int Position { get; set; }
public int Value { get; set; }
public string Text { get; set; }
}
Xaml
<Picker x:Name="textSize" WidthRequest="300"
VerticalOptions="CenterAndExpand" FontSize="20"
Title="{ grial:Translate A_PickerSizeOfText }"
ItemsSource ="{Binding TextSize}" ItemDisplayBinding="{Binding Text}"
SelectedItem ="{Binding SelectedTextSize, Mode=TwoWay}"
grial:PickerProperties.BorderStyle="Default"
BackgroundColor="Transparent"
TextColor= "{ DynamicResource ListViewItemTextColor }" >
</Picker>
Old piece of code that I am rewrting
Spinner textSizeSpinner = new Spinner(MainActivity.Instance);
ArrayAdapter textSizeAdapter = new ArrayAdapter(MainActivity.Instance, Android.Resource.Layout.SimpleSpinnerDropDownItem);
textSizeAdapter.AddAll(FillTextSizeOptions().Select(m => m.Text).ToList());
textSizeSpinner.Adapter = textSizeAdapter;
textSizeSpinner.SetBackgroundColor(Color.FromHex("#3680b2").ToAndroid());
fontSizeStepper.Children.Add(textSizeSpinner);
initialTextSizeSpinnerPosition = FillTextSizeOptions().FirstOrDefault(m => m.Value == LangUpUserCustomSettings.CustomFontSize).Position; //here is the .Position
textSizeSpinner.SetSelection(initialTextSizeSpinnerPosition);
protected async void TextSizeSelected(object sender, AdapterView.ItemSelectedEventArgs e)
{
if (e.Position != initialTextSizeSpinnerPosition)
{
dialog.SetProgressStyle(ProgressDialogStyle.Spinner);
dialog.SetCancelable(false);
dialog.SetMessage("Probíhá ukládání, prosím čekejte");
dialog.Show();
Spinner spinner = (Spinner)sender;
Model.UserSettings newSetting = new Model.UserSettings()
{
DateSaved = DateTime.Now,
OptionId = (int)SettingOption.TextFontSize,
Value = FillTextSizeOptions().First(m => m.Position == e.Position).Value.ToString(),
};
await LangUpDataSaverLoader.SaveUserSettings(newSetting);
initialTextSizeSpinnerPosition = e.Position;
LangUpDataSaverLoader.LoadUserSettingsAndFillAppValues();
dialog.Dismiss();
}
}