I'm working on my app that will get data from online database. I would like to show progress bar. Problem is that I can not make it work.

Current situation is:

• I am using FreshMVVM.
• Method to get data form online is in class FirebaseCloudNight. There is static method SynchronizeNights with which I get all nights (with function foreach). I would like to show progress bar based on nights done/remaining to be synchronized.
• In ViewModel I have property CurrentProgress that is correctly bidden to View. I can not update this property correctly.
• I left out a lot of code because I think is irrelevant. If you need more code please let me know.
• The only solution I found is to create new instance of MV class. But after additional reading I found out that, although I see that property changed, binding was not OK, because it changed new instance of property.

Issue is that the only way I found is to update this property based on new instance. But then MVVM does not work --> UI is not refreshed because it updates different instance of property. How can this be done?

Below is my code (if it will be of any help).

Code to retrieve DB from cloud

namespace iVanApp.Services {
public class FirebaseCloudNight : FirebaseCloudBaseHelper
{
    
    static public async Task<bool> SynchronizeNights()
    {
        // Synchronize from Cloud to DB
        foreach (var cloudItem in cloudNights)
        {
            CurrentProgress= currentNight / numberOfNights;
            try
            { 
                //Here I removed code for retriving data from online DB
                currentNight   ;
            }
            catch (Exception ex)
            {
                return false;
            }
            return true;
        }
     }
 }

ViewModel Code

 async Task GetData()
    {
            bool success = await FirebaseCloudNight.SynchronizeNights();>                 
    }

    float currentProgress;
    public float CurrentProgress
    {
        get => currentProgress;
        set
        {
            currentProgress = value;
            RaisePropertyChanged();
        }
    }

EDIT: What I tried and does not work (because of obvious reasons)

namespace iVanApp.Services {
public class FirebaseCloudNight : FirebaseCloudBaseHelper
{
    
    static public async Task<bool> SynchronizeNights()
    {
        // Synchronize from Cloud to DB
        var VM = new UserAuthenticationPageModel();
        foreach (var cloudItem in cloudNights)
        {
            VM.CurrentProgress = currentNight / numberOfNights;
            try
            { 
                //Here I removed code for retriving data from online DB
                currentNight   ;
            }
            catch (Exception ex)
            {
                return false;
            }
            return true;
        }
     }
 }

CodePudding user response：

Found an answer that is working

Added code in ViewModel code behind

public class UserAuthenticationPageModel : FreshBasePageModel
{
    public static UserAuthenticationPageModel Instance { get; private set; }
    public UserAuthenticationPageModel()
    {
        Instance = this;
    }

Modified code in FirebaseCloudNight

namespace iVanApp.Services { public class FirebaseCloudNight :
FirebaseCloudBaseHelper {

static public async Task<bool> SynchronizeNights()
{
    // Synchronize from Cloud to DB
    foreach (var cloudItem in cloudNights)
    {
        UserAuthenticationPageModel.Instance.CurrentProgress = currentNight / numberOfNights
        try
        { 
            //Here I removed code for retriving data from online DB
            currentNight   ;
        }
        catch (Exception ex)
        {
            return false;
        }
        return true;
    }
 }  }