What would be the appropriate method for view models in a C# WPF project?

Question

Hello

I created record insertion and update view models in my c# wpf project. These view models have common save and cancel commands. When the save command is clicked, it calls the save function from the relevant service and if there are any error conditions, it catches them in the view model and prints them.

Since these are common to all of them, would it be a correct approach to create a single basic view model, define the common commands as public, define the error checkers here and use them by inheriting them in the relevant view model?

Can you share the most correct method with me in this regard?

Thank you.

Answer 1

Hi, @fatih uyanık. Welcome to Microsoft Q&A. 

It is a correct approach to define common commands in the BaseViewModel and inherit them from the ChildViewModel, which could reduce duplicate code and improve the maintainability of the program.

Here is a simple example(Assuming it is an MVVM project): Install CommunityToolkit.Mvvm via NuGet

BaseViewModel.cs

    public class BaseViewModel:ObservableObject
    {
        public RelayCommand saveCommand {  get; set; }

        public RelayCommand cancelCommand { get; set; }

        public BaseViewModel() { 
            saveCommand = new RelayCommand(Save);
            cancelCommand = new RelayCommand(Cancel);
        }

        public void Save() {
            //TODO Save related services
            MessageBox.Show("Save Complete");
        }

        public void Cancel()
        {
            //TODO Cancel related services
            MessageBox.Show("Cancel Complete");
        }
    }

MainViewModel.cs(Here as a child ViewModel)

    public class MainViewModel:BaseViewModel
    {
        public MainViewModel():base() {

        }
    }

MainWindow.xaml

    <Grid>
        <Grid.DataContext>
            <vm:MainViewModel></vm:MainViewModel>
        </Grid.DataContext>
        <Button Content="Save" Command="{Binding saveCommand}" Width="200" Height="50" ></Button>
        <Button Content="Cancel" Command="{Binding cancelCommand}" Width="200" Height="50" Margin="0,200,0,0"></Button>
    </Grid>

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