C# 8 and .NET Core 3 Projects Using Azure - Second Edition

RelayCommandAsync

The code for RelayCommandAsync is not too onerous. We implement an interface called ICommand, which has just two methods. A bare-bones implementation of ICommand would look like this:

public class RelayCommandAsync<T> : ICommand
{ 
    public bool CanExecute(object parameter)
    {
    }
 
    public void Execute(object parameter)
    {
    } 
}

Clearly, this does nothing, so let's fill in those methods. We'll start with Execute; we need to pass an action into the Execute method, and we can do that through the constructor:

public class RelayCommandAsync<T> : ICommand
{
    readonly Func<T, Task> _execute = null;
 
    public RelayCommandAsync(Func<T, Task> execute)
    {
        if (execute == null)
            throw new ArgumentNullException("execute");
 
        _execute = execute;
    }
 
    public ...