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C#: Disable button during search/calculation

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梦如初夏
梦如初夏 2021-01-16 12:58

I have a search dialog where I want to disable the search button during the search. This is the current code but the button does not get deactivated

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  • 北恋
    北恋 (楼主)
    2021-01-16 13:42

    I've made an AsyncDelegateCommand for that reason (based on famous DelegateCommand), it internally disable command (in UI) during executing command action:

    public class AsyncDelegateCommand : ICommand
{
    readonly Action _execute;
    readonly Predicate _canExecute;
    bool _running;

    public event EventHandler CanExecuteChanged;

    public AsyncDelegateCommand(Action execute, Predicate canExecute = null)
    {
        _execute = execute;
        _canExecute = canExecute;
    }

    public bool CanExecute(object parameter)
    {
        return (_canExecute == null ? true : _canExecute(parameter)) && !_running;
    }

    public async void Execute(object parameter)
    {
        _running = true;
        Update();
        await Task.Run(() => _execute(parameter));
        _running = false;
        Update();
    }

    public void Update()
    {
        if (CanExecuteChanged != null)
            CanExecuteChanged(this, EventArgs.Empty);
    }
}



    xaml:
    


    


    ViewModel:
    


    AsyncDelegateCommand SomeCommand { get; }

    // in constructor
    SomeCommand = new AsyncDelegateCommand(o =>  { Thread.Sleep(5000); }); // code to run

    
    
    
             
    
                                                        
    
            
            
    
              
                
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