Enable/Disable Button in UserControl

Question

I have a Button in a UserControl that works just fine.

I expected the Button to be enabled/disabled like in a "normal" ContentView/ContentPage, setting the CanExecute-Method in my ViewModel to true or false.

But this is not working at all.

I tried to google it, but have not found any answers...

Any ideas ?

Answer 1

Hello,​

Welcome to our Microsoft Q&A platform!

I expected the Button to be enabled/disabled like in a "normal" ContentView/ContentPage, setting the CanExecute-Method in my ViewModel to true or false.

To change the status of the command's 'CanExecute', try using Command(Action, Func<Boolean>) constructor method. The second parameter indicates if the Command can be executed. Create a 'bool' property in the model class and then call Command.ChangeCanExecute method when the property is changed.

Here the sample code you could refer to:

   public class MainPageModel : INotifyPropertyChanged  
   {  
       public Command BtnCommand { get; set; }  
     
     
       public MainPageModel()  
       {  
           BtnCommand = new Command(() =>  
           {  
               App.Current.MainPage.DisplayAlert("title", "message", "cancel");  
           }, () => IsBtnEnabled);  
       }  
     
       private bool isBtnEnabled;  
       public bool IsBtnEnabled  
       {  
           get  
           {  
               return isBtnEnabled;  
           }  
           set  
           {  
               if (isBtnEnabled != value)  
               {  
                   isBtnEnabled = value;  
                   BtnCommand.ChangeCanExecute(); //  
                   NotifyPropertyChanged();  
               }  
           }  
       }  
     
       protected virtual void NotifyPropertyChanged([CallerMemberName] string propertyName = "")  
       {  
           PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));  
       }  
       public event PropertyChangedEventHandler PropertyChanged;  
   }  

You could set binding to the button's IsEnabled property to enable/disable the button directly.

   Button Command="{Binding ClickCommand}" IsEnabled="{Binding IsBtnEnabled}"/>  

Best Regards,

Jarvan Zhang

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