Pass command parameter to method in ViewModel in WPF

Question

I am trying to pass CommandParameter to the method in my ViewModel  How to do this   private void Open object sender        if  sender  this objMainWindow btnHistory                objMainWindow Container Child   objHistory             if  sender    this objMainWindow btnNew Item                objMainWindow Container Child   objNewItem             if  sender    this objMainWindow btnSide Effects                objMainWindow Container Child   objSideEffect            This is my meyhod in ViewModel that I want to pass CommandParameter  I use CommandParameter for button

User · Answer

If you are that particular to pass elements to viewmodel You can use   CommandParameter   Binding ElementName ManualParcelScanScreen

User · Answer

ViewModel  implies MVVM  If you re doing MVVM you shouldn t be passing views into your view models  Typically you do something like this in your XAML    lt Button Content  Edit           Command   Binding EditCommand           CommandParameter   Binding ViewModelItem    gt    And then this in your view model   private ViewModelItemType  ViewModelItem  public ViewModelItemType ViewModelItem       get               return this  ViewModelItem            set               this  ViewModelItem   value          RaisePropertyChanged      gt  this ViewModelItem            public ICommand EditCommand   get   return new RelayCommand lt ViewModelItemType gt  OnEdit       private void OnEdit ViewModelItemType itemToEdit            do something here        Obviously this is just to illustrate the point  if you only had one property to edit called ViewModelItem then you wouldn t need to pass it in as a command parameter

User · Answer

Try this   public class MyVmBase   INotifyPropertyChanged     private ICommand  clickCommand     public ICommand ClickCommand               get                       return  clickCommand      clickCommand   new CommandHandler  MyAction                                public void MyAction object message                if message    null                        Notify   quot Method  message  not defined quot                return                    switch  message ToString                          case  quot btnAdd quot                                         btnAdd Click                        break                                 case  quot BtnEdit Click quot                                         BtnEdit Click                        break                                 default                  throw new Exception   quot Method  message  not defined quot                    break                       public class CommandHandler   ICommand       private Action lt object gt   action      private Func lt object  bool gt   canExecute            lt summary gt          Creates instance of the command handler          lt  summary gt           lt param name  quot action quot  gt Action to be executed by the command lt  param gt           lt param name  quot canExecute quot  gt A bolean property to containing current permissions to execute the command lt  param gt      public CommandHandler Action lt object gt  action  Func lt object  bool gt  canExecute                if  action    null  throw new ArgumentNullException nameof action             action   action           canExecute   canExecute     x   gt  true             public CommandHandler Action lt object gt  action    this action  null                        lt summary gt          Wires CanExecuteChanged event           lt  summary gt      public event EventHandler CanExecuteChanged               add   CommandManager RequerySuggested    value            remove   CommandManager RequerySuggested -  value                    lt summary gt          Forcess checking if execute is allowed          lt  summary gt           lt param name  quot parameter quot  gt  lt  param gt           lt returns gt  lt  returns gt      public bool CanExecute object parameter                return  canExecute parameter              public void Execute object parameter                 action parameter             public void Refresh                 CommandManager InvalidateRequerySuggested             And in xaml        lt Button     Command  quot  Binding ClickCommand  quot      CommandParameter  quot BtnEdit Click quot   gt

User · Answer

Just using Data Binding syntax  For example    lt Button x Name  btn            Content  Click            Command   Binding ClickCmd             CommandParameter   Binding ElementName btn Path Content     gt     Not only can we use Data Binding to get some data from View Models  but also pass data back to View Models  In CommandParameter  must use ElementName to declare binding source explicitly

[c#] Pass command parameter to method in ViewModel in WPF?

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