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.

Answer 1

"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:

<Button Content="Edit"          Command="{Binding EditCommand}"         CommandParameter="{Binding ViewModelItem}" > 

And then this in your view model:

private ViewModelItemType _ViewModelItem; public ViewModelItemType ViewModelItem {     get     {         return this._ViewModelItem;     }     set     {         this._ViewModelItem = value;         RaisePropertyChanged(() => this.ViewModelItem);     } }  public ICommand EditCommand { get { return new RelayCommand<ViewModelItemType>(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.