public MaterialItemListViewModel()
{
AddMaterialCommand = new AppCommand(ShowAddMaterialDialog, CanAddItem);
AddGemCommand = new AppCommand(ShowAddGemDialog, CanAddItem);
EditItemCommand = new AppCommand(ShowEditDialog, CanEditItem);
CopyItemCommand = new AppCommand(ProcessCopy, CanCopyItem);
DeleteItemCommand = new AppCommand(ProcessDelete);
ItemList.CollectionChanged += (sender, e) =>
{
AddMaterialCommand.RaiseCanExecuteChanged();
AddGemCommand.RaiseCanExecuteChanged();
CopyItemCommand.RaiseCanExecuteChanged();
};
}