Visibility of StackPanel in MVVM - wpf

Question

I'm working with WPF using Prism ( MVVM). I wanted to set visibililty
of StackPanel from ViewModel calss. The StackPanel's visibility is
binded like :
<StackPanel x:Name="spVisibility" Orientation="Horizontal"
Visibility="{Binding spVisibility, Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}">
I've view model class like :
public class SearchId : BindableBase, INotifyPropertyChanged
{
private Visibility _visibility = Visibility.Collapsed;
private DelegateCommand<object> searchCommand;
public event PropertyChangedEventHandler PropertyChanged;
public SearchId()
{
searchCommand = new DelegateCommand<object>(this.SearchData);
}///
public Visibility spVisibility
{
get { return _visibility; }
set
{
if (!string.Equals(_visibility, value))
{
_visibility = value;
RaisePropertyChanged("spVisibility");
}
}
}
private void RaisePropertyChanged(string propertyName)
{
if (PropertyChanged != null)
{
PropertyChanged(this,
new PropertyChangedEventArgs (propertyName));
}
}
private async void SearchData(object parameter)
{
_visibility = Visibility.Visible;
}
}
But this not working. Please help me.

Answer 1

_visibility = Visibility.Visible is setting the private property instead of using the public one so RaisePropertyChanged("spVisibility") is being bypassed. You need to use spVisibility = Visibility.Visible.

Answer 2

If you are using MVVM i would recommend using a Boolean value instead of Visibility. The whole purpose of MVVM is seperation of View Logic from DataLogic.
View logic:
<StackPanel Orientation="Horizontal"
Visibility="{Binding ShowStackPanel, Converter={StaticResource BooleanToVisibilityConverter}}">
Use a Converter to convert the boolan to a Visibility Property.. BooleanToVisibilityConverter is part of .NET and can be referenced without defining it manually in the xaml.
public class SearchId : BindableBase, INotifyPropertyChanged
{
private bool _showStackPanel;
private DelegateCommand<object> searchCommand;
public event PropertyChangedEventHandler PropertyChanged;
public SearchByIDVM()
{
searchCommand = new DelegateCommand<object>(this.SearchData);
}///
public bool ShowStackPanel
{
get { return _showStackPanel; }
set
{
if (!Equals(_showStackPanel, value))
{
_showStackPanel= value;
RaisePropertyChanged("ShowStackPanel");
}
}
}
private void RaisePropertyChanged(string propertyName)
{
if (PropertyChanged != null)
{
PropertyChanged(this,
new PropertyChangedEventArgs (propertyName));
}
}
private async void SearchData(object parameter)
{
ShowStackPanel= true;
}
}