/// <summary>
/// Find nearby items within a parent element
/// <para>For example, a Button may have a Textbox nearby it in the same Grid, and this can find that</para>
/// </summary>
/// <typeparam name="T">Type of element to find nearby</typeparam>
/// <typeparam name="TParentType">Type of the Parent element to search within</typeparam>
/// <param name="fromEl">Element to find the other nearby element from</param>
/// <returns>The nearby elements</returns>
public static IEnumerable <T> FindAllNear <T, TParentType>(UIElement fromEl)
where T : UIElement
where TParentType : UIElement
{
if (fromEl != null)
{
var parent = UIElementHelper.FindParentOf <TParentType>(fromEl);
if (parent != null)
{
return(UIElementHelper.GetChildren <T>(parent));
}
}
return(Enumerable.Empty <T>());
}
/// <summary>
/// Find a nearby item within a parent item
/// <para>For example, a Button may have a Textbox nearby it in the same Grid, and this can find that</para>
/// </summary>
/// <typeparam name="T">Type of element to find nearby</typeparam>
/// <typeparam name="TParentType">Type of the Parent element to search within</typeparam>
/// <param name="fromEl">Element to find the other nearby element from</param>
/// <returns>The nearby element, or null if none found</returns>
public static T FindNear <T, TParentType>(UIElement fromEl)
where T : UIElement
where TParentType : UIElement
{
if (fromEl != null)
{
var grid = UIElementHelper.FindParentOf <TParentType>(fromEl);
if (grid != null)
{
var near = UIElementHelper.GetChild <T>(grid);
if (near != null)
{
return(near);
}
}
}
return(null);
}
/// <summary>
/// Setup for appropriate handling of Disposable View Models in WPF
/// <para>If used on a Window, will attach to Closed and Dispatcher.ShutdownStarted events to dispose of ViewModel</para>
/// <para>If used on other UIElement, will search for parent Window in the Visual Tree and attach to that window's events</para>
/// <para>If used on any other object, nothing will happen</para>
/// </summary>
/// <param name="fe">FrameworkElement object to attach to for Disposing of ViewModel (DataContext)</param>
public static void HandleDisposableViewModel(this FrameworkElement fe)
{
Action Dispose = () =>
{
var DataContext = fe.DataContext as IDisposable;
if (DataContext != null)
{
DataContext.Dispose();
}
};
var win = fe as Window;
if (win == null)
{
var ctrl = fe as UIElement;
if (ctrl != null)
{
win = UIElementHelper.FindParentOf <Window>(ctrl);
}
}
if (win != null)
{
EventHandler WinClosed = null;
EventHandler ShutdownStarted = null;
WinClosed = (sender, e) =>
{
Dispose();
win.Dispatcher.ShutdownStarted -= ShutdownStarted;
win.Closed -= WinClosed;
};
ShutdownStarted = (sender, e) =>
{
Dispose();
win.Closed -= WinClosed;
win.Dispatcher.ShutdownStarted -= ShutdownStarted;
};
win.Closed += WinClosed;
win.Dispatcher.ShutdownStarted += ShutdownStarted;
}
}
