/// <summary>Registers a frame so that its navigation state can be saved and restored. </summary>
/// <param name="frame">The frame. </param>
/// <param name="sessionStateKey">The session state key. </param>
public static void RegisterFrame(MtFrame frame, String sessionStateKey)
{
if (frame.GetValue(FrameSessionStateKeyProperty) != null)
{
throw new InvalidOperationException("Frames can only be registered to one session state key");
}
if (frame.GetValue(FrameSessionStateProperty) != null)
{
throw new InvalidOperationException("Frames must be either be registered before accessing frame session state, or not registered at all");
}
frame.SetValue(FrameSessionStateKeyProperty, sessionStateKey);
_registeredFrames.Add(new WeakReference <MtFrame>(frame));
RestoreFrameNavigationState(frame);
}
/// <summary>Deregisters a frame. </summary>
/// <param name="frame">The frame. </param>
public static void DeregisterFrame(MtFrame frame)
{
SessionState.Remove((String)frame.GetValue(FrameSessionStateKeyProperty));
_registeredFrames.RemoveAll((weakFrameReference) =>
{
MtFrame testFrame;
return(!weakFrameReference.TryGetTarget(out testFrame) || testFrame == frame);
});
}
/// <summary>Gets the session state for a given frame. </summary>
/// <param name="frame">The frame. </param>
/// <returns>The session state. </returns>
public static Dictionary <String, Object> SessionStateForFrame(MtFrame frame)
{
var frameState = (Dictionary <String, Object>)frame.GetValue(FrameSessionStateProperty);
if (frameState == null)
{
var frameSessionKey = (String)frame.GetValue(FrameSessionStateKeyProperty);
if (frameSessionKey != null)
{
if (!_sessionState.ContainsKey(frameSessionKey))
{
_sessionState[frameSessionKey] = new Dictionary <String, Object>();
}
frameState = (Dictionary <String, Object>)_sessionState[frameSessionKey];
}
else
{
frameState = new Dictionary <String, Object>();
}
frame.SetValue(FrameSessionStateProperty, frameState);
}
return(frameState);
}
/// <summary>Registers a frame so that its navigation state can be saved and restored. </summary>
/// <param name="frame">The frame. </param>
/// <param name="sessionStateKey">The session state key. </param>
public static void RegisterFrame(MtFrame frame, String sessionStateKey)
{
if (frame.GetValue(FrameSessionStateKeyProperty) != null)
throw new InvalidOperationException("Frames can only be registered to one session state key");
if (frame.GetValue(FrameSessionStateProperty) != null)
throw new InvalidOperationException("Frames must be either be registered before accessing frame session state, or not registered at all");
frame.SetValue(FrameSessionStateKeyProperty, sessionStateKey);
_registeredFrames.Add(new WeakReference<MtFrame>(frame));
RestoreFrameNavigationState(frame);
}
/// <summary>Gets the session state for a given frame. </summary>
/// <param name="frame">The frame. </param>
/// <returns>The session state. </returns>
public static Dictionary<String, Object> SessionStateForFrame(MtFrame frame)
{
var frameState = (Dictionary<String, Object>)frame.GetValue(FrameSessionStateProperty);
if (frameState == null)
{
var frameSessionKey = (String)frame.GetValue(FrameSessionStateKeyProperty);
if (frameSessionKey != null)
{
if (!_sessionState.ContainsKey(frameSessionKey))
_sessionState[frameSessionKey] = new Dictionary<String, Object>();
frameState = (Dictionary<String, Object>)_sessionState[frameSessionKey];
}
else
frameState = new Dictionary<String, Object>();
frame.SetValue(FrameSessionStateProperty, frameState);
}
return frameState;
}
/// <summary>Deregisters a frame. </summary>
/// <param name="frame">The frame. </param>
public static void DeregisterFrame(MtFrame frame)
{
SessionState.Remove((String)frame.GetValue(FrameSessionStateKeyProperty));
_registeredFrames.RemoveAll((weakFrameReference) =>
{
MtFrame testFrame;
return !weakFrameReference.TryGetTarget(out testFrame) || testFrame == frame;
});
}
