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authorE.Z. Hart <hartez@gmail.com>2016-09-26 18:09:58 -0600
committerJason Smith <jason.smith@xamarin.com>2016-09-27 11:02:54 -0700
commit1a86ca598e7af954a584226b1a7761ef3675d39e (patch)
tree75c0e5073cb342dcceac07c3782ca727dc9a9927 /Xamarin.Forms.Core/BindingExpression.cs
parentd9a550b408169580ae2bd0e5634d9fe2f46a8ccc (diff)
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Don't unsubscribe/resubscribe the listener to the same INPC
Diffstat (limited to 'Xamarin.Forms.Core/BindingExpression.cs')
-rw-r--r--Xamarin.Forms.Core/BindingExpression.cs9
1 files changed, 8 insertions, 1 deletions
diff --git a/Xamarin.Forms.Core/BindingExpression.cs b/Xamarin.Forms.Core/BindingExpression.cs
index 5ce8cd87..71ba0512 100644
--- a/Xamarin.Forms.Core/BindingExpression.cs
+++ b/Xamarin.Forms.Core/BindingExpression.cs
@@ -409,6 +409,7 @@ namespace Xamarin.Forms
class WeakPropertyChangedProxy
{
WeakReference _source, _listener;
+ internal WeakReference Source => _source;
public WeakPropertyChangedProxy(INotifyPropertyChanged source, PropertyChangedEventHandler listener)
{
@@ -470,7 +471,13 @@ namespace Xamarin.Forms
public void Subscribe(INotifyPropertyChanged handler)
{
- // If we're reapplying, we don't want to double subscribe
+ if (ReferenceEquals(handler, _listener?.Source?.Target))
+ {
+ // Already subscribed
+ return;
+ }
+
+ // Clear out the old subscription if necessary
Unsubscribe();
_listener = new WeakPropertyChangedProxy(handler, _changeHandler);