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authorJason Smith <jason.smith@xamarin.com>2016-03-22 13:02:25 -0700
committerJason Smith <jason.smith@xamarin.com>2016-03-22 16:13:41 -0700
commit17fdde66d94155fc62a034fa6658995bef6fd6e5 (patch)
treeb5e5073a2a7b15cdbe826faa5c763e270a505729 /Xamarin.Forms.Core/BindingBase.cs
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Initial import
Diffstat (limited to 'Xamarin.Forms.Core/BindingBase.cs')
-rw-r--r--Xamarin.Forms.Core/BindingBase.cs111
1 files changed, 111 insertions, 0 deletions
diff --git a/Xamarin.Forms.Core/BindingBase.cs b/Xamarin.Forms.Core/BindingBase.cs
new file mode 100644
index 00000000..0810cbcf
--- /dev/null
+++ b/Xamarin.Forms.Core/BindingBase.cs
@@ -0,0 +1,111 @@
+using System;
+using System.Collections;
+using System.Runtime.CompilerServices;
+
+namespace Xamarin.Forms
+{
+ public abstract class BindingBase
+ {
+ static readonly ConditionalWeakTable<IEnumerable, CollectionSynchronizationContext> SynchronizedCollections = new ConditionalWeakTable<IEnumerable, CollectionSynchronizationContext>();
+
+ BindingMode _mode = BindingMode.Default;
+ string _stringFormat;
+
+ internal BindingBase()
+ {
+ }
+
+ public BindingMode Mode
+ {
+ get { return _mode; }
+ set
+ {
+ if (value != BindingMode.Default && value != BindingMode.OneWay && value != BindingMode.OneWayToSource && value != BindingMode.TwoWay)
+ throw new ArgumentException("mode is not a valid BindingMode", "mode");
+
+ ThrowIfApplied();
+
+ _mode = value;
+ }
+ }
+
+ public string StringFormat
+ {
+ get { return _stringFormat; }
+ set
+ {
+ ThrowIfApplied();
+
+ _stringFormat = value;
+ }
+ }
+
+ internal bool AllowChaining { get; set; }
+
+ internal object Context { get; set; }
+
+ internal bool IsApplied { get; private set; }
+
+ public static void DisableCollectionSynchronization(IEnumerable collection)
+ {
+ if (collection == null)
+ throw new ArgumentNullException("collection");
+
+ SynchronizedCollections.Remove(collection);
+ }
+
+ public static void EnableCollectionSynchronization(IEnumerable collection, object context, CollectionSynchronizationCallback callback)
+ {
+ if (collection == null)
+ throw new ArgumentNullException("collection");
+ if (callback == null)
+ throw new ArgumentNullException("callback");
+
+ SynchronizedCollections.Add(collection, new CollectionSynchronizationContext(context, callback));
+ }
+
+ protected void ThrowIfApplied()
+ {
+ if (IsApplied)
+ throw new InvalidOperationException("Can not change a binding while it's applied");
+ }
+
+ internal virtual void Apply(bool fromTarget)
+ {
+ IsApplied = true;
+ }
+
+ internal virtual void Apply(object context, BindableObject bindObj, BindableProperty targetProperty)
+ {
+ IsApplied = true;
+ }
+
+ internal abstract BindingBase Clone();
+
+ internal virtual object GetSourceValue(object value, Type targetPropertyType)
+ {
+ if (StringFormat != null)
+ return string.Format(StringFormat, value);
+
+ return value;
+ }
+
+ internal virtual object GetTargetValue(object value, Type sourcePropertyType)
+ {
+ return value;
+ }
+
+ internal static bool TryGetSynchronizedCollection(IEnumerable collection, out CollectionSynchronizationContext synchronizationContext)
+ {
+ if (collection == null)
+ throw new ArgumentNullException("collection");
+
+ return SynchronizedCollections.TryGetValue(collection, out synchronizationContext);
+ }
+
+ internal virtual void Unapply()
+ {
+ IsApplied = false;
+ }
+ }
+} \ No newline at end of file