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-rw-r--r--Xamarin.Forms.Core/Picker.cs54
1 files changed, 54 insertions, 0 deletions
diff --git a/Xamarin.Forms.Core/Picker.cs b/Xamarin.Forms.Core/Picker.cs
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+++ b/Xamarin.Forms.Core/Picker.cs
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+using System;
+using System.Collections.Generic;
+using System.Collections.Specialized;
+using Xamarin.Forms.Platform;
+
+namespace Xamarin.Forms
+{
+ [RenderWith(typeof(_PickerRenderer))]
+ public class Picker : View
+ {
+ public static readonly BindableProperty TitleProperty = BindableProperty.Create("Title", typeof(string), typeof(Picker), default(string));
+
+ public static readonly BindableProperty SelectedIndexProperty = BindableProperty.Create("SelectedIndex", typeof(int), typeof(Picker), -1, BindingMode.TwoWay,
+ propertyChanged: (bindable, oldvalue, newvalue) =>
+ {
+ EventHandler eh = ((Picker)bindable).SelectedIndexChanged;
+ if (eh != null)
+ eh(bindable, EventArgs.Empty);
+ }, coerceValue: CoerceSelectedIndex);
+
+ public Picker()
+ {
+ Items = new ObservableList<string>();
+ ((ObservableList<string>)Items).CollectionChanged += OnItemsCollectionChanged;
+ }
+
+ public IList<string> Items { get; }
+
+ public int SelectedIndex
+ {
+ get { return (int)GetValue(SelectedIndexProperty); }
+ set { SetValue(SelectedIndexProperty, value); }
+ }
+
+ public string Title
+ {
+ get { return (string)GetValue(TitleProperty); }
+ set { SetValue(TitleProperty, value); }
+ }
+
+ public event EventHandler SelectedIndexChanged;
+
+ static object CoerceSelectedIndex(BindableObject bindable, object value)
+ {
+ var picker = (Picker)bindable;
+ return picker.Items == null ? -1 : ((int)value).Clamp(-1, picker.Items.Count - 1);
+ }
+
+ void OnItemsCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
+ {
+ SelectedIndex = SelectedIndex.Clamp(-1, Items.Count - 1);
+ }
+ }
+} \ No newline at end of file