summaryrefslogtreecommitdiff
path: root/Xamarin.Forms.Core/ResourceDictionary.cs
blob: c9413eb3e414d295a8a49af2a1b798111a704b74 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
using System;
using System.Collections;
using System.Collections.Generic;
using System.Runtime.CompilerServices;
using System.Linq;
using System.Reflection;
using Xamarin.Forms.Internals;

namespace Xamarin.Forms
{
	public class ResourceDictionary : IResourceDictionary, IDictionary<string, object>
	{
		static ConditionalWeakTable<Type, ResourceDictionary> s_instances = new ConditionalWeakTable<Type, ResourceDictionary>();
		readonly Dictionary<string, object> _innerDictionary = new Dictionary<string, object>();

		Type _mergedWith;
		[TypeConverter (typeof(TypeTypeConverter))]
		public Type MergedWith {
			get { return _mergedWith; }
			set { 
				if (_mergedWith == value)
					return;

				if (!typeof(ResourceDictionary).GetTypeInfo().IsAssignableFrom(value.GetTypeInfo()))
					throw new ArgumentException("MergedWith should inherit from ResourceDictionary");

				_mergedWith = value;
				if (_mergedWith == null)
					return;

				_mergedInstance = s_instances.GetValue(_mergedWith,(key) => (ResourceDictionary)Activator.CreateInstance(key));
				OnValuesChanged (_mergedInstance.ToArray());
			}
		}

		ResourceDictionary _mergedInstance;

		void ICollection<KeyValuePair<string, object>>.Add(KeyValuePair<string, object> item)
		{
			((ICollection<KeyValuePair<string, object>>)_innerDictionary).Add(item);
			OnValuesChanged(item);
		}

		public void Clear()
		{
			_innerDictionary.Clear();
		}

		bool ICollection<KeyValuePair<string, object>>.Contains(KeyValuePair<string, object> item)
		{
			return ((ICollection<KeyValuePair<string, object>>)_innerDictionary).Contains(item);
		}

		void ICollection<KeyValuePair<string, object>>.CopyTo(KeyValuePair<string, object>[] array, int arrayIndex)
		{
			((ICollection<KeyValuePair<string, object>>)_innerDictionary).CopyTo(array, arrayIndex);
		}

		public int Count
		{
			get { return _innerDictionary.Count; }
		}

		bool ICollection<KeyValuePair<string, object>>.IsReadOnly
		{
			get { return ((ICollection<KeyValuePair<string, object>>)_innerDictionary).IsReadOnly; }
		}

		bool ICollection<KeyValuePair<string, object>>.Remove(KeyValuePair<string, object> item)
		{
			return ((ICollection<KeyValuePair<string, object>>)_innerDictionary).Remove(item);
		}

		public void Add(string key, object value)
		{
			if (ContainsKey(key))
				throw new ArgumentException($"A resource with the key '{key}' is already present in the ResourceDictionary.");
			_innerDictionary.Add(key, value);
			OnValueChanged(key, value);
		}

		public bool ContainsKey(string key)
		{
			return _innerDictionary.ContainsKey(key);
		}

		[IndexerName("Item")]
		public object this[string index]
		{
			get
			{
				if (_innerDictionary.ContainsKey(index))
					return _innerDictionary[index];
				throw new KeyNotFoundException($"The resource '{index}' is not present in the dictionary.");
			}
			set
			{
				_innerDictionary[index] = value;
				OnValueChanged(index, value);
			}
		}

		public ICollection<string> Keys
		{
			get { return _innerDictionary.Keys; }
		}

		public bool Remove(string key)
		{
			return _innerDictionary.Remove(key);
		}

		public ICollection<object> Values
		{
			get { return _innerDictionary.Values; }
		}

		IEnumerator IEnumerable.GetEnumerator()
		{
			return GetEnumerator();
		}

		public IEnumerator<KeyValuePair<string, object>> GetEnumerator()
		{
			return _innerDictionary.GetEnumerator();
		}

		internal IEnumerable<KeyValuePair<string, object>> MergedResources {
			get {
				if (_mergedInstance != null)
					foreach (var r in _mergedInstance.MergedResources)
						yield return r;
				foreach (var r in _innerDictionary)
					yield return r;
			}
		}

		public bool TryGetValue(string key, out object value)
		{
			return _innerDictionary.TryGetValue(key, out value);
		}

		internal bool TryGetMergedValue(string key, out object value)
		{
			return _innerDictionary.TryGetValue(key, out value) || (_mergedInstance != null && _mergedInstance.TryGetValue(key, out value));
		}

		event EventHandler<ResourcesChangedEventArgs> IResourceDictionary.ValuesChanged
		{
			add { ValuesChanged += value; }
			remove { ValuesChanged -= value; }
		}

		public void Add(Style style)
		{
			if (string.IsNullOrEmpty(style.Class))
				Add(style.TargetType.FullName, style);
			else
			{
				IList<Style> classes;
				object outclasses;
				if (!TryGetValue(Style.StyleClassPrefix + style.Class, out outclasses) || (classes = outclasses as IList<Style>) == null)
					classes = new List<Style>();
				classes.Add(style);
				this[Style.StyleClassPrefix + style.Class] = classes;
			}
		}

		void OnValueChanged(string key, object value)
		{
			OnValuesChanged(new KeyValuePair<string, object>(key, value));
		}

		void OnValuesChanged(params KeyValuePair<string, object>[] values)
		{
			if (values == null || values.Length == 0)
				return;
			ValuesChanged?.Invoke(this, new ResourcesChangedEventArgs(values));
		}

		event EventHandler<ResourcesChangedEventArgs> ValuesChanged;
	}
}