[C#] Ditionary

MSDN 範例

補充 : 初始化值

new Ditionary<TKey,TValue>()
{
 {"xxx","xxx"},{"yyy","yyy"},
{"zzz","zzz"},{"aaa","aaa"}
}

1. using System;
2. using System.Collections.Generic;
4. public class Example
5. {
6.     public static void Main()
7.     {
8.         // Create a new dictionary of strings, with string keys.
9.         //
10.         Dictionary<string, string> openWith =
11.             new Dictionary<string, string>();
13.         // Add some elements to the dictionary. There are no
14.         // duplicate keys, but some of the values are duplicates.
15.         openWith.Add("txt", "notepad.exe");
16.         openWith.Add("bmp", "paint.exe");
17.         openWith.Add("dib", "paint.exe");
18.         openWith.Add("rtf", "wordpad.exe");
20.         // The Add method throws an exception if the new key is
21.         // already in the dictionary.
22.         try
23.         {
24.             openWith.Add("txt", "winword.exe");
25.         }
26.         catch (ArgumentException)
27.         {
28.             Console.WriteLine("An element with Key = \"txt\" already exists.");
29.         }
31.         // The Item property is another name for the indexer, so you
32.         // can omit its name when accessing elements.
33.         Console.WriteLine("For key = \"rtf\", value = {0}.",
34.             openWith["rtf"]);
36.         // The indexer can be used to change the value associated
37.         // with a key.
38.         openWith["rtf"] = "winword.exe";
39.         Console.WriteLine("For key = \"rtf\", value = {0}.",
40.             openWith["rtf"]);
42.         // If a key does not exist, setting the indexer for that key
43.         // adds a new key/value pair.
44.         openWith["doc"] = "winword.exe";
46.         // The indexer throws an exception if the requested key is
47.         // not in the dictionary.
48.         try
49.         {
50.             Console.WriteLine("For key = \"tif\", value = {0}.",
51.                 openWith["tif"]);
52.         }
53.         catch (KeyNotFoundException)
54.         {
55.             Console.WriteLine("Key = \"tif\" is not found.");
56.         }
58.         // When a program often has to try keys that turn out not to
59.         // be in the dictionary, TryGetValue can be a more efficient
60.         // way to retrieve values.
61.         string value = "";
62.         if (openWith.TryGetValue("tif", out value))
63.         {
64.             Console.WriteLine("For key = \"tif\", value = {0}.", value);
65.         }
66.         else
67.         {
68.             Console.WriteLine("Key = \"tif\" is not found.");
69.         }
71.         // ContainsKey can be used to test keys before inserting
72.         // them.
73.         if (!openWith.ContainsKey("ht"))
74.         {
75.             openWith.Add("ht", "hypertrm.exe");
76.             Console.WriteLine("Value added for key = \"ht\": {0}",
77.                 openWith["ht"]);
78.         }
80.         // When you use foreach to enumerate dictionary elements,
81.         // the elements are retrieved as KeyValuePair objects.
82.         Console.WriteLine();
83.         foreach( KeyValuePair<string, string> kvp in openWith )
84.         {
85.             Console.WriteLine("Key = {0}, Value = {1}",
86.                 kvp.Key, kvp.Value);
87.         }
89.         // To get the values alone, use the Values property.
90.         Dictionary<string, string>.ValueCollection valueColl =
91.             openWith.Values;
93.         // The elements of the ValueCollection are strongly typed
94.         // with the type that was specified for dictionary values.
95.         Console.WriteLine();
96.         foreach( string s in valueColl )
97.         {
98.             Console.WriteLine("Value = {0}", s);
99.         }
101.         // To get the keys alone, use the Keys property.
102.         Dictionary<string, string>.KeyCollection keyColl =
103.             openWith.Keys;
105.         // The elements of the KeyCollection are strongly typed
106.         // with the type that was specified for dictionary keys.
107.         Console.WriteLine();
108.         foreach( string s in keyColl )
109.         {
110.             Console.WriteLine("Key = {0}", s);
111.         }
113.         // Use the Remove method to remove a key/value pair.
114.         Console.WriteLine("\nRemove(\"doc\")");
115.         openWith.Remove("doc");
117.         if (!openWith.ContainsKey("doc"))
118.         {
119.             Console.WriteLine("Key \"doc\" is not found.");
120.         }
121.     }
122. }
124. /* This code example produces the following output:
126. An element with Key = "txt" already exists.
127. For key = "rtf", value = wordpad.exe.
128. For key = "rtf", value = winword.exe.
129. Key = "tif" is not found.
130. Key = "tif" is not found.
131. Value added for key = "ht": hypertrm.exe
133. Key = txt, Value = notepad.exe
134. Key = bmp, Value = paint.exe
135. Key = dib, Value = paint.exe
136. Key = rtf, Value = winword.exe
137. Key = doc, Value = winword.exe
138. Key = ht, Value = hypertrm.exe
140. Value = notepad.exe
141. Value = paint.exe
142. Value = paint.exe
143. Value = winword.exe
144. Value = winword.exe
145. Value = hypertrm.exe
147. Key = txt
148. Key = bmp
149. Key = dib
150. Key = rtf
151. Key = doc
152. Key = ht
154. Remove("doc")
155. Key "doc" is not found.
156.  */