Fix code snippet fragmentation in Dictionary documentation (#12148)

Author: Copilot

snippets/csharp/System.Collections.Generic/DictionaryTKey,TValue/System.Collections.IDictionary.Contains/Project.csproj

@@ -0,0 +1,8 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Library</OutputType>
+    <TargetFramework>net10.0</TargetFramework>
+  </PropertyGroup>
+   
+</Project>

snippets/csharp/System.Collections.Generic/DictionaryTKey,TValue/System.Collections.IDictionary.Contains/source.cs

@@ -0,0 +1,35 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+
+public class Example
+{
+    public static void Main()
+    {
+        // Create a new dictionary of strings, with string keys,
+        // and access it using the IDictionary interface.
+        //
+        IDictionary openWith = new Dictionary<string, string>();
+
+        // Add some elements to the dictionary. There are no
+        // duplicate keys, but some of the values are duplicates.
+        // IDictionary.Add throws an exception if incorrect types
+        // are supplied for key or value.
+        openWith.Add("txt", "notepad.exe");
+        openWith.Add("bmp", "paint.exe");
+        openWith.Add("dib", "paint.exe");
+        openWith.Add("rtf", "wordpad.exe");
+
+        // Contains can be used to test keys before inserting
+        // them.
+        if (!openWith.Contains("ht"))
+        {
+            openWith.Add("ht", "hypertrm.exe");
+            Console.WriteLine($"""Value added for key = "ht": {openWith["ht"]}""");
+        }
+
+        // IDictionary.Contains returns false if the wrong data
+        // type is supplied.
+        Console.WriteLine($"openWith.Contains(29.7) returns {openWith.Contains(29.7)}");
+    }
+}

snippets/csharp/System.Collections.Generic/DictionaryTKey,TValue/System.Collections.IDictionary.GetEnumerator/Project.csproj

@@ -0,0 +1,8 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Library</OutputType>
+    <TargetFramework>net10.0</TargetFramework>
+  </PropertyGroup>
+   
+</Project>

snippets/csharp/System.Collections.Generic/DictionaryTKey,TValue/System.Collections.IDictionary.GetEnumerator/source.cs

@@ -0,0 +1,31 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+
+public class Example
+{
+    public static void Main()
+    {
+        // Create a new dictionary of strings, with string keys,
+        // and access it using the IDictionary interface.
+        //
+        IDictionary openWith = new Dictionary<string, string>();
+
+        // Add some elements to the dictionary. There are no
+        // duplicate keys, but some of the values are duplicates.
+        // IDictionary.Add throws an exception if incorrect types
+        // are supplied for key or value.
+        openWith.Add("txt", "notepad.exe");
+        openWith.Add("bmp", "paint.exe");
+        openWith.Add("dib", "paint.exe");
+        openWith.Add("rtf", "wordpad.exe");
+
+        // When you use foreach to enumerate dictionary elements
+        // with the IDictionary interface, the elements are retrieved
+        // as DictionaryEntry objects instead of KeyValuePair objects.
+        foreach( DictionaryEntry de in openWith )
+        {
+            Console.WriteLine($"Key = {de.Key}, Value = {de.Value}");
+        }
+    }
+}

snippets/csharp/System.Collections.Generic/DictionaryTKey,TValue/System.Collections.IDictionary.Item/Project.csproj

@@ -0,0 +1,8 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Library</OutputType>
+    <TargetFramework>net10.0</TargetFramework>
+  </PropertyGroup>
+   
+</Project>

snippets/csharp/System.Collections.Generic/DictionaryTKey,TValue/System.Collections.IDictionary.Item/source.cs

@@ -0,0 +1,59 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+
+public class Example
+{
+    public static void Main()
+    {
+        // Create a new dictionary of strings, with string keys,
+        // and access it using the IDictionary interface.
+        //
+        IDictionary openWith = new Dictionary<string, string>();
+
+        // Add some elements to the dictionary. There are no
+        // duplicate keys, but some of the values are duplicates.
+        // IDictionary.Add throws an exception if incorrect types
+        // are supplied for key or value.
+        openWith.Add("txt", "notepad.exe");
+        openWith.Add("bmp", "paint.exe");
+        openWith.Add("dib", "paint.exe");
+        openWith.Add("rtf", "wordpad.exe");
+
+        // The Item property is another name for the indexer, so you
+        // can omit its name when accessing elements.
+        Console.WriteLine($"""For key = "rtf", value = {openWith["rtf"]}.""");
+
+        // The indexer can be used to change the value associated
+        // with a key.
+        openWith["rtf"] = "winword.exe";
+        Console.WriteLine($"""For key = "rtf", value = {openWith["rtf"]}.""");
+
+        // If a key does not exist, setting the indexer for that key
+        // adds a new key/value pair.
+        openWith["doc"] = "winword.exe";
+
+        // The indexer returns null if the key is of the wrong data
+        // type.
+        Console.WriteLine("The indexer returns null"
+            + " if the key is of the wrong type:");
+        Console.WriteLine($"For key = 2, value = {openWith[2]}.");
+
+        // The indexer throws an exception when setting a value
+        // if the key is of the wrong data type.
+        try
+        {
+            openWith[2] = "This does not get added.";
+        }
+        catch (ArgumentException)
+        {
+            Console.WriteLine("A key of the wrong type was specified"
+                + " when assigning to the indexer.");
+        }
+
+        // Unlike the default Item property on the Dictionary class
+        // itself, IDictionary.Item does not throw an exception
+        // if the requested key is not in the dictionary.
+        Console.WriteLine($"""For key = "tif", value = {openWith["tif"]}.""");
+    }
+}

snippets/csharp/System.Collections.Generic/DictionaryTKey,TValue/System.Collections.IDictionary.Keys/Project.csproj

@@ -0,0 +1,8 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Library</OutputType>
+    <TargetFramework>net10.0</TargetFramework>
+  </PropertyGroup>
+   
+</Project>

snippets/csharp/System.Collections.Generic/DictionaryTKey,TValue/System.Collections.IDictionary.Keys/source.cs

@@ -0,0 +1,45 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+
+public class Example
+{
+    public static void Main()
+    {
+        // Create a new dictionary of strings, with string keys,
+        // and access it using the IDictionary interface.
+        //
+        IDictionary openWith = new Dictionary<string, string>();
+
+        // Add some elements to the dictionary. There are no
+        // duplicate keys, but some of the values are duplicates.
+        // IDictionary.Add throws an exception if incorrect types
+        // are supplied for key or value.
+        openWith.Add("txt", "notepad.exe");
+        openWith.Add("bmp", "paint.exe");
+        openWith.Add("dib", "paint.exe");
+        openWith.Add("rtf", "wordpad.exe");
+
+        // To get the keys alone, use the Keys property.
+        ICollection icoll = openWith.Keys;
+
+        // The elements of the collection are strongly typed
+        // with the type that was specified for dictionary keys,
+        // even though the ICollection interface is not strongly
+        // typed.
+        Console.WriteLine();
+        foreach( string s in icoll )
+        {
+            Console.WriteLine($"Key = {s}");
+        }
+
+        // When you use foreach to enumerate dictionary elements
+        // with the IDictionary interface, the elements are retrieved
+        // as DictionaryEntry objects instead of KeyValuePair objects.
+        Console.WriteLine();
+        foreach( DictionaryEntry de in openWith )
+        {
+            Console.WriteLine($"Key = {de.Key}, Value = {de.Value}");
+        }
+    }
+}

snippets/csharp/System.Collections.Generic/DictionaryTKey,TValue/System.Collections.IDictionary.Remove/Project.csproj

@@ -0,0 +1,8 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Library</OutputType>
+    <TargetFramework>net10.0</TargetFramework>
+  </PropertyGroup>
+   
+</Project>

snippets/csharp/System.Collections.Generic/DictionaryTKey,TValue/System.Collections.IDictionary.Remove/source.cs

@@ -0,0 +1,33 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+
+public class Example
+{
+    public static void Main()
+    {
+        // Create a new dictionary of strings, with string keys,
+        // and access it using the IDictionary interface.
+        //
+        IDictionary openWith = new Dictionary<string, string>();
+
+        // Add some elements to the dictionary. There are no
+        // duplicate keys, but some of the values are duplicates.
+        // IDictionary.Add throws an exception if incorrect types
+        // are supplied for key or value.
+        openWith.Add("txt", "notepad.exe");
+        openWith.Add("bmp", "paint.exe");
+        openWith.Add("dib", "paint.exe");
+        openWith.Add("rtf", "wordpad.exe");
+
+        // Use the Remove method to remove a key/value pair. No
+        // exception is thrown if the wrong data type is supplied.
+        Console.WriteLine($"""{"\n"}Remove("dib")""");
+        openWith.Remove("dib");
+
+        if (!openWith.Contains("dib"))
+        {
+            Console.WriteLine("""Key "dib" is not found.""");
+        }
+    }
+}