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SortedDictionary<TKey, TValue> Constructor (IDictionary<TKey, TValue>, IComparer<TKey>)

Initializes a new instance of the SortedDictionary<TKey, TValue> class that contains elements copied from the specified IDictionary<TKey, TValue> and uses the specified IComparer<T> implementation to compare keys.

Namespace:  System.Collections.Generic
Assemblies:   System (in System.dll)
  System.Collections (in System.Collections.dll)

public SortedDictionary(
	IDictionary<TKey, TValue> dictionary,
	IComparer<TKey> comparer
)

Parameters

dictionary
Type: System.Collections.Generic.IDictionary<TKey, TValue>

The IDictionary<TKey, TValue> whose elements are copied to the new SortedDictionary<TKey, TValue>.

comparer
Type: System.Collections.Generic.IComparer<TKey>

The IComparer<T> implementation to use when comparing keys, or null to use the default Comparer<T> for the type of the key.

ExceptionCondition
ArgumentNullException

dictionary is null.

ArgumentException

dictionary contains one or more duplicate keys.

Every key in a SortedDictionary<TKey, TValue> must be unique according to the specified comparer; therefore, every key in the source dictionary must also be unique according to the specified comparer.

SortedDictionary<TKey, TValue> requires a comparer implementation to perform key comparisons. If comparer is null, this constructor uses the default generic equality comparer, Comparer<T>.Default. If type TKey implements the System.IComparable<T> generic interface, the default comparer uses that implementation.

This constructor is an O(n log n) operation, where n is the number of elements in dictionary.

The following code example shows how to use SortedDictionary<TKey, TValue> to create a case-insensitive sorted copy of the information in a case-insensitive Dictionary<TKey, TValue>, by passing the Dictionary<TKey, TValue> to the SortedDictionary<TKey, TValue>(IDictionary<TKey, TValue>, IComparer<TKey>) constructor. In this example, the case-insensitive comparers are for the current culture.

using System;
using System.Collections.Generic;

public class Example
{
    public static void Main()
    {
        // Create a new Dictionary of strings, with string keys and 
        // a case-insensitive equality comparer for the current  
        // culture.
        Dictionary<string, string> openWith = 
            new Dictionary<string, string>
                (StringComparer.CurrentCultureIgnoreCase);

        // Add some elements to the dictionary. 
        openWith.Add("txt", "notepad.exe");
        openWith.Add("Bmp", "paint.exe");
        openWith.Add("DIB", "paint.exe");
        openWith.Add("rtf", "wordpad.exe");

        // List the contents of the Dictionary.
        Console.WriteLine();
        foreach( KeyValuePair<string, string> kvp in openWith)
        {
            Console.WriteLine("Key = {0}, Value = {1}", kvp.Key, 
                kvp.Value);
        }

        // Create a SortedDictionary of strings with string keys and a  
        // case-insensitive equality comparer for the current culture, 
        // and initialize it with the contents of the Dictionary.
        SortedDictionary<string, string> copy = 
                    new SortedDictionary<string, string>(openWith, 
                        StringComparer.CurrentCultureIgnoreCase);

        // List the sorted contents of the copy.
        Console.WriteLine();
        foreach( KeyValuePair<string, string> kvp in copy )
        {
            Console.WriteLine("Key = {0}, Value = {1}", kvp.Key, 
                kvp.Value);
        }
    }
}

/* This code example produces the following output:

Key = txt, Value = notepad.exe
Key = Bmp, Value = paint.exe
Key = DIB, Value = paint.exe
Key = rtf, Value = wordpad.exe

Key = Bmp, Value = paint.exe
Key = DIB, Value = paint.exe
Key = rtf, Value = wordpad.exe
Key = txt, Value = notepad.exe
 */

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8
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