SortedList<TKey,TValue> Constructors

Definition

Namespace:

System.Collections.Generic

Assemblies:

netstandard.dll, System.Collections.dll

Initializes a new instance of the SortedList<TKey,TValue> class.

Overloads

SortedList<TKey,TValue>()	Initializes a new instance of the SortedList<TKey,TValue> class that is empty, has the default initial capacity, and uses the default IComparer<T>.
SortedList<TKey,TValue>(IComparer<TKey>)	Initializes a new instance of the SortedList<TKey,TValue> class that is empty, has the default initial capacity, and uses the specified IComparer<T>.
SortedList<TKey,TValue>(IDictionary<TKey,TValue>)	Initializes a new instance of the SortedList<TKey,TValue> class that contains elements copied from the specified IDictionary<TKey,TValue>, has sufficient capacity to accommodate the number of elements copied, and uses the default IComparer<T>.
SortedList<TKey,TValue>(Int32)	Initializes a new instance of the SortedList<TKey,TValue> class that is empty, has the specified initial capacity, and uses the default IComparer<T>.
SortedList<TKey,TValue>(IDictionary<TKey,TValue>, IComparer<TKey>)	Initializes a new instance of the SortedList<TKey,TValue> class that contains elements copied from the specified IDictionary<TKey,TValue>, has sufficient capacity to accommodate the number of elements copied, and uses the specified IComparer<T>.
SortedList<TKey,TValue>(Int32, IComparer<TKey>)	Initializes a new instance of the SortedList<TKey,TValue> class that is empty, has the specified initial capacity, and uses the specified IComparer<T>.

SortedList<TKey,TValue>()

Source:

SortedList.cs

Initializes a new instance of the SortedList<TKey,TValue> class that is empty, has the default initial capacity, and uses the default IComparer<T>.

C#

public SortedList();

Examples

The following code example creates an empty SortedList<TKey,TValue> of strings with string keys and uses the Add method to add some elements. The example demonstrates that the Add method throws an ArgumentException when attempting to add a duplicate key.

This code example is part of a larger example provided for the SortedList<TKey,TValue> class.

C#

// Create a new sorted list of strings, with string
// keys.
SortedList<string, string> openWith =
    new SortedList<string, string>();

// Add some elements to the list. There are no
// duplicate keys, but some of the values are duplicates.
openWith.Add("txt", "notepad.exe");
openWith.Add("bmp", "paint.exe");
openWith.Add("dib", "paint.exe");
openWith.Add("rtf", "wordpad.exe");

// The Add method throws an exception if the new key is
// already in the list.
try
{
    openWith.Add("txt", "winword.exe");
}
catch (ArgumentException)
{
    Console.WriteLine("An element with Key = \"txt\" already exists.");
}

Remarks

Every key in a SortedList<TKey,TValue> must be unique according to the default comparer.

This constructor uses the default value for the initial capacity of the SortedList<TKey,TValue>. To set the initial capacity, use the SortedList<TKey,TValue>(Int32) constructor. If the final size of the collection can be estimated, specifying the initial capacity eliminates the need to perform a number of resizing operations while adding elements to the SortedList<TKey,TValue>.

This constructor uses the default comparer for TKey. To specify a comparer, use the SortedList<TKey,TValue>(IComparer<TKey>) constructor. The default comparer Comparer<T>.Default checks whether the key type TKey implements System.IComparable<T> and uses that implementation, if available. If not, Comparer<T>.Default checks whether the key type TKey implements System.IComparable. If the key type TKey does not implement either interface, you can specify a System.Collections.Generic.IComparer<T> implementation in a constructor overload that accepts a comparer parameter.

This constructor is an O(1) operation.

See also

• Default
• IComparable<T>
• IComparable

SortedList<TKey,TValue>(IComparer<TKey>)

Source:

SortedList.cs

Initializes a new instance of the SortedList<TKey,TValue> class that is empty, has the default initial capacity, and uses the specified IComparer<T>.

C#

public SortedList(System.Collections.Generic.IComparer<TKey>? comparer);

Parameters

comparer

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.

Examples

The following code example creates a sorted list with a case-insensitive comparer for the current culture. The example adds four elements, some with lower-case keys and some with upper-case keys. The example then attempts to add an element with a key that differs from an existing key only by case, catches the resulting exception, and displays an error message. Finally, the example displays the elements in case-insensitive sort order.

C#

using System;
using System.Collections.Generic;

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

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

        // Try to add a fifth element with a key that is the same
        // except for case; this would be allowed with the default
        // comparer.
        try
        {
            openWith.Add("BMP", "paint.exe");
        }
        catch (ArgumentException)
        {
            Console.WriteLine("\nBMP is already in the sorted list.");
        }

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

/* This code example produces the following output:

BMP is already in the sorted list.

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

Remarks

Every key in a SortedList<TKey,TValue> must be unique according to the specified comparer.

This constructor uses the default value for the initial capacity of the SortedList<TKey,TValue>. To set the initial capacity, use the SortedList<TKey,TValue>(Int32, IComparer<TKey>) constructor. If the final size of the collection can be estimated, specifying the initial capacity eliminates the need to perform a number of resizing operations while adding elements to the SortedList<TKey,TValue>.

This constructor is an O(1) operation.

See also

• IComparer<T>
• Default
• IComparable<T>
• IComparable

SortedList<TKey,TValue>(IDictionary<TKey,TValue>)

Source:

SortedList.cs

Initializes a new instance of the SortedList<TKey,TValue> class that contains elements copied from the specified IDictionary<TKey,TValue>, has sufficient capacity to accommodate the number of elements copied, and uses the default IComparer<T>.

C#

public SortedList(System.Collections.Generic.IDictionary<TKey,TValue> dictionary);

Parameters

dictionary

IDictionary<TKey,TValue>

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

Exceptions

ArgumentNullException

dictionary is null.

ArgumentException

dictionary contains one or more duplicate keys.

Examples

The following code example shows how to use SortedList<TKey,TValue> to create a sorted copy of the information in a Dictionary<TKey,TValue>, by passing the Dictionary<TKey,TValue> to the SortedList<TKey,TValue>(IDictionary<TKey,TValue>) constructor.

C#

using System;
using System.Collections.Generic;

public class Example
{
    public static void Main()
    {
        // Create a new Dictionary of strings, with string keys.
        //
        Dictionary<string, string> openWith =
                                  new Dictionary<string, string>();

        // 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");

        // Create a SortedList of strings with string keys,
        // and initialize it with the contents of the Dictionary.
        SortedList<string, string> copy =
                  new SortedList<string, string>(openWith);

        // List the 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 = bmp, Value = paint.exe
Key = dib, Value = paint.exe
Key = rtf, Value = wordpad.exe
Key = txt, Value = notepad.exe
 */

Remarks

Every key in a SortedList<TKey,TValue> must be unique according to the default comparer; likewise, every key in the source dictionary must also be unique according to the default comparer.

The capacity of the new SortedList<TKey,TValue> is set to the number of elements in dictionary, so no resizing takes place while the list is being populated.

This constructor uses the default comparer for TKey. To specify a comparer, use the SortedList<TKey,TValue>(IDictionary<TKey,TValue>, IComparer<TKey>) constructor. The default comparer Comparer<T>.Default checks whether the key type TKey implements System.IComparable<T> and uses that implementation, if available. If not, Comparer<T>.Default checks whether the key type TKey implements System.IComparable. If the key type TKey does not implement either interface, you can specify a System.Collections.Generic.IComparer<T> implementation in a constructor overload that accepts a comparer parameter.

The keys in dictionary are copied to the new SortedList<TKey,TValue> and sorted once, which makes this constructor an O(n log n) operation.

See also

• IDictionary<TKey,TValue>
• Default
• IComparable<T>
• IComparable

SortedList<TKey,TValue>(Int32)

Source:

SortedList.cs

Initializes a new instance of the SortedList<TKey,TValue> class that is empty, has the specified initial capacity, and uses the default IComparer<T>.

C#

public SortedList(int capacity);

Parameters

capacity

Int32

The initial number of elements that the SortedList<TKey,TValue> can contain.

Exceptions

ArgumentOutOfRangeException

capacity is less than zero.

Examples

The following code example creates a sorted list with an initial capacity of 4 and populates it with 4 entries.

C#

using System;
using System.Collections.Generic;

public class Example
{
    public static void Main()
    {
        // Create a new sorted list of strings, with string keys and
        // an initial capacity of 4.
        SortedList<string, string> openWith =
                               new SortedList<string, string>(4);

        // Add 4 elements to the list.
        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 sorted list.
        Console.WriteLine();
        foreach( KeyValuePair<string, string> kvp in openWith )
        {
            Console.WriteLine("Key = {0}, Value = {1}",
               kvp.Key, kvp.Value);
        }
    }
}

/* This code example produces the following output:

Key = bmp, Value = paint.exe
Key = dib, Value = paint.exe
Key = rtf, Value = wordpad.exe
Key = txt, Value = notepad.exe
 */

Remarks

Every key in a SortedList<TKey,TValue> must be unique according to the default comparer.

The capacity of a SortedList<TKey,TValue> is the number of elements that the SortedList<TKey,TValue> can hold before resizing. As elements are added to a SortedList<TKey,TValue>, the capacity is automatically increased as required by reallocating the internal array.

If the size of the collection can be estimated, specifying the initial capacity eliminates the need to perform a number of resizing operations while adding elements to the SortedList<TKey,TValue>.

The capacity can be decreased by calling TrimExcess or by setting the Capacity property explicitly. Decreasing the capacity reallocates memory and copies all the elements in the SortedList<TKey,TValue>.

This constructor uses the default comparer for TKey. To specify a comparer, use the SortedList<TKey,TValue>(Int32, IComparer<TKey>) constructor. The default comparer Comparer<T>.Default checks whether the key type TKey implements System.IComparable<T> and uses that implementation, if available. If not, Comparer<T>.Default checks whether the key type TKey implements System.IComparable. If the key type TKey does not implement either interface, you can specify a System.Collections.Generic.IComparer<T> implementation in a constructor overload that accepts a comparer parameter.

This constructor is an O(n) operation, where n is capacity.

See also

• Capacity
• Default
• IComparable<T>
• IComparable

SortedList<TKey,TValue>(IDictionary<TKey,TValue>, IComparer<TKey>)

Source:

SortedList.cs

Initializes a new instance of the SortedList<TKey,TValue> class that contains elements copied from the specified IDictionary<TKey,TValue>, has sufficient capacity to accommodate the number of elements copied, and uses the specified IComparer<T>.

C#

public SortedList(System.Collections.Generic.IDictionary<TKey,TValue> dictionary, System.Collections.Generic.IComparer<TKey>? comparer);

Parameters

dictionary

IDictionary<TKey,TValue>

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

comparer

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.

Exceptions

ArgumentNullException

dictionary is null.

ArgumentException

dictionary contains one or more duplicate keys.

Examples

The following code example shows how to use SortedList<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 SortedList<TKey,TValue>(IDictionary<TKey,TValue>, IComparer<TKey>) constructor. In this example, the case-insensitive comparers are for the current culture.

C#

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");

        // Create a SortedList of strings with string keys and a
        // case-insensitive equality comparer for the current culture,
        // and initialize it with the contents of the Dictionary.
        SortedList<string, string> copy =
            new SortedList<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 = Bmp, Value = paint.exe
Key = DIB, Value = paint.exe
Key = rtf, Value = wordpad.exe
Key = txt, Value = notepad.exe
 */

Remarks

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

The capacity of the new SortedList<TKey,TValue> is set to the number of elements in dictionary, so no resizing takes place while the list is being populated.

The keys in dictionary are copied to the new SortedList<TKey,TValue> and sorted once, which makes this constructor an O(n log n) operation.

See also

• IDictionary<TKey,TValue>
• IComparer<T>
• Default
• IComparable<T>
• IComparable

SortedList<TKey,TValue>(Int32, IComparer<TKey>)

Source:

SortedList.cs

Initializes a new instance of the SortedList<TKey,TValue> class that is empty, has the specified initial capacity, and uses the specified IComparer<T>.

C#

public SortedList(int capacity, System.Collections.Generic.IComparer<TKey>? comparer);

Parameters

capacity

Int32

The initial number of elements that the SortedList<TKey,TValue> can contain.

comparer

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.

Exceptions

ArgumentOutOfRangeException

capacity is less than zero.

Examples

The following code example creates a sorted list with an initial capacity of 5 and a case-insensitive comparer for the current culture. The example adds four elements, some with lower-case keys and some with upper-case keys. The example then attempts to add an element with a key that differs from an existing key only by case, catches the resulting exception, and displays an error message. Finally, the example displays the elements in case-insensitive sort order.

C#

using System;
using System.Collections.Generic;

public class Example
{
    public static void Main()
    {
        // Create a new sorted list of strings, with string keys, an
        // initial capacity of 5, and a case-insensitive comparer.
        SortedList<string, string> openWith =
                      new SortedList<string, string>(5,
                          StringComparer.CurrentCultureIgnoreCase);

        // Add 4 elements to the list.
        openWith.Add("txt", "notepad.exe");
        openWith.Add("bmp", "paint.exe");
        openWith.Add("DIB", "paint.exe");
        openWith.Add("rtf", "wordpad.exe");

        // Try to add a fifth element with a key that is the same
        // except for case; this would be allowed with the default
        // comparer.
        try
        {
            openWith.Add("BMP", "paint.exe");
        }
        catch (ArgumentException)
        {
            Console.WriteLine("\nBMP is already in the sorted list.");
        }

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

/* This code example produces the following output:

BMP is already in the sorted list.

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

Remarks

Every key in a SortedList<TKey,TValue> must be unique according to the specified comparer.

The capacity of a SortedList<TKey,TValue> is the number of elements that the SortedList<TKey,TValue> can hold before resizing. As elements are added to a SortedList<TKey,TValue>, the capacity is automatically increased as required by reallocating the internal array.

If the size of the collection can be estimated, specifying the initial capacity eliminates the need to perform a number of resizing operations while adding elements to the SortedList<TKey,TValue>.

The capacity can be decreased by calling TrimExcess or by setting the Capacity property explicitly. Decreasing the capacity reallocates memory and copies all the elements in the SortedList<TKey,TValue>.

This constructor is an O(n) operation, where n is capacity.

See also

• Capacity
• IComparer<T>
• Default
• IComparable<T>
• IComparable