Windows Dev Center

Array Class

Provides methods for creating, manipulating, searching, and sorting arrays, thereby serving as the base class for all arrays in the common language runtime.

Namespace:  System
Assembly:  mscorlib (in mscorlib.dll)

public abstract class Array : IList, 
	ICollection, IEnumerable, IStructuralComparable, IStructuralEquatable

The Array type exposes the following members.

  NameDescription
Public propertyIsFixedSizeGets a value indicating whether the Array has a fixed size.
Public propertyIsReadOnlyGets a value indicating whether the Array is read-only.
Public propertyIsSynchronizedGets a value indicating whether access to the Array is synchronized (thread safe).
Public propertyLengthGets a 32-bit integer that represents the total number of elements in all the dimensions of the Array; zero if there are no elements in the array.
Public propertyRankGets the zero-based rank (number of dimensions) of the Array.
Public propertySyncRootGets an object that can be used to synchronize access to the Array.
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  NameDescription
Public methodStatic memberAsReadOnly<T>Returns a read-only wrapper for the specified array.
Public methodStatic memberBinarySearch(Array, Object)Searches an entire one-dimensional sorted Array for a specific element, using the IComparable interface implemented by each element of the Array and by the specified object.
Public methodStatic memberBinarySearch(Array, Object, IComparer)Searches an entire one-dimensional sorted Array for a value using the specified IComparer interface.
Public methodStatic memberBinarySearch(Array, Int32, Int32, Object)Searches a range of elements in a one-dimensional sorted Array for a value, using the IComparable interface implemented by each element of the Array and by the specified value.
Public methodStatic memberBinarySearch(Array, Int32, Int32, Object, IComparer)Searches a range of elements in a one-dimensional sorted Array for a value, using the specified IComparer interface.
Public methodStatic memberBinarySearch<T>(T[], T)Searches an entire one-dimensional sorted Array for a specific element, using the IComparable<T> generic interface implemented by each element of the Array and by the specified object.
Public methodStatic memberBinarySearch<T>(T[], T, IComparer<T>)Searches an entire one-dimensional sorted Array for a value using the specified IComparer<T> generic interface.
Public methodStatic memberBinarySearch<T>(T[], Int32, Int32, T)Searches a range of elements in a one-dimensional sorted Array for a value, using the IComparable<T> generic interface implemented by each element of the Array and by the specified value.
Public methodStatic memberBinarySearch<T>(T[], Int32, Int32, T, IComparer<T>)Searches a range of elements in a one-dimensional sorted Array for a value, using the specified IComparer<T> generic interface.
Public methodStatic memberClearSets a range of elements in the Array to zero, to false, or to null, depending on the element type.
Public methodCloneCreates a shallow copy of the Array.
Public methodStatic memberConstrainedCopyCopies a range of elements from an Array starting at the specified source index and pastes them to another Array starting at the specified destination index. Guarantees that all changes are undone if the copy does not succeed completely.
Public methodStatic memberCopy(Array, Array, Int32)Copies a range of elements from an Array starting at the first element and pastes them into another Array starting at the first element. The length is specified as a 32-bit integer.
Public methodStatic memberCopy(Array, Int32, Array, Int32, Int32)Copies a range of elements from an Array starting at the specified source index and pastes them to another Array starting at the specified destination index. The length and the indexes are specified as 32-bit integers.
Public methodCopyToCopies all the elements of the current one-dimensional Array to the specified one-dimensional Array starting at the specified destination Array index. The index is specified as a 32-bit integer.
Public methodStatic memberCreateInstance(Type, Int32)Creates a one-dimensional Array of the specified Type and length, with zero-based indexing.
Public methodStatic memberCreateInstance(Type, Int32[])Creates a multidimensional Array of the specified Type and dimension lengths, with zero-based indexing. The dimension lengths are specified in an array of 32-bit integers.
Public methodStatic memberCreateInstance(Type, Int32[], Int32[])Creates a multidimensional Array of the specified Type and dimension lengths, with the specified lower bounds.
Public methodEquals(Object)Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
Public methodStatic memberExists<T>Determines whether the specified array contains elements that match the conditions defined by the specified predicate.
Protected methodFinalizeAllows an object to try to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection. (Inherited from Object.)
Public methodStatic memberFind<T>Searches for an element that matches the conditions defined by the specified predicate, and returns the first occurrence within the entire Array.
Public methodStatic memberFindAll<T>Retrieves all the elements that match the conditions defined by the specified predicate.
Public methodStatic memberFindIndex<T>(T[], Predicate<T>)Searches for an element that matches the conditions defined by the specified predicate, and returns the zero-based index of the first occurrence within the entire Array.
Public methodStatic memberFindIndex<T>(T[], Int32, Predicate<T>)Searches for an element that matches the conditions defined by the specified predicate, and returns the zero-based index of the first occurrence within the range of elements in the Array that extends from the specified index to the last element.
Public methodStatic memberFindIndex<T>(T[], Int32, Int32, Predicate<T>)Searches for an element that matches the conditions defined by the specified predicate, and returns the zero-based index of the first occurrence within the range of elements in the Array that starts at the specified index and contains the specified number of elements.
Public methodStatic memberFindLast<T>Searches for an element that matches the conditions defined by the specified predicate, and returns the last occurrence within the entire Array.
Public methodStatic memberFindLastIndex<T>(T[], Predicate<T>)Searches for an element that matches the conditions defined by the specified predicate, and returns the zero-based index of the last occurrence within the entire Array.
Public methodStatic memberFindLastIndex<T>(T[], Int32, Predicate<T>)Searches for an element that matches the conditions defined by the specified predicate, and returns the zero-based index of the last occurrence within the range of elements in the Array that extends from the first element to the specified index.
Public methodStatic memberFindLastIndex<T>(T[], Int32, Int32, Predicate<T>)Searches for an element that matches the conditions defined by the specified predicate, and returns the zero-based index of the last occurrence within the range of elements in the Array that contains the specified number of elements and ends at the specified index.
Public methodStatic memberForEach<T>Performs the specified action on each element of the specified array.
Public methodGetEnumeratorReturns an IEnumerator for the Array.
Public methodGetHashCodeServes as a hash function for a particular type. (Inherited from Object.)
Public methodGetLengthGets a 32-bit integer that represents the number of elements in the specified dimension of the Array.
Public methodGetLowerBoundGets the lower bound of the specified dimension in the Array.
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodGetUpperBoundGets the upper bound of the specified dimension in the Array.
Public methodGetValue(Int32)Gets the value at the specified position in the one-dimensional Array. The index is specified as a 32-bit integer.
Public methodGetValue(Int32[])Gets the value at the specified position in the multidimensional Array. The indexes are specified as an array of 32-bit integers.
Public methodStatic memberIndexOf(Array, Object)Searches for the specified object and returns the index of the first occurrence within the entire one-dimensional Array.
Public methodStatic memberIndexOf(Array, Object, Int32)Searches for the specified object and returns the index of the first occurrence within the range of elements in the one-dimensional Array that extends from the specified index to the last element.
Public methodStatic memberIndexOf(Array, Object, Int32, Int32)Searches for the specified object and returns the index of the first occurrence within the range of elements in the one-dimensional Array that starts at the specified index and contains the specified number of elements.
Public methodStatic memberIndexOf<T>(T[], T)Searches for the specified object and returns the index of the first occurrence within the entire Array.
Public methodStatic memberIndexOf<T>(T[], T, Int32)Searches for the specified object and returns the index of the first occurrence within the range of elements in the Array that extends from the specified index to the last element.
Public methodStatic memberIndexOf<T>(T[], T, Int32, Int32)Searches for the specified object and returns the index of the first occurrence within the range of elements in the Array that starts at the specified index and contains the specified number of elements.
Public methodInitializeInitializes every element of the value-type Array by calling the default constructor of the value type.
Public methodStatic memberLastIndexOf(Array, Object)Searches for the specified object and returns the index of the last occurrence within the entire one-dimensional Array.
Public methodStatic memberLastIndexOf(Array, Object, Int32)Searches for the specified object and returns the index of the last occurrence within the range of elements in the one-dimensional Array that extends from the first element to the specified index.
Public methodStatic memberLastIndexOf(Array, Object, Int32, Int32)Searches for the specified object and returns the index of the last occurrence within the range of elements in the one-dimensional Array that contains the specified number of elements and ends at the specified index.
Public methodStatic memberLastIndexOf<T>(T[], T)Searches for the specified object and returns the index of the last occurrence within the entire Array.
Public methodStatic memberLastIndexOf<T>(T[], T, Int32)Searches for the specified object and returns the index of the last occurrence within the range of elements in the Array that extends from the first element to the specified index.
Public methodStatic memberLastIndexOf<T>(T[], T, Int32, Int32)Searches for the specified object and returns the index of the last occurrence within the range of elements in the Array that contains the specified number of elements and ends at the specified index.
Protected methodMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public methodStatic memberResize<T>Changes the number of elements of an array to the specified new size.
Public methodStatic memberReverse(Array)Reverses the sequence of the elements in the entire one-dimensional Array.
Public methodStatic memberReverse(Array, Int32, Int32)Reverses the sequence of the elements in a range of elements in the one-dimensional Array.
Public methodSetValue(Object, Int32)Sets a value to the element at the specified position in the one-dimensional Array. The index is specified as a 32-bit integer.
Public methodSetValue(Object, Int32[])Sets a value to the element at the specified position in the multidimensional Array. The indexes are specified as an array of 32-bit integers.
Public methodStatic memberSort(Array)Sorts the elements in an entire one-dimensional Array using the IComparable implementation of each element of the Array.
Public methodStatic memberSort(Array, IComparer)Sorts the elements in a one-dimensional Array using the specified IComparer.
Public methodStatic memberSort(Array, Array, IComparer)Sorts a pair of one-dimensional Array objects (one contains the keys and the other contains the corresponding items) based on the keys in the first Array using the specified IComparer.
Public methodStatic memberSort(Array, Int32, Int32)Sorts the elements in a range of elements in a one-dimensional Array using the IComparable implementation of each element of the Array.
Public methodStatic memberSort(Array, Int32, Int32, IComparer)Sorts the elements in a range of elements in a one-dimensional Array using the specified IComparer.
Public methodStatic memberSort(Array, Array, Int32, Int32, IComparer)Sorts a range of elements in a pair of one-dimensional Array objects (one contains the keys and the other contains the corresponding items) based on the keys in the first Array using the specified IComparer.
Public methodStatic memberSort<T>(T[])Sorts the elements in an entire Array using the IComparable<T> generic interface implementation of each element of the Array.
Public methodStatic memberSort<T>(T[], IComparer<T>)Sorts the elements in an Array using the specified IComparer<T> generic interface.
Public methodStatic memberSort<T>(T[], Comparison<T>)Sorts the elements in an Array using the specified Comparison<T>.
Public methodStatic memberSort<T>(T[], Int32, Int32)Sorts the elements in a range of elements in an Array using the IComparable<T> generic interface implementation of each element of the Array.
Public methodStatic memberSort<T>(T[], Int32, Int32, IComparer<T>)Sorts the elements in a range of elements in an Array using the specified IComparer<T> generic interface.
Public methodStatic memberSort<TKey, TValue>(TKey[], TValue[])Sorts a pair of Array objects (one contains the keys and the other contains the corresponding items) based on the keys in the first Array using the IComparable<T> generic interface implementation of each key.
Public methodStatic memberSort<TKey, TValue>(TKey[], TValue[], IComparer<TKey>)Sorts a pair of Array objects (one contains the keys and the other contains the corresponding items) based on the keys in the first Array using the specified IComparer<T> generic interface.
Public methodStatic memberSort<TKey, TValue>(TKey[], TValue[], Int32, Int32)Sorts a range of elements in a pair of Array objects (one contains the keys and the other contains the corresponding items) based on the keys in the first Array using the IComparable<T> generic interface implementation of each key.
Public methodStatic memberSort<TKey, TValue>(TKey[], TValue[], Int32, Int32, IComparer<TKey>)Sorts a range of elements in a pair of Array objects (one contains the keys and the other contains the corresponding items) based on the keys in the first Array using the specified IComparer<T> generic interface.
Public methodToStringReturns a string that represents the current object. (Inherited from Object.)
Public methodStatic memberTrueForAll<T>Determines whether every element in the array matches the conditions defined by the specified predicate.
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  NameDescription
Public Extension MethodAsQueryableConverts an IEnumerable to an IQueryable. (Defined by Queryable.)
Public Extension MethodCast<TResult>Converts the elements of an IEnumerable to the specified type. (Defined by Enumerable.)
Public Extension MethodOfType<TResult>Filters the elements of an IEnumerable based on a specified type. (Defined by Enumerable.)
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  NameDescription
Explicit interface implemetationPrivate propertyICollection.CountGets the number of elements contained in the Array.
Explicit interface implemetationPrivate methodIList.AddImplements IList.Add. Throws a NotSupportedException in all cases.
Explicit interface implemetationPrivate methodIList.ClearSets all elements in the Array to zero, to false, or to null, depending on the element type.
Explicit interface implemetationPrivate methodIList.ContainsDetermines whether an element is in the Array.
Explicit interface implemetationPrivate methodIList.IndexOfSearches for the specified object and returns the index of the first occurrence within the current one-dimensional instance.
Explicit interface implemetationPrivate methodIList.InsertImplements IList.Insert. Throws a NotSupportedException in all cases.
Explicit interface implemetationPrivate propertyIList.ItemGets or sets the element at the specified index.
Explicit interface implemetationPrivate methodIList.RemoveImplements IList.Remove. Throws a NotSupportedException in all cases.
Explicit interface implemetationPrivate methodIList.RemoveAtImplements IList.RemoveAt. Throws a NotSupportedException in all cases.
Explicit interface implemetationPrivate methodIStructuralComparable.CompareToDetermines whether the current collection object precedes, occurs in the same position as, or follows another object in the sort order.
Explicit interface implemetationPrivate methodIStructuralEquatable.EqualsDetermines whether an object is equal to the current instance.
Explicit interface implemetationPrivate methodIStructuralEquatable.GetHashCodeReturns a hash code for the current instance.
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The Array class is the base class for language implementations that support arrays. However, only the system and compilers can derive explicitly from the Array class. Users should employ the array constructs provided by the language.

An element is a value in an Array. The length of an Array is the total number of elements it can contain. The rank of an Array is the number of dimensions in the Array. The lower bound of a dimension of an Array is the starting index of that dimension of the Array; a multidimensional Array can have different bounds for each dimension.

Type objects provide information about array type declarations. Array objects with the same array type share the same Type object.

Type.IsArray and Type.GetElementType might not return the expected results with Array because if an array is cast to the type Array, the result is an object, not an array. That is, typeof(System.Array).IsArray returns false, and typeof(System.Array).GetElementType returns null.

Unlike most classes, Array provides the CreateInstance method, instead of public constructors, to allow for late bound access.

The Array.Copy method copies elements not only between arrays of the same type but also between standard arrays of different types; it handles type casting automatically.

The Array is not guaranteed to be sorted. You must sort the Array prior to performing operations (such as BinarySearch that require the Array to be sorted.

The following code example shows how Array.Copy copies elements between an array of type integer and an array of type Object.

NoteNote:

For information on how to compile and run this example code, see Building examples that have static TextBlock controls for Windows Phone 8.


using System;
public class Example
{
    public static void Demo(System.Windows.Controls.TextBlock outputBlock)
    {

        // Creates and initializes a new integer array and a new Object array.
        int[] myIntArray = new int[5] { 1, 2, 3, 4, 5 };
        Object[] myObjArray = new Object[5] { 26, 27, 28, 29, 30 };

        // Prints the initial values of both arrays.
        outputBlock.Text += String.Format("Initially:") + "\n";
        outputBlock.Text += "integer array:";
        PrintValues(outputBlock, myIntArray);
        outputBlock.Text += "Object array: ";
        PrintValues(outputBlock, myObjArray);

        // Copies the first two elements from the integer array to the Object array.
        Array.Copy(myIntArray, myObjArray, 2);

        // Prints the values of the modified arrays.
        outputBlock.Text += String.Format("\nAfter copying the first two elements of the integer array to the Object array,") + "\n";
        outputBlock.Text += "integer array:";
        PrintValues(outputBlock, myIntArray);
        outputBlock.Text += "Object array: ";
        PrintValues(outputBlock, myObjArray);

        // Copies the last two elements from the Object array to the integer array.
        Array.Copy(myObjArray, myObjArray.GetUpperBound(0) - 1, myIntArray, myIntArray.GetUpperBound(0) - 1, 2);

        // Prints the values of the modified arrays.
        outputBlock.Text += String.Format("\nAfter copying the last two elements of the Object array to the integer array,") + "\n";
        outputBlock.Text += "integer array:";
        PrintValues(outputBlock, myIntArray);
        outputBlock.Text += "Object array: ";
        PrintValues(outputBlock, myObjArray);
    }


    public static void PrintValues(System.Windows.Controls.TextBlock outputBlock, Object[] myArr)
    {
        foreach (Object i in myArr)
        {
            outputBlock.Text += String.Format("   {0}", i);
        }
        outputBlock.Text += "\n";
    }

    public static void PrintValues(System.Windows.Controls.TextBlock outputBlock, int[] myArr)
    {
        foreach (int i in myArr)
        {
            outputBlock.Text += String.Format("   {0}", i);
        }
        outputBlock.Text += "\n";
    }
    /* 
    This code produces the following output.

    Initially,
    integer array:  1       2       3       4       5
    Object array:   26      27      28      29      30

    After copying the first two elements of the integer array to the Object array,
    integer array:  1       2       3       4       5
    Object array:   1       2       28      29      30

    After copying the last two elements of the Object array to the integer array,
    integer array:  1       2       3       29      30
    Object array:   1       2       28      29      30
    */
}



The following code example creates and initializes an Array and displays its properties and its elements.


public class Example2
{

    public static void Demo(System.Windows.Controls.TextBlock outputBlock)
    {
        // Creates and initializes a new three-dimensional Array of type Int32.
        Array myArr = Array.CreateInstance(typeof(Int32), 2, 3, 4);
        for (int i = myArr.GetLowerBound(0); i <= myArr.GetUpperBound(0); i++)
            for (int j = myArr.GetLowerBound(1); j <= myArr.GetUpperBound(1); j++)
                for (int k = myArr.GetLowerBound(2); k <= myArr.GetUpperBound(2); k++)
                {
                    myArr.SetValue((i * 100) + (j * 10) + k, i, j, k);
                }

        // Displays the properties of the Array.
        outputBlock.Text += String.Format("The Array has {0} dimension(s) and a total of {1} elements.", myArr.Rank, myArr.Length) + "\n";
        outputBlock.Text += "  Length  Lower  Upper" + "\n";
        for (int i = 0; i < myArr.Rank; i++)
        {
            outputBlock.Text += String.Format("{0}:  {1}", i, myArr.GetLength(i));
            outputBlock.Text += String.Format("  {0}  {1}", myArr.GetLowerBound(i), myArr.GetUpperBound(i)) + "\n";
        }

        // Displays the contents of the Array.
        outputBlock.Text += "The Array contains the following values:" + "\n";
        PrintValues(outputBlock, myArr);
    }


    public static void PrintValues(System.Windows.Controls.TextBlock outputBlock, Array myArr)
    {
        System.Collections.IEnumerator myEnumerator = myArr.GetEnumerator();
        int i = 0;
        int cols = myArr.GetLength(myArr.Rank - 1);
        while (myEnumerator.MoveNext())
        {
            if (i < cols)
            {
                i++;
            }
            else
            {
                outputBlock.Text += "\n";
                i = 1;
            }
            outputBlock.Text += String.Format("   {0}", myEnumerator.Current);
        }
        outputBlock.Text += "\n";
    }
}


Windows Phone OS

Supported in: 8.1, 8.0, 7.1, 7.0

Windows Phone

Public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

This implementation does not provide a synchronized (thread safe) wrapper for an Array; however, .NET Framework classes based on Array provide their own synchronized version of the collection using the SyncRoot property.

Enumerating through a collection is intrinsically not a thread-safe procedure. Even when a collection is synchronized, other threads can still modify the collection, which causes the enumerator to throw an exception. To guarantee thread safety during enumeration, you can either lock the collection during the entire enumeration or catch the exceptions resulting from changes made by other threads.

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