Array.SyncRoot Property

Reference

Definition

Namespace:: System

Assemblies:: netstandard.dll, System.Runtime.dll

Assembly:: System.Runtime.dll

Assembly:: mscorlib.dll

Assembly:: netstandard.dll

Source:: Array.cs

Source:: Array.cs

Source:: Array.cs

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

Gets an object that can be used to synchronize access to the Array.

public:
 property System::Object ^ SyncRoot { System::Object ^ get(); };

public:
 virtual property System::Object ^ SyncRoot { System::Object ^ get(); };

public object SyncRoot { get; }

public virtual object SyncRoot { get; }

member this.SyncRoot : obj

Public ReadOnly Property SyncRoot As Object

Public Overridable ReadOnly Property SyncRoot As Object

Property Value

Object

An object that can be used to synchronize access to the Array.

Implements

SyncRoot

Examples

The following code example shows how to lock an array during the entire enumeration by using the SyncRoot property.

Array^ myArray = gcnew array<Int32> { 1, 2, 4 };
try
{
    Monitor::Enter(myArray->SyncRoot); 
        
    for each (Int32 item in myArray)
        Console::WriteLine(item);
}
finally
{
    Monitor::Exit(myArray->SyncRoot);
}

Array myArray = new int[] { 1, 2, 4 };
lock(myArray.SyncRoot)
{
    foreach (Object item in myArray)
        Console.WriteLine(item);
}

let myArray = [| 1; 2; 4|]
lock myArray.SyncRoot (fun () ->
    for item in myArray do
        printfn $"{item}" )

Dim myArray As Array = New Integer() { 1, 2, 4 }
SyncLock(myArray.SyncRoot) 
    For Each item As Object In myArray
        Console.WriteLine(item)
    Next
End SyncLock

Remarks

This property implements the System.Collections.ICollection interface.

.NET classes based on Array provide their own synchronized version of the collection using the SyncRoot property.

Classes that use arrays can also implement their own synchronization using the SyncRoot property. The synchronizing code must perform operations on the SyncRoot of the collection, not directly on the collection. This ensures proper operation of collections that are derived from other objects. Specifically, it maintains proper synchronization with other threads that might be simultaneously modifying the collection. Note that some implementations of SyncRoot might return the Array itself.

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.

Retrieving the value of this property is an O(1) operation.

Applies to

Product	Versions
.NET	Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9
.NET Framework	1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
.NET Standard	2.0, 2.1

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