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CollectionDataContractAttribute Class

When applied to a collection type, enables custom specification of the collection item elements. This attribute can be applied only to types that are recognized by the DataContractSerializer as valid, serializable collections.

Namespace:  System.Runtime.Serialization
Assembly:  System.Runtime.Serialization (in System.Runtime.Serialization.dll)

[AttributeUsageAttribute(AttributeTargets.Class|AttributeTargets.Struct, Inherited = false, 
	AllowMultiple = false)]
public sealed class CollectionDataContractAttribute : Attribute

The CollectionDataContractAttribute is intended to ease interoperability when working with data from non-WCF providers and to control the exact shape of serialized instances. To this end, the ItemName property enables you to control the names of the repeating items inside a collection. This is especially useful when the provider does not use the XML element type name as the array item name, for example, if a provider uses "String" as an element type name instead of the XSD type name "string".

The CollectionDataContractAttribute is also intended to be used with dictionary types to handle keyed collections. Dictionary types are classes that implement either the IDictionary or the IDictionary<TKey, TValue> interface, for example, the Dictionary<TKey, TValue>. Use the KeyName and ValueName properties to set custom names when using the Dictionary<TKey, TValue> class.

For more information about using the DataContractSerializer, see Data Contracts Overview.

The following example applies the CollectionDataContractAttribute to a class that inherits from the List<T> class. The code sets the Name and ItemName properties to custom values.

[CollectionDataContract(Name = "Custom{0}List", ItemName = "CustomItem")]
public class CustomList<T> : List<T>
    public CustomList()
        : base()

    public CustomList(T[] items)
        : base()
        foreach (T item in items)

When the Service Model Metadata Utility Tool (Svcutil.exe) is used to generate code for the client, the code resembles the following example. Notice that the name of the class is changed, as well as the ItemName. When using generics, the type parameter name is used to create the resulting type name.

// This is the generated code. Note that the class is renamed to "CustomBookList", 
// and the ItemName is set to "CustomItem".
[System.CodeDom.Compiler.GeneratedCodeAttribute("System.Runtime.Serialization", "")]
[System.Runtime.Serialization.CollectionDataContractAttribute(ItemName = "CustomItem")]
public class CustomBookList : System.Collections.Generic.List<Microsoft.Security.Samples.Book>


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

Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0