ValueTypeIndexerReference<TOperand, TItem> Class

Represents an element referenced by an indexer on a value type that can be used as an l-value in an expression.

          System.Activities.Expressions.ValueTypeIndexerReference<TOperand, TItem>

Namespace:  System.Activities.Expressions
Assembly:  System.Activities (in System.Activities.dll)

public sealed class ValueTypeIndexerReference<TOperand, TItem> : CodeActivity<Location<TItem>>

Type Parameters


The value type with the indexer.


The type of indexer array.

The ValueTypeIndexerReference<TOperand, TItem> type exposes the following members.

Public methodValueTypeIndexerReference<TOperand, TItem>Initializes a new instance of the ValueTypeIndexerReference<TOperand, TItem> class.

Protected propertyCacheIdGets the identifier of the cache that is unique within the scope of the workflow definition. (Inherited from Activity.)
Public propertyDisplayNameGets or sets an optional friendly name that is used for debugging, validation, exception handling, and tracking. (Inherited from Activity.)
Public propertyIdGets an identifier that is unique in the scope of the workflow definition. (Inherited from Activity.)
Protected propertyImplementationVersionGets or sets the implementation version of the activity. (Inherited from CodeActivity<TResult>.)
Public propertyIndicesGets a collection of arguments that represent the indices of the element in the indexer array.
Public propertyOperandLocationGets or sets the instance of the value type that contains the indexer.
Public propertyResultGets or sets the result argument for the Activity<TResult>. (Inherited from Activity<TResult>.)
Public propertyResultTypeWhen implemented in a derived class, gets the type of an activity OutArgument. (Inherited from ActivityWithResult.)

Public methodEquals(Object)Determines whether the specified object is equal to the current object. (Inherited from Object.)
Public methodGetHashCodeServes as the default hash function. (Inherited from Object.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodShouldSerializeDisplayNameIndicates whether the DisplayName property should be serialized. (Inherited from Activity.)
Public methodToStringReturns a String that contains the Id and DisplayName of the Activity. (Inherited from Activity.)

The following code example uses ValueTypeIndexerReference<TOperand, TItem> in an Assign activity to assign a string value to the struct element at index 1 and prints the element value to the console. The Assign activity is equivalent to the following statement when using the struct defined in the following example: myStructVariable[1] = "Hello";.


Instead of instantiating the ValueTypeIndexerReference<TOperand, TItem> l-value expression activity directly, it is strongly recommended that you call ConvertReference<TResult>, which provides a higher level of abstraction and enables you to implement your workflow more intuitively.

    // Define a struct with an indexer.
    struct StructWithIndexer
        string val;
        public string this[int index]
            get { return val; }
            set { val = value; }

    public static void ValueTypeIndexerReferenceSample()
        // Create a variable of type StructWithIndexer to store the element.
        var swivar = new Variable<StructWithIndexer>("swivar", new StructWithIndexer());

        // Create the top-level activity to be invoked later.
        Activity myActivity = new Sequence
            Variables = { swivar },
            Activities = 
                // Create an Assign activity with an element at index 1.
                new Assign<string>
                    To = new ValueTypeIndexerReference<StructWithIndexer, string>
                        OperandLocation = swivar,
                        Indices = { new InArgument<int>(1) },
                    // Assign a string literal to the element at index 1.
                    Value = "Hello",
                new WriteLine()
                    Text = ExpressionServices.Convert<string>(ctx => swivar.Get(ctx)[1]),

        // Invoke the Sequence activity.

.NET Framework

Supported in: 4.5, 4

.NET Framework Client Profile

Supported in: 4

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

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

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