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IndexerReference(TOperand, TItem) Class
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IndexerReference<TOperand, TItem> Class

.NET Framework 4.6 and 4.5

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

System.Object
  System.Activities.Activity
    System.Activities.ActivityWithResult
      System.Activities.Activity<Location<TItem>>
        System.Activities.CodeActivity<Location<TItem>>
          System.Activities.Expressions.IndexerReference<TOperand, TItem>

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

[ContentPropertyAttribute("Indices")]
public sealed class IndexerReference<TOperand, TItem> : CodeActivity<Location<TItem>>

Type Parameters

TOperand

The type with the indexer.

TItem

The type of the indexer array.

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

  NameDescription
Public methodIndexerReference<TOperand, TItem>Initializes a new instance of the IndexerReference<TOperand, TItem> class.
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  NameDescription
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 propertyOperandGets or sets the object 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.)
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  NameDescription
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.)
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The following code example uses IndexerReference<TOperand, TItem> in an Assign activity to assign an integer value to the object item at index [1,2] and prints the item value to the console. The Assign activity is equivalent to the following statement when using an object that implements an indexer. myObj[1,2] = 4; .

NoteNote

Instead of instantiating the IndexerReference<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 class with a multi-dimensional indexer.
    public class ObjectWithIndexer
    {
        private int[,] array = new int[10,10];
        public int this[int i, int j]
        {
            get { return array[i,j]; }
            set { array[i,j] = value; }
        }
    }

    public static void IndexerReferenceSample()
    {
        // Create a variable of type ObjectWithIndexer to store the object item.
        var oivar = new Variable<ObjectWithIndexer>("oivar", new ObjectWithIndexer());

        Activity myActivity = new Sequence
        {
            Variables = { oivar },
            Activities = 
            {                    
                // Create an Assign activity with a reference for the object at index [1,2].
                new Assign<int>
                {
                    To = new IndexerReference<ObjectWithIndexer, int>
                    {
                        Operand = oivar,
                        Indices =
                        {
                            new InArgument<int>(1),
                            new InArgument<int>(2)
                        }
                    },
                    // Assign an integer value to the object at index [1,2].
                    Value = 4,
                },
                // Print the new item value to the console.
                new WriteLine()
                {
                    Text = ExpressionServices.Convert<string>(ctx => oivar.Get(ctx)[1, 2].ToString()),
                }
            }
        };

        // Invoke the Sequence activity.
        WorkflowInvoker.Invoke(myActivity);
    }

.NET Framework

Supported in: 4.6, 4.5, 4

.NET Framework Client Profile

Supported in: 4

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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