IndexerReference<TOperand,TItem> Class

Definition

Namespace:

System.Activities.Expressions

Assembly:

System.Activities.dll

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

generic <typename TOperand, typename TItem>
public ref class IndexerReference sealed : System::Activities::CodeActivity<System::Activities::Location<TItem> ^>

[System.Windows.Markup.ContentProperty("Indices")]
public sealed class IndexerReference<TOperand,TItem> : System.Activities.CodeActivity<System.Activities.Location<TItem>>

[<System.Windows.Markup.ContentProperty("Indices")>]
type IndexerReference<'Operand, 'Item> = class
    inherit CodeActivity<Location<'Item>>

Public NotInheritable Class IndexerReference(Of TOperand, TItem)
Inherits CodeActivity(Of Location(Of TItem))

Type Parameters

TOperand

The type with the indexer.

TItem

The type of the indexer array.

Inheritance

Object

Activity

ActivityWithResult

Activity<TResult>

CodeActivity<Location<TItem>>

IndexerReference<TOperand,TItem>

Attributes

ContentPropertyAttribute

Examples

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; .

Note

Instead of instantiating the IndexerReference<TOperand,TItem> l-value expression activity directly, it is strongly recommended that you call ConvertReference, 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);  
}  

Constructors

IndexerReference<TOperand,TItem>()

Initializes a new instance of the IndexerReference<TOperand,TItem> class.

Properties

CacheId	Gets the identifier of the cache that is unique within the scope of the workflow definition. (Inherited from Activity)
Constraints	Gets a collection of Constraint activities that can be configured to provide validation for the Activity. (Inherited from Activity)
DisplayName	Gets or sets an optional friendly name that is used for debugging, validation, exception handling, and tracking. (Inherited from Activity)
Id	Gets an identifier that is unique in the scope of the workflow definition. (Inherited from Activity)
Implementation	Not supported. (Inherited from CodeActivity<TResult>)
ImplementationVersion	Gets or sets the implementation version of the activity. (Inherited from CodeActivity<TResult>)
Indices	Gets a collection of arguments that represent the indices of the element in the indexer array.
Operand	Gets or sets the object that contains the indexer.
Result	Gets or sets the result argument for the Activity<TResult>. (Inherited from Activity<TResult>)
ResultType	When implemented in a derived class, gets the type of an activity OutArgument. (Inherited from ActivityWithResult)

Methods

CacheMetadata(ActivityMetadata)	Not implemented. Use CacheMetadata(CodeActivityMetadata) instead. (Inherited from CodeActivity<TResult>)
CacheMetadata(CodeActivityMetadata)	Creates and validates a description of the activity's arguments, variables, child activities, and activity delegates. (Inherited from CodeActivity<TResult>)
Equals(Object)	Determines whether the specified object is equal to the current object. (Inherited from Object)
Execute(CodeActivityContext)	When implemented in a derived class, performs the execution of the activity. (Inherited from CodeActivity<TResult>)
GetHashCode()	Serves as the default hash function. (Inherited from Object)
GetType()	Gets the Type of the current instance. (Inherited from Object)
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
OnCreateDynamicUpdateMap(UpdateMapMetadata, Activity)	Raises an event when creating a map for the dynamic update. (Inherited from CodeActivity<TResult>)
ShouldSerializeDisplayName()	Indicates whether the DisplayName property should be serialized. (Inherited from Activity)
ToString()	Returns a String that contains the Id and DisplayName of the Activity. (Inherited from Activity)