ValueTypeIndexerReference<TOperand,TItem> Class

Reference

Definition

Namespace:: System.Activities.Expressions

Assembly:: System.Activities.dll

Important

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

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

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

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

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

Type Parameters

TOperand

The value type with the indexer.

TItem

The type of indexer array.

Inheritance: Object

Activity

ActivityWithResult

Activity<TResult>

CodeActivity<Location<TItem>>
ValueTypeIndexerReference<TOperand,TItem>

Attributes: ContentPropertyAttribute

Examples

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";.

Note

Instead of instantiating the ValueTypeIndexerReference<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 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.  
        WorkflowInvoker.Invoke(myActivity);  
}

Constructors

ValueTypeIndexerReference<TOperand,TItem>()

Initializes a new instance of the ValueTypeIndexerReference<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.
OperandLocation	Gets or sets the instance of the value type 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)

Applies to

Dela via