IndexerReference<TOperand,TItem> Classe

Definição

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))

Parâmetros de Tipo Genérico

Herança

Object

Activity

ActivityWithResult

Activity<TResult>

CodeActivity<Location<TItem>>

IndexerReference<TOperand,TItem>

Atributos

ContentPropertyAttribute

Exemplos

O exemplo de código seguinte utiliza IndexerReference<TOperand,TItem> uma Assign atividade para atribuir um valor inteiro ao objeto no índice [1,2] e imprime o valor do item na consola. A Assign atividade é equivalente à seguinte afirmação quando se utiliza um objeto que implementa um indexador. myObj[1,2] = 4; .

// 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);
}