InvokeOperation Class

Artigo
01/27/2012

[WCF RIA Services Version 1 Service Pack 2 is compatible with either .NET framework 4 or .NET Framework 4.5, and with either Silverlight 4 or Silverlight 5.]

Represents an asynchronous invoke operation.

Inheritance Hierarchy

System.Object
  System.ServiceModel.DomainServices.Client.OperationBase
    System.ServiceModel.DomainServices.Client.InvokeOperation
      System.ServiceModel.DomainServices.Client.InvokeOperation<TValue>

Namespace: System.ServiceModel.DomainServices.Client
Assembly: System.ServiceModel.DomainServices.Client (in System.ServiceModel.DomainServices.Client.dll)

Syntax

'Declaration
Public Class InvokeOperation _
    Inherits OperationBase

'Usage
Dim instance As InvokeOperation

public class InvokeOperation : OperationBase

public ref class InvokeOperation : public OperationBase

type InvokeOperation =  
    class
        inherit OperationBase
    end

public class InvokeOperation extends OperationBase

The InvokeOperation type exposes the following members.

Properties

	Name	Description
	CanCancel	Gets a value that indicates whether this OperationBase is currently in a state that enables it to be canceled. (Inherited from OperationBase.)
	Error	Gets the operation error if the operation failed. (Inherited from OperationBase.)
	HasError	Gets a value that indicates whether the operation failed. (Inherited from OperationBase.)
	IsCanceled	Gets a value that indicates whether this operation has been canceled. (Inherited from OperationBase.)
	IsComplete	Gets a value that indicates whether this operation has completed. (Inherited from OperationBase.)
	IsErrorHandled	Gets or sets a value that indicates whether the operation error has been handled. (Inherited from OperationBase.)
	OperationName	Gets the name of the operation.
	Parameters	Gets the collection of parameters to the operation.
	Result	Gets the DomainClientResult for this operation.
	SupportsCancellation	Gets a value indicating whether this operation supports cancellation. (Overrides OperationBase.SupportsCancellation.)
	UserState	Gets the optional user state for this operation. (Inherited from OperationBase.)
	ValidationErrors	Gets the validation errors for this operation.
	Value	Gets the return value for the invoke operation.

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Methods

	Name	Description
	Cancel	Cancels the operation. (Inherited from OperationBase.)
	CancelCore	Invokes the cancel callback. (Overrides OperationBase.CancelCore().)
	Complete(Exception)	Completes a failed operation with the specified error. (Inherited from OperationBase.)
	Complete(Object)	Completes a successful operation with the specified result. (Inherited from OperationBase.)
	Equals	(Inherited from Object.)
	Finalize	(Inherited from Object.)
	GetHashCode	(Inherited from Object.)
	GetType	(Inherited from Object.)
	InvokeCompleteAction	Invokes the completion callback. (Overrides OperationBase.InvokeCompleteAction().)
	MarkErrorAsHandled	Specifies that an error encountered in an operation is handled. (Inherited from OperationBase.)
	MemberwiseClone	(Inherited from Object.)
	OnPropertyChanged	Called when the value of a property changes. (Inherited from OperationBase.)
	RaisePropertyChanged	Raises the System#ComponentModel#INotifyPropertyChanged#PropertyChanged() event. (Inherited from OperationBase.)
	ToString	(Inherited from Object.)

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Events

	Name	Description
	Completed	Occurs when the operation completes. (Inherited from OperationBase.)

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Explicit Interface Implementations

	Name	Description
	INotifyPropertyChanged.PropertyChanged	Occurs when a property value changes. (Inherited from OperationBase.)

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Examples

Partial Public Class MainPage
    Inherits UserControl

    ' Create the DomainContext for the DomainService
    Private _customerContext As CustomerDomainContext = New CustomerDomainContext()

    Friend invokeOp As InvokeOperation = New InvokeOperation()

    ' In this example, the value of the invoke operations is supposed to be a string
    Friend result As Integer


    Dim opEx As DomainOperationException = New DomainOperationException()

    Public Function MainPage()
        InitializeComponent()

        'Set invokeOp equal to _customerContext.CountCustomers
        invokeOp = _customerContext.CountCustomers(OnInvokeCompleted, Nothing)

        Dim query As EntityQuery(Of Customer) =
            From c In _customerContext.GetCustomersQuery
            Where c.Phone.StartsWith("583")
            Order By c.LastName
            Select c

        Dim loadOp As LoadOperation(Of Customer) = this._customerContext.Load(query, LoadBehavior.MergeIntoCurrent, False)

        opEx = New DomainOperationException("Validation Error",
                                            OperationErrorStatus.ValidationFailed,
                                            326)
        If loadOp.ValidationErrors <> Nothing Then
            Throw opEx
        End If

        Dim qr As QueryResult(Of Customer) = New QueryResult(Of Customer)()

        CustomerGrid.ItemsSource = qr.IncludedResults

    End Function

    'Create a method for handling the InvokeOperations onCompleted.
    Private Function OnInvokeCompleted(ByVal invOp As InvokeOperation)
        If invOp.HasError = True Then
            If invOp.ValidationErrors <> Nothing Then
                Throw opEx
            Else
                MessageBox.Show(String.Format("An Error Occured" + vbCrLf + _
                                              "Error Message: {0}" + vbCrLf + _
                                              "InnerException: {1}", invOp.Message, invOp.InnerException.Message))
                invOp.MarkErrorAsHandled()
            End If

        Else
            result = invokeOp.Value
        End If
    End Function

End Class

public partial class MainPage : UserControl
{
    // Create the DomainContext for the DomainService
    private CustomerDomainContext _customerContext = new CustomerDomainContext();

    InvokeOperation invokeOp = new InvokeOperation();
    string result;

    DomainOperationException opEx = new DomainOperationException();

    public MainPage()
    {
        InitializeComponent();

        // Set invokeOp equal to _customerContext.CountCustomers
        invokeOp = _customerContext.CountCustomers(OnInvokeCompleted, null);

        EntityQuery<Customer> query =
            from c in _customerContext.GetCustomersQuery()
            where c.Phone.StartsWith("583")
            orderby c.LastName
            select c;
        LoadOperation<Customer> loadOp = this._customerContext.Load(query, LoadBehavior.MergeIntoCurrent, false);

        opEx = new DomainOperationException(
            "Validation Error",
            OperationErrorStatus.ValidationFailed,
            0x000024FA);

        if (loadOp.ValidationErrors != null)
        {
            throw opEx;
        }

        QueryResult<Customer> qr = new QueryResult<Customer>();

        CustomerGrid.ItemsSource = qr.IncludedResults;
    }

    // Create a method for Handling the InvokeOperation Completed.
    private void OnInvokeCompleted(InvokeOperation invOp)
    {
        if (invOp.HasError)
        {
            if (invOp.ValidationErrors != null)
            {
                throw opEx;
            }
            else
            {
                MessageBox.Show(string.Format("An Error Occured/nError Message: {0}/nInner Exception Message: {1}",
                                              invOp.Error.Message,
                                              invOp.Error.InnerException.Message));
                invOp.MarkErrorAsHandled();
            }
        }
        else
        {
            // Convert the value of invokeOp which is an integer to a string for output
            // in the result field.
            result = invokeOp.Value.ToString();
            MessageBox(string.Format("InvokeOperation '{0}' has completed", invokeOp.OperationName);

        }
    }
}

Thread Safety

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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