XmlMessageFormatter.TargetTypes 属性
定义
重要
一些信息与预发行产品相关，相应产品在发行之前可能会进行重大修改。 对于此处提供的信息，Microsoft 不作任何明示或暗示的担保。
指定一组可能的类型，这些类型将由格式化程序从提供的消息反序列化。
public:
property cli::array <Type ^> ^ TargetTypes { cli::array <Type ^> ^ get(); void set(cli::array <Type ^> ^ value); };[System.ComponentModel.Browsable(false)]
[System.Messaging.MessagingDescription("XmlMsgTargetTypes")]
public Type[] TargetTypes { get; set; }[<System.ComponentModel.Browsable(false)>]
[<System.Messaging.MessagingDescription("XmlMsgTargetTypes")>]
member this.TargetTypes : Type[] with get, setPublic Property TargetTypes As Type()属性值
Type[]
一个类型的 Type 数组，指定要在读取消息时从消息正文反序列化的对象类型。
- 属性
例外
属性 TargetTypes 为 null.
示例
下面的代码示例发送和接收包含队列的订单的消息。
#using <system.dll>
#using <system.messaging.dll>
#using <system.drawing.dll>
using namespace System;
using namespace System::Messaging;
using namespace System::Drawing;
using namespace System::IO;
ref class Order
{
public:
int orderId;
DateTime orderTime;
};
ref class MyNewQueue
{
public:
static void CreateQueue( String^ queuePath )
{
try
{
if ( !MessageQueue::Exists( queuePath ) )
{
MessageQueue::Create( queuePath );
}
else
{
Console::WriteLine( "{0} already exists.", queuePath );
}
}
catch ( MessageQueueException^ e )
{
Console::WriteLine( e->Message );
}
}
void SendMessage()
{
try
{
// Create a new order and set values.
Order^ sentOrder = gcnew Order;
sentOrder->orderId = 3;
sentOrder->orderTime = DateTime::Now;
// Connect to a queue on the local computer.
MessageQueue^ myQueue = gcnew MessageQueue( ".\\myQueue" );
// Create the new order.
Message^ myMessage = gcnew Message( sentOrder );
// Send the order to the queue.
myQueue->Send( myMessage );
}
catch ( ArgumentException^ e )
{
Console::WriteLine( e->Message );
}
return;
}
void ReceiveMessage()
{
// Connect to the a queue on the local computer.
MessageQueue^ myQueue = gcnew MessageQueue( ".\\myQueue" );
// Set the formatter to indicate body contains an Order.
array<Type^>^p = gcnew array<Type^>(1);
p[ 0 ] = Order::typeid;
myQueue->Formatter = gcnew XmlMessageFormatter( p );
try
{
// Receive and format the message.
Message^ myMessage = myQueue->Receive();
Order^ myOrder = dynamic_cast<Order^>(myMessage->Body);
// Display message information.
Console::WriteLine( "Order ID: {0}", myOrder->orderId );
Console::WriteLine( "Sent: {0}", myOrder->orderTime );
}
catch ( MessageQueueException^ )
{
// Handle Message Queuing exceptions.
}
// Handle invalid serialization format.
catch ( InvalidOperationException^ e )
{
Console::WriteLine( e->Message );
}
// Catch other exceptions as necessary.
return;
}
};
int main()
{
// Create a new instance of the class.
MyNewQueue^ myNewQueue = gcnew MyNewQueue;
// Create a queue on the local computer.
MyNewQueue::CreateQueue( ".\\myQueue" );
// Send a message to a queue.
myNewQueue->SendMessage();
// Receive a message from a queue.
myNewQueue->ReceiveMessage();
return 0;
}
using System;
using System.Messaging;
using System.Drawing;
using System.IO;
namespace MyProject
{
// The following example
// sends to a queue and receives from a queue.
public class Order
{
public int orderId;
public DateTime orderTime;
};
/// <summary>
/// Provides a container class for the example.
/// </summary>
public class MyNewQueue
{
//**************************************************
// Provides an entry point into the application.
//
// This example sends and receives a message from
// a queue.
//**************************************************
public static void Main()
{
// Create a new instance of the class.
MyNewQueue myNewQueue = new MyNewQueue();
// Create a queue on the local computer.
CreateQueue(".\\myQueue");
// Send a message to a queue.
myNewQueue.SendMessage();
// Receive a message from a queue.
myNewQueue.ReceiveMessage();
return;
}
//**************************************************
// Creates a new queue.
//**************************************************
public static void CreateQueue(string queuePath)
{
try
{
if(!MessageQueue.Exists(queuePath))
{
MessageQueue.Create(queuePath);
}
else
{
Console.WriteLine(queuePath + " already exists.");
}
}
catch (MessageQueueException e)
{
Console.WriteLine(e.Message);
}
}
//**************************************************
// Sends an Order to a queue.
//**************************************************
public void SendMessage()
{
try
{
// Create a new order and set values.
Order sentOrder = new Order();
sentOrder.orderId = 3;
sentOrder.orderTime = DateTime.Now;
// Connect to a queue on the local computer.
MessageQueue myQueue = new MessageQueue(".\\myQueue");
// Create the new order.
Message myMessage = new Message(sentOrder);
// Send the order to the queue.
myQueue.Send(myMessage);
}
catch(ArgumentException e)
{
Console.WriteLine(e.Message);
}
return;
}
//**************************************************
// Receives a message containing an order.
//**************************************************
public void ReceiveMessage()
{
// Connect to the a queue on the local computer.
MessageQueue myQueue = new MessageQueue(".\\myQueue");
// Set the formatter to indicate body contains an Order.
myQueue.Formatter = new XmlMessageFormatter(new Type[]
{typeof(MyProject.Order)});
try
{
// Receive and format the message.
Message myMessage = myQueue.Receive();
Order myOrder = (Order)myMessage.Body;
// Display message information.
Console.WriteLine("Order ID: " +
myOrder.orderId.ToString());
Console.WriteLine("Sent: " +
myOrder.orderTime.ToString());
}
catch (MessageQueueException)
{
// Handle Message Queuing exceptions.
}
// Handle invalid serialization format.
catch (InvalidOperationException e)
{
Console.WriteLine(e.Message);
}
// Catch other exceptions as necessary.
return;
}
}
}
Imports System.Messaging
Imports System.Drawing
Imports System.IO
' The following example
' sends to a queue and receives from a queue.
Public Class Order
Public orderId As Integer
Public orderTime As DateTime
End Class
' Provides a container class for the example.
Public Class MyNewQueue
' Provides an entry point into the application.
'
' This example sends and receives a message from
' a queue.
Public Shared Sub Main()
' Create a new instance of the class.
Dim myNewQueue As New MyNewQueue()
' Create a queue on the local computer.
CreateQueue(".\myQueue")
' Send a message to a queue.
myNewQueue.SendMessage()
' Receive a message from a queue.
myNewQueue.ReceiveMessage()
Return
End Sub
' Creates a new queue.
Public Shared Sub CreateQueue(queuePath As String)
Try
If Not MessageQueue.Exists(queuePath) Then
MessageQueue.Create(queuePath)
Else
Console.WriteLine((queuePath + " already exists."))
End If
Catch e As MessageQueueException
Console.WriteLine(e.Message)
End Try
End Sub
' Sends an Order to a queue.
Public Sub SendMessage()
Try
' Create a new order and set values.
Dim sentOrder As New Order()
sentOrder.orderId = 3
sentOrder.orderTime = DateTime.Now
' Connect to a queue on the local computer.
Dim myQueue As New MessageQueue(".\myQueue")
' Create the new order.
Dim myMessage As New Message(sentOrder)
' Send the order to the queue.
myQueue.Send(myMessage)
Catch e As ArgumentException
Console.WriteLine(e.Message)
End Try
Return
End Sub
' Receives a message containing an order.
Public Sub ReceiveMessage()
' Connect to the a queue on the local computer.
Dim myQueue As New MessageQueue(".\myQueue")
' Set the formatter to indicate body contains an Order.
myQueue.Formatter = New XmlMessageFormatter(New Type() {GetType(Order)})
Try
' Receive and format the message.
Dim myMessage As Message = myQueue.Receive()
Dim myOrder As Order = CType(myMessage.Body, Order)
' Display message information.
Console.WriteLine(("Order ID: " + myOrder.orderId.ToString()))
Console.WriteLine(("Sent: " + myOrder.orderTime.ToString()))
' Handle invalid serialization format.
Catch e As InvalidOperationException
Console.WriteLine(e.Message)
End Try
' Catch other exceptions as necessary.
Return
End Sub
End Class
注解
和TargetTypeNamesTargetTypes属性都告诉格式化程序反序列化消息时要尝试匹配的架构。 这允许格式化程序解释消息正文。
消息正文中序列化的实例必须符合类型数组中表示的架构之一。 使用 Receive 该方法读取消息时，该方法将创建一个与标识的架构相对应的类型的对象，并将消息正文读入其中。
从队列中读取时，只需要设置两个属性中的一个，但你可以同时设置这两个属性。 类型集是两个属性的组合集。 要使用的属性的决定特定于应用程序。 如果消息正文包含一个类型，其架构与任一属性的数组中的任何类型不匹配，则读取消息时将引发异常。
仅当从队列中读取时，才需要目标类型。 TargetTypeNames不需要将和TargetTypes属性设置为写入队列。
指定 TargetTypes 类型时（而不是 TargetTypeNames）在编译时（而不是读取时间）进行检查，从而减少错误的可能性。
使用TargetTypes时，可以通过 C# 代码TargetTypes = new Type[]{typeof(MyClass), typeof (MyOtherClass)};演示的方式将每个对象（例如）MyClass添加到列表中。
