XmlMessageFormatter.TargetTypes 属性
定义
指定可能的类型集,这些类型将由格式化程序从提供的消息进行反序列化。Specifies the set of possible types that will be deserialized by the formatter from the message provided.
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, set
Public Property TargetTypes As Type()
属性值
- Type[]
Type 类型的数组,指定当读取消息时从消息体反序列化的对象的类型。An array of type Type that specifies the types of objects to deserialize from the message body when reading the message.
- 属性
例外
TargetTypes 属性为 null。The TargetTypes property is null.
示例
下面的代码示例在队列中发送和接收包含订单的消息。The following code example sends and receives a message that contains an order to and from a queue.
#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
TargetTypeNames和属性都 TargetTypes 告诉格式化程序在反序列化消息时要尝试匹配的架构。Both the TargetTypeNames and TargetTypes properties tell the formatter what schemas to attempt to match when deserializing a message. 这允许格式化程序解释消息正文。This allows the formatter to interpret the message body.
在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。The instance serialized in the message body must comply with one of the schemas represented in the type array. 使用方法读取消息时 Receive ,方法会创建一个类型为的对象,该对象对应于标识的架构并将消息正文读入其中。When you read the message using the Receive method, the method creates an object of the type that corresponds to the schema identified and reads the message body into it.
从队列中读取时,只需设置这两个属性中的一个,但可以同时设置这两个属性。Only one of the two properties needs to be set when reading from the queue, but you can set both. 类型集是这两个属性的组合集。The set of types is the combined set from the two properties. 要使用哪个属性取决于您的应用程序。The decision of which property to use is specific to your application. 如果消息正文包含一个类型,该类型的架构与任一属性的数组中的任何类型都不匹配,则在读取消息时将引发异常。If the message body contains a type whose schema does not match any of the types in the array for either property, an exception will be thrown when the message is read.
只有从队列中读取时才需要目标类型。The target types are only required when reading from the queue. TargetTypeNames和 TargetTypes 属性不需要设置为写入队列。The TargetTypeNames and TargetTypes properties do not need to be set to write to the queue.
当指定 TargetTypes 而不是时 TargetTypeNames ,将在编译时(而不是读取时间)检查类型存在,从而降低错误的可能性。When specifying TargetTypes rather than TargetTypeNames, type existence is checked at compile time rather than read time, reducing possibility for error.
使用时 TargetTypes ,可以将每个对象 (例如,以 MyClass c # 代码演示的方式将) 到列表 TargetTypes = new Type[]{typeof(MyClass), typeof (MyOtherClass)}; 。When using TargetTypes, you can add each object (for example, MyClass) to the list in a way demonstrated by the C# code TargetTypes = new Type[]{typeof(MyClass), typeof (MyOtherClass)};.