MessagePriority 枚举
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。
指定消息队列在消息传递到队列的过程中应用于该消息的优先级,以及指定何时将消息插入目标队列。
public enum class MessagePriority
public enum MessagePriority
type MessagePriority =
Public Enum MessagePriority
- 继承
字段
AboveNormal | 4 | |
High | 5 | 高消息优先级。 |
Highest | 7 | 最高消息优先级。 |
Low | 2 | 低消息优先级。 |
Lowest | 0 | 最低消息优先级。 |
Normal | 3 | 普通消息优先级。 |
VeryHigh | 6 | 位于 |
VeryLow | 1 | 位于 |
示例
以下示例将两条不同优先级的消息发送到队列,并随后检索它们。
#using <system.dll>
#using <system.messaging.dll>
using namespace System;
using namespace System::Messaging;
/// <summary>
/// Provides a container class for the example.
/// </summary>
ref class MyNewQueue
{
//**************************************************
// Sends a string message to a queue.
//**************************************************
public:
void SendMessage( MessagePriority priority, String^ messageBody )
{
// Connect to a queue on the local computer.
MessageQueue^ myQueue = gcnew MessageQueue( ".\\myQueue" );
// Create a new message.
Message^ myMessage = gcnew Message;
if ( priority > MessagePriority::Normal )
{
myMessage->Body = "High Priority: {0}",messageBody;
}
else
{
myMessage->Body = messageBody;
}
// Set the priority of the message.
myMessage->Priority = priority;
// Send the Order to the queue.
myQueue->Send( myMessage );
return;
}
//**************************************************
// Receives a message.
//**************************************************
void ReceiveMessage()
{
// Connect to the a queue on the local computer.
MessageQueue^ myQueue = gcnew MessageQueue( ".\\myQueue" );
// Set the queue to read the priority. By default, it
// is not read.
myQueue->MessageReadPropertyFilter->Priority = true;
// Set the formatter to indicate body contains a String^.
array<Type^>^ p = gcnew array<Type^>(1);
p[ 0 ] = String::typeid;
myQueue->Formatter = gcnew XmlMessageFormatter( p );
try
{
// Receive and format the message.
Message^ myMessage = myQueue->Receive();
// Display message information.
Console::WriteLine( "Priority: {0}",
myMessage->Priority );
Console::WriteLine( "Body: {0}",
myMessage->Body );
}
catch ( MessageQueueException^ )
{
// Handle Message Queuing exceptions.
}
// Handle invalid serialization format.
catch ( InvalidOperationException^ e )
{
Console::WriteLine( e->Message );
}
// Catch other exceptions as necessary.
return;
}
};
//**************************************************
// Provides an entry point into the application.
//
// This example sends and receives a message from
// a queue.
//**************************************************
int main()
{
// Create a new instance of the class.
MyNewQueue^ myNewQueue = gcnew MyNewQueue;
// Send messages to a queue.
myNewQueue->SendMessage( MessagePriority::Normal, "First Message Body." );
myNewQueue->SendMessage( MessagePriority::Highest, "Second Message Body." );
// Receive messages from a queue.
myNewQueue->ReceiveMessage();
myNewQueue->ReceiveMessage();
return 0;
}
using System;
using System.Messaging;
namespace MyProject
{
/// <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();
// Send messages to a queue.
myNewQueue.SendMessage(MessagePriority.Normal, "First Message Body.");
myNewQueue.SendMessage(MessagePriority.Highest, "Second Message Body.");
// Receive messages from a queue.
myNewQueue.ReceiveMessage();
myNewQueue.ReceiveMessage();
return;
}
//**************************************************
// Sends a string message to a queue.
//**************************************************
public void SendMessage(MessagePriority priority, string messageBody)
{
// Connect to a queue on the local computer.
MessageQueue myQueue = new MessageQueue(".\\myQueue");
// Create a new message.
Message myMessage = new Message();
if(priority > MessagePriority.Normal)
{
myMessage.Body = "High Priority: " + messageBody;
}
else
{
myMessage.Body = messageBody;
}
// Set the priority of the message.
myMessage.Priority = priority;
// Send the Order to the queue.
myQueue.Send(myMessage);
return;
}
//**************************************************
// Receives a message.
//**************************************************
public void ReceiveMessage()
{
// Connect to the a queue on the local computer.
MessageQueue myQueue = new MessageQueue(".\\myQueue");
// Set the queue to read the priority. By default, it
// is not read.
myQueue.MessageReadPropertyFilter.Priority = true;
// Set the formatter to indicate body contains a string.
myQueue.Formatter = new XmlMessageFormatter(new Type[]
{typeof(string)});
try
{
// Receive and format the message.
Message myMessage = myQueue.Receive();
// Display message information.
Console.WriteLine("Priority: " +
myMessage.Priority.ToString());
Console.WriteLine("Body: " +
myMessage.Body.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
'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()
' Send messages to a queue.
myNewQueue.SendMessage(MessagePriority.Normal, "First Message Body.")
myNewQueue.SendMessage(MessagePriority.Highest, "Second Message Body.")
' Receive messages from a queue.
myNewQueue.ReceiveMessage()
myNewQueue.ReceiveMessage()
Return
End Sub
' Sends a string message to a queue.
Public Sub SendMessage(priority As MessagePriority, messageBody As String)
' Connect to a queue on the local computer.
Dim myQueue As New MessageQueue(".\myQueue")
' Create a new message.
Dim myMessage As New Message()
If priority > MessagePriority.Normal Then
myMessage.Body = "High Priority: " + messageBody
Else
myMessage.Body = messageBody
End If
' Set the priority of the message.
myMessage.Priority = priority
' Send the Order to the queue.
myQueue.Send(myMessage)
Return
End Sub
' Receives a message.
Public Sub ReceiveMessage()
' Connect to the a queue on the local computer.
Dim myQueue As New MessageQueue(".\myQueue")
' Set the queue to read the priority. By default, it
' is not read.
myQueue.MessageReadPropertyFilter.Priority = True
' Set the formatter to indicate body contains a string.
myQueue.Formatter = New XmlMessageFormatter(New Type() {GetType(String)})
Try
' Receive and format the message.
Dim myMessage As Message = myQueue.Receive()
' Display message information.
Console.WriteLine(("Priority: " + myMessage.Priority.ToString()))
Console.WriteLine(("Body: " + myMessage.Body.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
MessagePriority枚举由Message类的 Priority 属性使用。 此属性影响消息队列在路由和到达目标时处理消息的方式。 在路由过程中,优先级高的消息具有优先权,将会插入到目标队列的队首。 而具有相同优先级的消息则会按照到达的先后时间插入到队列中。
当消息队列将消息路由到公共队列时,消息的优先级将添加到公共队列 (可通过类的 BasePriority 属性) 访问MessageQueue的优先级。 队列的优先级对消息在队列中的放置方式没有影响,只影响消息队列在路由过程中处理消息的方式。
基本优先级仅适用于公共队列。 对于专用队列,基本优先级始终为零。
只能为非事务性消息设置有意义的优先级。 消息队列自动将事务消息的优先级设置为 Lowest
,这会导致忽略事务性消息优先级。
适用于
另请参阅
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