使用推送技术:我是这样做的:Class with message
public class Message
{
/// <summary>
/// The name who will receive this message.
/// </summary>
public string RecipientName { get; set; }
/// <summary>
/// The message content.
/// </summary>
public string MessageContent { get; set; }
}
代表客户的类:
public class Client
{
private ManualResetEvent messageEvent = new ManualResetEvent(false);
private Queue<Message> messageQueue = new Queue<Message>();
/// <summary>
/// This method is called by a sender to send a message to this client.
/// </summary>
/// <param name="message">the new message</param>
public void EnqueueMessage(Message message)
{
lock (messageQueue)
{
messageQueue.Enqueue(message);
// Set a new message event.
messageEvent.Set();
}
}
/// <summary>
/// This method is called by the client to receive messages from the message queue.
/// If no message, it will wait until a new message is inserted.
/// </summary>
/// <returns>the unread message</returns>
public Message DequeueMessage()
{
// Wait until a new message.
messageEvent.WaitOne();
lock (messageQueue)
{
if (messageQueue.Count == 1)
{
messageEvent.Reset();
}
return messageQueue.Dequeue();
}
}
}
向客户端发送消息的类:
public class ClientAdapter
{
/// <summary>
/// The recipient list.
/// </summary>
private Dictionary<string, Client> recipients = new Dictionary<string,Client>();
/// <summary>
/// Send a message to a particular recipient.
/// </summary>
public void SendMessage(Message message)
{
if (recipients.ContainsKey(message.RecipientName))
{
Client client = recipients[message.RecipientName];
client.EnqueueMessage(message);
}
}
/// <summary>
/// Called by a individual recipient to wait and receive a message.
/// </summary>
/// <returns>The message content</returns>
public string GetMessage(string userName)
{
string messageContent = string.Empty;
if (recipients.ContainsKey(userName))
{
Client client = recipients[userName];
messageContent = client.DequeueMessage().MessageContent;
}
return messageContent;
}
/// <summary>
/// Join a user to the recipient list.
/// </summary>
public void Join(string userName)
{
recipients[userName] = new Client();
}
/// <summary>
/// Singleton pattern.
/// This pattern will ensure there is only one instance of this class in the system.
/// </summary>
public static ClientAdapter Instance = new ClientAdapter();
private ClientAdapter() { }
}
发送消息:
Message message = new Message
{
RecipientName = tbRecipientName.Text.Trim(),
MessageContent = tbMessageContent.Text.Trim()
};
if (!string.IsNullOrWhiteSpace(message.RecipientName) && !string.IsNullOrEmpty(message.MessageContent))
{
// Call the client adapter to send the message to the particular recipient instantly.
ClientAdapter.Instance.SendMessage(message);
}
接收消息(这是在测试页面中编写的 JavaScript 函数。它们在 ASPX 页面上呈现消息的内容。在这里你应该实现你的逻辑):
// This method will persist a http request and wait for messages.
function waitEvent() {
CSASPNETReverseAJAX.Dispatcher.WaitMessage("<%= Session["userName"] %>",
function (result) {
displayMessage(result);
// Keep looping.
setTimeout(waitEvent, 0);
}, function () {
// Keep looping.
setTimeout(waitEvent, 0);
});
}
// Append a message content to the result panel.
function displayMessage(message) {
var panel = document.getElementById("<%= lbMessages.ClientID %>");
panel.innerHTML += currentTime() + ": " + message + "<br />";
}
// Return a current time string.
function currentTime() {
var currentDate = new Date();
return currentDate.getHours() + ":" + currentDate.getMinutes() + ":" + currentDate.getSeconds();
}