使用 RabbitMQ 是一种常见的消息队列解决方案，用于构建可扩展的分布式应用程序。下面我将详细讲解如何在 .NET 中使用 RabbitMQ，包括常用功能和示例源代码。

1. 安装 RabbitMQ

首先，你需要安装 RabbitMQ 服务器。你可以从官方网站下载 RabbitMQ，并按照官方文档进行安装和配置。安装完成后，确保 RabbitMQ 服务器正在运行。

2. 使用 RabbitMQ 基本功能

2.1. 发布和订阅消息

RabbitMQ 的基本工作方式是生产者将消息发布到交换机，然后由消费者从队列中订阅消息。以下是一个示例：

// 生产者
var factory = new ConnectionFactory() { HostName = "localhost" };
using (var connection = factory.CreateConnection())
using (var channel = connection.CreateModel())
{
    channel.ExchangeDeclare(exchange: "logs", type: ExchangeType.Fanout);
    var message = "Hello, RabbitMQ!";
    var body = Encoding.UTF8.GetBytes(message);
    channel.BasicPublish(exchange: "logs", routingKey: "", basicProperties: null, body: body);
    Console.WriteLine("Sent: {0}", message);
}

// 消费者
var factory = new ConnectionFactory() { HostName = "localhost" };
using (var connection = factory.CreateConnection())
using (var channel = connection.CreateModel())
{
    channel.ExchangeDeclare(exchange: "logs", type: ExchangeType.Fanout);
    var queueName = channel.QueueDeclare().QueueName;
    channel.QueueBind(queue: queueName, exchange: "logs", routingKey: "");
    
    var consumer = new EventingBasicConsumer(channel);
    consumer.Received += (model, ea) =>
    {
        var body = ea.Body.ToArray();
        var message = Encoding.UTF8.GetString(body);
        Console.WriteLine("Received: {0}", message);
    };
    channel.BasicConsume(queue: queueName, autoAck: true, consumer: consumer);
}

上述代码中，生产者将消息发布到名为 "logs" 的交换机，而消费者从该交换机创建一个队列并订阅消息。

2.2. 路由消息

RabbitMQ 允许你使用路由键将消息路由到特定队列。以下是一个示例：

// 生产者
var factory = new ConnectionFactory() { HostName = "localhost" };
using (var connection = factory.CreateConnection())
using (var channel = connection.CreateModel())
{
    channel.ExchangeDeclare(exchange: "direct_logs", type: ExchangeType.Direct);
    var severity = "info";
    var message = "Informational message.";
    var body = Encoding.UTF8.GetBytes(message);
    channel.BasicPublish(exchange: "direct_logs", routingKey: severity, basicProperties: null, body: body);
    Console.WriteLine("Sent: [{0}] {1}", severity, message);
}

// 消费者
var factory = new ConnectionFactory() { HostName = "localhost" };
using (var connection = factory.CreateConnection())
using (var channel = connection.CreateModel())
{
    channel.ExchangeDeclare(exchange: "direct_logs", type: ExchangeType.Direct);
    var queueName = channel.QueueDeclare().QueueName;
    var severity = "info";
    channel.QueueBind(queue: queueName, exchange: "direct_logs", routingKey: severity);

    var consumer = new EventingBasicConsumer(channel);
    consumer.Received += (model, ea) =>
    {
        var body = ea.Body.ToArray();
        var message = Encoding.UTF8.GetString(body);
        Console.WriteLine("Received: [{0}] {1}", severity, message);
    };
    channel.BasicConsume(queue: queueName, autoAck: true, consumer: consumer);
}

在此示例中，消息被路由到具有特定路由键 "info" 的队列。

2.3. 主题交换机

RabbitMQ 还支持主题交换机，允许你根据模式匹配消息的路由键进行订阅。以下是一个示例：

// 生产者
var factory = new ConnectionFactory() { HostName = "localhost" };
using (var connection = factory.CreateConnection())
using (var channel = connection.CreateModel())
{
    channel.ExchangeDeclare(exchange: "topic_logs", type: ExchangeType.Topic);
    var routingKey = "kern.critical";
    var message = "Critical kernel error.";
    var body = Encoding.UTF8.GetBytes(message);
    channel.BasicPublish(exchange: "topic_logs", routingKey: routingKey, basicProperties: null, body: body);
    Console.WriteLine("Sent: [{0}] {1}", routingKey, message);
}

// 消费者
var factory = new ConnectionFactory() { HostName = "localhost" };
using (var connection = factory.CreateConnection())
using (var channel = connection.CreateModel())
{
    channel.ExchangeDeclare(exchange: "topic_logs", type: ExchangeType.Topic);
    var queueName = channel.QueueDeclare().QueueName;
    var routingKey = "kern.*";
    channel.QueueBind(queue: queueName, exchange

: "topic_logs", routingKey: routingKey);

    var consumer = new EventingBasicConsumer(channel);
    consumer.Received += (model, ea) =>
    {
        var body = ea.Body.ToArray();
        var message = Encoding.UTF8.GetString(body);
        Console.WriteLine("Received: [{0}] {1}", routingKey, message);
    };
    channel.BasicConsume(queue: queueName, autoAck: true, consumer: consumer);
}

在此示例中，消息被路由到匹配模式 "kern.*" 的队列。

3. 其他功能

RabbitMQ 还支持消息持久化、RPC（远程过程调用）、集群和安全等功能。你可以根据项目需求探索这些功能，并使用RabbitMQ的官方文档和.NET客户端库来实现。

上述示例涵盖了RabbitMQ的一些常见用例，希望可以帮助你入门RabbitMQ并在.NET应用程序中使用它。