StackExchange.Redis Cannot access a disposed object

StackExchange.Redis is a popular library used for interacting with Redis, a high-performance in-memory data structure store. However, sometimes when working with StackExchange.Redis, you may encounter the exception "Cannot access a disposed object". In this article, we will explore the causes of this exception and how to handle it.

Understanding the Exception

The "Cannot access a disposed object" exception occurs when you try to access an object that has already been disposed. In the context of StackExchange.Redis, this typically happens when you try to access the Redis database or a specific Redis operation after the connection has been closed or disposed.

Common Causes

1. Closing or disposing the Connection

One common cause of this exception is closing or disposing the connection to Redis before performing any operations. Let's take a look at an example:

using StackExchange.Redis;
public class RedisService
    private ConnectionMultiplexer _connection;
    public RedisService(string connectionString)
        _connection = ConnectionMultiplexer.Connect(connectionString);
    public void CloseConnection()
        _connection.Close();
    public void SetValue(string key, string value)
        IDatabase db = _connection.GetDatabase();
        db.StringSet(key, value);
    public string GetValue(string key)
        IDatabase db = _connection.GetDatabase();
        return db.StringGet(key);

In the code above, we have a RedisService class that establishes a connection to Redis and provides methods to set and get values. However, if we call the CloseConnection method before calling GetValue, we will encounter the "Cannot access a disposed object" exception.

2. Using the Connection in an Async Context

Another common cause of this exception is using the connection asynchronously without properly awaiting the operations. Let's consider the following example:

public async Task<string> GetValueAsync(string key)
    IDatabase db = _connection.GetDatabase();
    return await db.StringGetAsync(key);

In the code above, if we don't properly await the StringGetAsync operation, there is a chance that the connection could be closed or disposed before the result is retrieved, leading to the exception.

Handling the Exception

To handle the "Cannot access a disposed object" exception, you need to ensure that the connection is still valid before performing any Redis operations. Here are some recommended approaches:

1. Re-establish the Connection

If you have closed or disposed the connection, you need to re-establish it before performing any operations. You can modify the RedisService class as follows:

public void SetValue(string key, string value)
    if (!_connection.IsConnected)
        _connection = ConnectionMultiplexer.Connect(_connection.Configuration);
    IDatabase db = _connection.GetDatabase();
    db.StringSet(key, value);
public string GetValue(string key)
    if (!_connection.IsConnected)
        _connection = ConnectionMultiplexer.Connect(_connection.Configuration);
    IDatabase db = _connection.GetDatabase();
    return db.StringGet(key);

In the code above, we check if the connection is still connected before performing any Redis operations. If the connection is closed, we re-establish it using the same configuration.

2. Properly Await Asynchronous Operations

When using asynchronous operations, ensure that you properly await the operations before continuing. Here's an updated version of the GetValueAsync method:

public async Task<string> GetValueAsync(string key)
    IDatabase db = _connection.GetDatabase();
    var result = await db.StringGetAsync(key);
    return result.ToString();

In the code above, we correctly await the StringGetAsync operation and convert the result to a string before returning it.

Conclusion

In this article, we have explored the "Cannot access a disposed object" exception in StackExchange.Redis. We have learned about the common causes of this exception and how to handle it by re-establishing the connection or properly awaiting asynchronous operations. By following these recommendations, you can avoid encountering this exception and ensure the smooth operation of your Redis-based applications.

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