Leandro Díaz Guerra's Blog

I’ve been working on how to recycle the current application pool for my ASP .NET application.

There are 3 steps for doing this:

1. Verify if application is running on IIS that supports application pools (if not, there’s nothing to recycle).
2. Get application pool name (obtained from the DirectoryServices entry corresponding to our virtual directory).
3. Invoke Recycle method in the DirectoryServices entry corresponding to the application pool.

I divided the code into this 3 steps, the RecycleApplicationPool method can be used separately for recycling any application pool (by knowing only its name). The RecycleCurrentApplicationPool method returns a boolean value indicating if the application pool was recycled.

public static class ApplicationPoolRecycle
{
    /// <summary>Attempts to recycle current application pool</summary>
    /// <returns>Boolean indicating if application pool was successfully recycled</returns>
    public static bool RecycleCurrentApplicationPool()
    {
        try
        {
            // Application hosted on IIS that supports App Pools, like 6.0 and 7.0
            if (IsApplicationRunningOnAppPool())
            {
                // Get current application pool name
                string appPoolId = GetCurrentApplicationPoolId();
                // Recycle current application pool
                RecycleApplicationPool(appPoolId);
                return true;
            }
            else
                return false;
        }
        catch
        {
            return false;
        }
    }
    private static bool IsApplicationRunningOnAppPool()
    {
        // Application is not hosted on IIS
        if (!AppDomain.CurrentDomain.FriendlyName.StartsWith("/LM/"))
            return false;
        // Application hosted on IIS that doesn't support App Pools, like 5.1
        else if (!DirectoryEntry.Exists("IIS://Localhost/W3SVC/AppPools"))
            return false;
        else
            return true;
    }
    private static string GetCurrentApplicationPoolId()
    {
        string virtualDirPath = AppDomain.CurrentDomain.FriendlyName;
        virtualDirPath = virtualDirPath.Substring(4);
        int index = virtualDirPath.Length + 1;
        index = virtualDirPath.LastIndexOf("-", index - 1, index - 1);
        index = virtualDirPath.LastIndexOf("-", index - 1, index - 1);
        virtualDirPath = "IIS://localhost/" + virtualDirPath.Remove(index);
        DirectoryEntry virtualDirEntry = new DirectoryEntry(virtualDirPath);
        return virtualDirEntry.Properties["AppPoolId"].Value.ToString();
    }
    private static void RecycleApplicationPool(string appPoolId)
    {
        string appPoolPath = "IIS://localhost/W3SVC/AppPools/" + appPoolId;
        DirectoryEntry appPoolEntry = new DirectoryEntry(appPoolPath);
        appPoolEntry.Invoke("Recycle");
    }
}