//Set some custom parameters for this uploader instance, to send along with the upload queue.
var fileUploader2 = new FileUploader
{
    CustomParameters = new Dictionary<string, object>
    {
        {"MyParam1", "test"},
        {"MyParam2", true},
        {"MyParam3", 50}
    }
};

//Or set them like this:
fileUploader.CustomParameters.Add("MyParam1", "test");
fileUploader.CustomParameters.Add("MyParam2", true);
fileUploader.CustomParameters.Add("MyParam3", 50);


//In server-side events, you can examine your custom parameters via e.Queue.CustomParameters property
//and take an action depending on them.
fileUploader.Uploading += (sender, e) =>
{
    //Casting can cause problems, e.g. (int)e.Queue.CustomParameters["MyParam3"]
    //especially for int types as when JsonDeserializer is deserializing numbers from a dictionary,
    //it treats them as long (int64).
    //So use methods of Convert to avoid casting problems.

    var myParam1 = Convert.ToString(e.Queue.CustomParameters["MyParam1"]);
    var myParam2 = Convert.ToBoolean(e.Queue.CustomParameters["MyParam2"]);
    var myParam3 = Convert.ToInt32(e.Queue.CustomParameters["MyParam3"]);
};