Pass extra variable to event handler in C#

[AbrhamSO]

my application fires an event on data received from a serial port using this:
sr.DataReceived += new SerialDataRecei vedEventHandler (DataReceivedHa ndler);
And i handle the data received using:
private static void DataReceivedHan dler(object sender, SerialDataRecei vedEventArgs e)
{
try
{
SerialPort sp = (SerialPort)sen der;
MessageBox.Show (sp.ReadExistin g());
}
catch (Exception ex)
{
MessageBox.Show (ex.Message);
}
}
how to pass decimal value to the event handler DataReceivedHan dler?