Ok I did it on my own:
Material m=new Material(URL);
process.OutputDataReceived +=(Object _sender, DataReceivedEventArgs _args)=>DoSomething(m, _sender, _args);
public void DoSomething(Material mt,object sender, DataReceivedEventArgs e)
{
MessageBox.Show("Captured Data:" + e.Data);
MessageBox.Show("My Data:" + mt.Info);
}