Apply the use of the "using" directive where needed (as opposed to where not needed).
There's nothing in the file (that you have posted) with the MainClass that requires the following:
Code:
using SdlDotNet;
using SdlDotNet.Core;
using SdlDot.Graphics;
using System;
using System.Drawing;
However, within the file that you define TroutWars, you might find it helpful to put those "using" directives at the beginning of the file.
As for QuitEventArgs, it is part of the SdlDotNet.Core namespace.
P.S. Who knows... I could be wrong... I'm not a C# developer.