File: Core\CSharp\System\Windows\Input\MouseWheelEventHandler.cs
Project: wpf\src\PresentationCore.csproj (PresentationCore)

using System;
namespace System.Windows.Input
{
    /// <summary>
    ///     The delegate to use for handlers that receive MouseWheelEventArgs.
    /// </summary>
    public delegate void MouseWheelEventHandler(object sender, MouseWheelEventArgs e);
}