Use the Object type for the first parameter of an event.

Remarks

Microsoft recommends that there should always be two parameters for all events. The first parameter of the event should be of type Object. Microsoft recommends that you always use an Object, even if it is possible to use a more specific type.

Resolution

Modify the event to have the event sender as the first parameter, and make it an object type. For example, the following event handlers follow Microsoft's guidelines:

' VB
Public Delegate Sub MouseEventHandler(sender As Object, e As EventArgs)

// C#
public delegate void MouseEventHandler(object sender, EventArgs e);

See Also

Event Usage Guidelines

Total .NET Analyzer Event Argument Count rule

Total .NET Analyzer First Event Argument Type rule