superlogical/MonoTouch.SlideMenu — pull request #1 by ghuntley (2013-02-04 05:03:07+00:00)
Title: dismiss keyboard when menu is activated

Forces the contentViewController to resign any first registered first responders upon activation of the menu, which in affect forces the keyboard to be close if open.

endEditing:
Causes the view (or one of its embedded text fields) to resign the first responder status.

- (BOOL)endEditing:(BOOL)force

Parameters
Specify YES to force the first responder to resign, regardless of whether it wants to do so.

Return Value
YES if the view resigned the first responder status or NO if it did not.

Discussion
This method looks at the current view and its subview hierarchy for the
text field that is currently the first responder. If it finds one, it asks
that text field to resign as first responder. If the force parameter is set
to YES, the text field is never even asked; it is forced to resign.

http://developer.apple.com/library/ios/#documentation/uikit/reference/uiview_class/uiview/uiview.html