Am I looking for a shortcut key to switch from a Behind code file (a.cs) to an HTML page source page (a.aspx)? I could not find a direct way to handle this!
F7 → Switch between .ASPX and .ASPX.CS (Code behind) Shift + F7 → Switch between .ASPX Design View and Source View
@JasonReis, you're right
Try Shift + F7. Usually, using the shift + shortcut key performs the opposite function in visual studio.
F7 .aspx .cs.