Visual Studio WITH C# KEY BINDINGS _ hotkey

To answer the specific question, in C# you are likely to be using the C# keyboard mapping scheme, which will use these hotkeys by default:

Ctrl+E, Ctrl+D to format the entire document.
Ctrl+E, Ctrl+F to format the selection.

You can change these in Tools > Options > Environment -> Keyboard (either by selecting a different "keyboard mapping scheme", or binding individual keys to the commands "Edit.FormatDocument" and "Edit.FormatSelection").

If you have not chosen to use the C# keyboard mapping scheme, then you may find the key shortcuts are different. For example, if you are not using the C# bindings, the keys are likely to be:

Ctrl + K + D (Entire document)
Ctrl + K + F (Selection only)

To find out which key bindings apply in YOUR copy of Visual Studio, look in the Edit > Advanced menu - the keys are displayed to the right of the menu items, so it's easy to discover what they are on your system.