CrossPlatformInput class not within the UnityStandardAssets namespace

My Unity scripts require the cross platform input classes. First they were called in the usual way.

using UnityStandardAssets.CrossPlatformInput;

This worked for a long time. But recently all scripts that had the above statement gave this error.

Assets/Standard Assets/Characters/ThirdPersonCharacter/Scripts/ThirdPersonUserControl.cs(3,27): error CS0234: The type or namespace name `CrossPlatformInput' does not exist in the namespace `UnityStandardAssets'. Are you missing an assembly reference?

Now the project doesn’t compile…

I googled and tried importing the scripts and assets again but nothing worked.
Further search showed that this CrossPlatformInput class is under ‘UnitySampleAssets’ and not under ‘UnityStandardAssets’.

How can I resolve this error?

Further search showed that this CrossPlatformInput class is under ‘UnitySampleAssets’ and not under 'UnityStandardAssets’” So you need to add an assembly reference, like the error message says:

using UnitySampleAssets;

Depois de vários dias a procura do concerto desse erro, finamente encontrei. Obrigado.

How to add a reference to UNIT in C #

tell me how you solved the problem?