How to redirect to home page on "Cancel" button click

Hi,

I have created a web part for office 365 developed using sandbox solution on Sharepoint foundation 2013.

On "Cancel" button click i want to redirect user to another page(Home page) using C# only.

i used some methods like 

Context.Response.Redirect(SPContext.Current.Web.Url.ToString() + "/Home.aspx");  

but its not working. No methods which includes context or HttpContext is not working.

Please, tell me how can i redirect user to site home page.