How to implement csrf code into baseclass.cs in ASP.NET.

baseclass.cs

baseclass.cs

public class BaseClass : System.Web.UI.Page, IDisposable
{

private const string AntiXsrfTokenKey = "__AntiXsrfToken";
private const string AntiXsrfUserNameKey = "__AntiXsrfUserName";
private string _antiXsrfTokenValue;

protected override void OnInit(EventArgs e)
{
    // The code below helps to protect against XSRF attacks
    var requestCookie = Request.Cookies[AntiXsrfTokenKey];
    Guid requestCookieGuidValue;
    if (requestCookie != null && Guid.TryParse(requestCookie.Value, out requestCookieGuidValue))
    {
        // Use the Anti-XSRF token from the cookie
        _antiXsrfTokenValue = requestCookie.Value;
        Page.ViewStateUserKey = _antiXsrfTokenValue;
    }
    else
    {
        // Generate a new Anti-XSRF token and save to the cookie
        _antiXsrfTokenValue = Guid.NewGuid().ToString("N");
        Page.ViewStateUserKey = _antiXsrfTokenValue;

        var responseCookie = new HttpCookie(AntiXsrfTokenKey)
        {
            HttpOnly = true,
            Value = _antiXsrfTokenValue
        };
        if (FormsAuthentication.RequireSSL && Request.IsSecureConnection)
        {
            responseCookie.Secure = true;
        }
        Response.Cookies.Set(responseCookie);
    }

    Page.PreLoad += master_Page_PreLoad;
}

protected void master_Page_PreLoad(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        // Set Anti-XSRF token
        ViewState[AntiXsrfTokenKey] = Page.ViewStateUserKey;
        ViewState[AntiXsrfUserNameKey] = Context.User.Identity.Name ?? String.Empty;
    }
    else
    {
        // Validate the Anti-XSRF token
        if ((string)ViewState[AntiXsrfTokenKey] != _antiXsrfTokenValue
            || (string)ViewState[AntiXsrfUserNameKey] != (Context.User.Identity.Name ?? String.Empty))
        {
            throw new InvalidOperationException("Validation of Anti-XSRF token failed.");
        }
    }
}