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I need to implement CSRF in web forms to prevent unwanted cross site request.

[edit]Added the word "Protection" to subject line to prevent "malicious coder" kicking, and added code block to "What have you tried" section - OriginalGriff[/edit]

What I have tried:

I have tried below code to implement CSRF but it did not work for me.
public class CSRFBASE : System.Web.UI.Page
        private const string AntiXsrfTokenKey = "__AntiXsrfToken";
        private const string AntiXsrfUserNameKey = "__AntiXsrfUserName";
        private string _antiXsrfTokenValue;
        protected void Page_Init(object sender, 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;
                // 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;

            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;
                // 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.");
Updated 22-Apr-20 20:52pm
Kornfeld Eliyahu Peter 9-Aug-17 9:17am
Do you mean you want to implement protection from CSRF?!
Dev_TechnoLabs 9-Aug-17 9:18am

Dev_TechnoLabs 9-Aug-17 9:27am
most of the links are related to MVC. not useful for me
Kornfeld Eliyahu Peter 9-Aug-17 9:31am
Learning is always useful!!! If not other, than the existence of other technologies beyond WebForms...
And the last two (especially the last) is exactly what you are looking for... including exact code sample...
F-ES Sitecore 9-Aug-17 9:31am
So google " csfr protection webforms" or "" csfr protection webforms -mvc". Believe it or not you're not the first person to want to do this so the code is readily available if you just look for it.
Dev_TechnoLabs 6-Oct-17 7:24am
@F-ES Sitecore thanks for your good suggestion. I will definitely do that.
Use the below code:

In Design Page:
<div id="DivCSRF" runat="server"></div>

In Code Page:
Protected Sub Page_Init(ByVal sender As Object, ByVal e As EventArgs)
        DivCSRF.InnerHtml = AntiForgery.GetHtml().ToString()
    End Sub

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        DivCSRF.InnerHtml = AntiForgery.GetHtml().ToString()
        If IsPostBack Then
            Catch ex As Exception
                Response.Redirect("~/Unauthorize.aspx", False)
                Exit Sub
            End Try
        End If

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