How to make a very simple page password protected by ASP.Net

Question

I am looking for a very simple solution to password protect ASP.Net pages.

I found exactly what I am looking for here , but it is in ASP, and I don’t know the syntax to convert it to ASP.Net,

It simply creates a temporary cookie that expires as soon as they close their browser window.

I do not want to store username / password in db. Sometimes I will change the password manually.

Just helping me convert the following code to ASP.Net would be great!

This happens on the logon.aspx page and pulls values ​​from the form.

Username="Administrator"
Password="Admin"
Validated = "OK"

if Strcomp(Request.Form("User"),Username,1)=0 AND Request.Form("password") = Password then
    Response.Cookies("ValidUser") = Validated

    If (Request.QueryString("from")<>"") then
        Response.Redirect Request.QueryString("from")
    else
      Response.Redirect "MyPage.aspx"
    End if    
Else
    If Request.Form("User") <> "" then
        Response.Write "<h3>Authorization Failed.</h3>" & "<br>" & _ "Please try again.<br>&#xa0;<br>"
    End if
End if

This page is password protected to confirm that a cookie has been created.

Validated = "OK"

if Request.Cookies("ValidUser") <> Validated then
dim s
s = "http://"
s = s & Request.ServerVariables("HTTP_HOST")
s = s & Request.ServerVariables("URL")

if Request.QueryString.Count > 0 THEN
    s = s & "?" & Request.QueryString 
end if

Response.Redirect "Logon.aspx"
End if

Answer 1

web.config.