Determine if a user belongs to a role?

cq_blue

protected void Page_Load (object sender, EventArgs e)
    {
        RolePrincipal p = (RolePrincipal) User;
        string [] roles = p.GetRoles ();
        foreach (string s in roles)
        {
            Response.Write (s + "<br>");
        }
        if (HttpContext.Current.User.IsInRole ("PurchaseAdmin"))
        {
            string url;
            url = "~ / Default1.aspx";
            Response.Redirect (this.ResolveUrl (url));
                   }
    }

The following error occurred during operation, I seem to have solved it before, but the problem cannot be solved after reinstalling the operating system. ?????
The error is as follows:
Objects of type "System.Security.Principal.WindowsPrincipal" cannot be cast to type "System.Web.Security.RolePrincipal".

everever30

((RolePrincipal) Page.User.Identity) .IsInRole

cq_blue

I solved it myself, it turned out that I removed the enable windows authentication and role authentication in WEB.CONFIG, so it reported an error. It was normal after it was enabled.

cq_blue

The code is improved (purpose: users belong to different roles and then go to different pages).

protected void Page_Load (object sender, EventArgs e)
    {
        RolePrincipal p = (RolePrincipal) User;
        string [] roles = p.GetRoles ();
        foreach (string s in roles)
        {
            Response.Write (s + "<br>");
            string str1 = "Purchasing system administrator group";
            string str2 = s;
            if (str2.IndexOf (str1)> -1)
            {
                //Response.Write("contains ");
                string url;
                url = "~ / Default1.aspx";
                Response.Redirect (this.ResolveUrl (url));
            }
         }
     }