The security validation for this page is invalid.

When you working with sharepoint and you encounter with this error:

The security validation for this page is invalid. Click Back in your Web browser, refresh the page, and try your operation again:

Solution is easy:

set “AllowUnsafeUpdates” propery true.

Example:

Guid webID = SPContext.Current.Web.ID;

Guid siteID = SPContext.Current.Site.ID;

SPSecurity.RunWithElevatedPrivileges(delegate()

    using (SPSite site = new SPSite(siteID))

        site.AllowUnsafeUpdates = true;

        using (SPWeb web = site.OpenWeb(webID))

        {
            web.AllowUnsafeUpdates = true;
            //your code here...

About bpostaci
Escalation Engineer in Microsoft.