SharePoint How to Programmatically Impersonate Users in SharePoint

Impersonating users in SharePoint will require a couple of things:

• the account that the web or console app uses has privileges to impersonate other users (typically this would be the system account)
• specific users’ user tokens

Step 1: Log in as the system account, or get a handle to the system account in your code

      string siteStr = "http://mysharepointsite/";

      //we just need to get a handle to the site for us
      //to get the system account user token
      SPSite tempSite = new SPSite(siteStr);

      SPUserToken systoken = tempSite.SystemAccount.UserToken;

      using (SPSite site = new SPSite(siteStr, systoken))
      {
         using (SPWeb web = site.OpenWeb())
         {
             //right now, logged in as Site System Account
             Console.WriteLine("Currently logged in as: " +
                              web.CurrentUser.ToString());

             //add your code here
         }
      }
      

Step 2: Before you impersonate, get the user token of the user you are switching to. For example:

      //get this current user's user token
      SPUserToken userToken = web.AllUsers[user].UserToken;

      //create an SPSite object in the context of this user
      SPSite s = new SPSite(siteStr, userToken);

      SPWeb w = s.OpenWeb();
      Console.WriteLine("Currently logged in as: " +
                        w.CurrentUser.ToString() +
                        "(" + w.CurrentUser.Name + ")"
                       );
      

Complete code follows:

Step 2: Before you impersonate, get the user token of the user you are switching to. For example:

      private static void impersonateTest()
      {
         string siteStr = "http://mysharepointsite/";
         SPSite tempSite = new SPSite(siteStr);
         SPUserToken systoken = tempSite.SystemAccount.UserToken;
         using (SPSite site = new SPSite(siteStr, systoken))
         {
             using (SPWeb web = site.OpenWeb())
             {
                 //right now, logged in as Site System Account
                 Console.WriteLine("Currently logged in as: " +
                                    web.CurrentUser.ToString());
                 switchUser(web, siteStr, "BlackNinjaSoftware/MatthewCarriere");
                 switchUser(web, siteStr, "BlackNinjaSoftware/ShereenQumsieh");
                 switchUser(web, siteStr, "BlackNinjaSoftware/DonabelSantos");
             }
         }
      }

      private static void switchUser(SPWeb web, string siteStr, string user)
      {
         //impersonate somebody else
         SPUserToken userToken = web.AllUsers[user].UserToken;
         SPSite s = new SPSite(siteStr, userToken);
         SPWeb w = s.OpenWeb();
         Console.WriteLine("Currently logged in as: " +
                           w.CurrentUser.ToString() +
                           "(" + w.CurrentUser.Name + ")"
                          );
      }