Sharepoint: Check if a user is member of a group

Question

how can I check if a user (not the one currently logged in) is member of a certain group? Trying to retrieve a user from a group of which he's not a member leads to an SPException, so checking for null is not possible.

So how would you solve this problem. At the moment I think about searching in the SPGroup.Users.XML string for the user's name or iterating over all the group members and checking the login names.

Update: I forgot to mention that I want to avoid the usage of exception handling to check the user's membership.

score 19 · Answer 1 · answered Dec 01 '11 at 15:39

Create an Extension class for SPUser and static method:

public static class SPUserExtension {
   public static bool InGroup(this SPUser user, SPGroup group)
      {
        return user.Groups.Cast<SPGroup>()
          .Any(g => g.ID == group.ID);
      }
   }
}

Then invoke this method on your SPUser object:

SPUser user;
SPGroup group;
//...
bool isMember = user.InGroup(group);

Alex Angas · Accepted Answer · 2009-07-02T13:04:39.567

6

I have done this by writing an extension method using LINQ. SPGroup inherits from SPPrincipal so you should be able to pass it through to the principal parameter:

public static bool Contains(this SPRoleAssignmentCollection rac, SPPrincipal principal)
{
    XElement racXml = XElement.Parse(rac.Xml);
    return racXml.Elements("permission").Any(vw => (int)vw.Attribute("memberid") == principal.ID);
}

edited Jul 02 '09 at 13:04

answered Jul 01 '09 at 09:00

Alex Angas

56,458
39
130
203

Thanks for your solution. Although I was not sure what you mean with "SPrac" so I wrote an extension method for the SPGroup class which checks the SPGroup.Users.Xml property for an user's login. – Flo Jul 02 '09 at 12:44
Sorry, find and replace gone awry. Fixed now. – Alex Angas Jul 02 '09 at 13:04

score 4 · Answer 3 · edited Jul 01 '09 at 08:53

Couple of ways. SharePoint group has an Option that can allow only the Group Owner to see the membership details or allow everyone to view the membership details. If every one is allowed you will not get the Security restriction, else you need to RunWithElevatedPrivileges, and be sure to get a New Instance of the SPSite & SPWeb to be used inside that.

Being said that below are the options:

private Boolean isUserInGroup(SPGroup oGroupToTestFor,String sUserLoginName)
    {   
        Boolean bUserIsInGroup = false;
        try
        {
            SPUser x = oGroupToTestFor.Users[sUserLoginName];
            bUserIsInGroup = true;
        }
        catch (SPException)
        {
            bUserIsInGroup = false;
        }
        return bUserIsInGroup;

    }

Another way is to

private Boolean isUserInGroup(SPGroup oGroupToTestFor, String sUserLoginName)
    {   
        Boolean bUserIsInGroup = false;

            SPUser oUser =null;
            try{
                oUser = SPContext.Current.Web.AllUsers[sUserLoginName];
                }
            catch{}
            if(oUser!=null){
            foreach (SPUser item in oGroupToTestFor.Users)
            {
                if (item.UserToken == oUser.UserToken)
                {
                    bUserIsInGroup = true;
                    break;
                }                    
            }
            }

        return bUserIsInGroup;

    }

Please note that the AllUsers collection may not contain the member unless the user has browsed the site. — Alex Nolasco, Oct 06 '09 at 21:14

score 1 · Answer 4 · answered Jun 30 '09 at 14:35

1

Have you tried using RunWithElevatedPrivileges?

SPSecurity.RunWithElevatedPrivileges(delegate()
        {
             //put your code here to get the group and test for the user
        });

answered Jun 30 '09 at 14:35

cjuk

418
5
8

No, that doesn't change anything. The indexer still throws an exception. – Flo Jun 30 '09 at 15:00
3

This should be a comment and not answer... you 'answered' with another question. – trgraglia Oct 27 '11 at 12:52

score 0 · Answer 5 · answered Jul 01 '09 at 05:50

In order to make the SPSecurity.RunWith.. work, you need to have a new instance of the SPSite and/or SPWeb object and not use the context otherwise it won't work.

Do you have the SPUser object to use? If so, you can just use the SPUser.Groups collection.

score 0 · Answer 6 · answered Dec 17 '13 at 09:28

I have implemented a simple way to check if specific user exists in a specific SharePoint group. A simple statement with linq on SPUser object.

bool userExsists = spUser.Groups.Cast<SPGroup>().Any(g => g.Name.ToLower() == spGroup.Name.ToLower());

Find the detailed post on SharePoint Core Solutions.

Sharepoint: Check if a user is member of a group

6 Answers6