Reading Active Directory group users in SharePoint

Say that i have an active directory group called "Group1". I add this Group1 to a SharePoint site ( People and Group >> New User).

All the users that are part of Group1 can now access sharepoint site.

Now,for a specific custom webpart, i need to target to only users who belong to开发者_如何学编程 Group1. But when a user who belongs to Group1 logs into the sharepoint site, i am not finding a way to determine from within SharePoint context if this user belongs to Group1. Any thoughts?

Thanks, Faiz

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Use the following code to check if the current user is in the given security group:

WindowsIdentity wi = WindowsIdentity.GetCurrent();
WindowsPrincipal wp = new WindowsPrincipal(wi);
wp.IsInRole("Group1");