Check User Has Write Permission on Folder C#

GetAccessControl

GetAccessControl: returns the Windows access control list (ACL) for a directory
GetAccessRules: gets a collection of the access rules associated with the specified security identifier

Example: check write permission on folder

public static bool HasWritePermission(string dir)

        { 
            bool Allow = false; 
            bool Deny = false;
            DirectorySecurity  acl = null;
            try
            {
                acl = Directory.GetAccessControl(dir);
            }
            catch (System.IO.DirectoryNotFoundException)
            {
                throw new Exception("DirectoryNotFoundException"); 
            }
            if (acl == null) 
                return false; 
            AuthorizationRuleCollection  arc = acl.GetAccessRules(true, true,typeof(System.Security.Principal.SecurityIdentifier)); 
            if (arc == null) 
                return false; 
            foreach (FileSystemAccessRule rule in arc) 
            { 
                if ((FileSystemRights.Write & rule.FileSystemRights) !=FileSystemRights.Write) 
                    continue; 
                if (rule.AccessControlType == AccessControlType.Allow)
                    Allow = true; 
                else if (rule.AccessControlType == AccessControlType.Deny)
                    Deny = true; 
            }
            return Allow && !Deny; 
        }