SharePoint SPListItem 权限设置

namespace Microsoft.SharePoint
{
    using System;
    using System.Text;
    using System.Collections.Generic;
    using System.Linq;
    using Microsoft.SharePoint;

    public static class PermissionManager
    {

        //SPGroup group = web.Groups[0];
        //SPUser user = web.Users[0];
        //SPUser user2 = web.EnsureUser("mangaldas.mano");
        //SPUser user3 = web.EnsureUser("Domain Users");
        //SPPrincipal[] principals = { group, user, user2, user3 }; 

        #region Adding Permissions to an item

        /// <summary>
        /// Set Permissions
        /// </summary>
        /// <param name="item">SPListItem</param>
        /// <param name="user">SPUser</param>
        /// <param name="roleType">SPRoleType</param>
        public static void SetPermissions(SPListItem item, SPUser user, SPRoleType roleType)
        {
            if (item != null)
            {
                SPRoleDefinition roleDefinition = item.Web.RoleDefinitions.GetByType(roleType);
                SetPermissions(item, (SPPrincipal)user, roleDefinition);
            }
        }
        public static void SetPermissions(SPListItem item, SPUser user, string rolename)
        {
            if (item != null)
            {
                SPRoleDefinition roleDefinition = item.Web.RoleDefinitions[rolename];
                if (roleDefinition != null)
                    SetPermissions(item, (SPPrincipal)user, roleDefinition);
            }
        }
        public static void SetPermissions(SPListItem item, string groupName, string rolename)
        {
            if (item != null)
            {
                SPRoleDefinition roleDefinition = item.Web.RoleDefinitions[rolename];
                SPGroup group = item.Web.Groups[groupName];
                if (roleDefinition != null && group != null)
                    SetPermissions(item, (SPPrincipal)group, roleDefinition);
            }
        }
        public static void SetPermissions(SPListItem item, string groupName, SPRoleType roleType)
        {
            if (item != null)
            {
                SPRoleDefinition roleDefinition = item.Web.RoleDefinitions.GetByType(roleType);
                SPGroup group = item.Web.Groups[groupName];
                if (group != null)
                    SetPermissions(item, (SPPrincipal)group, roleDefinition);
            }
        }

        /// <summary>
        /// Set Permissions
        /// </summary>
        /// <param name="item">SPListItem</param>
        /// <param name="principals">IEnumerable</param>
        /// <param name="roleType">SPRoleType</param>
        public static void SetPermissions(SPListItem item, IEnumerable<SPPrincipal> principals, SPRoleType roleType)
        {
            if (item != null)
            {
                foreach (SPPrincipal principal in principals)
                {
                    SPRoleDefinition roleDefinition = item.Web.RoleDefinitions.GetByType(roleType);
                    SetPermissions(item, principal, roleDefinition);
                }
            }
        }

        /// <summary>
        /// Set Permissions
        /// </summary>
        /// <param name="item">SPListItem</param>
        /// <param name="principal">SPPrincipal</param>
        /// <param name="roleType">SPRoleType</param>
        public static void SetPermissions(SPListItem item, SPPrincipal principal, SPRoleType roleType)
        {
            if (item != null)
            {
                SPRoleDefinition roleDefinition = item.Web.RoleDefinitions.GetByType(roleType);
                SetPermissions(item, principal, roleDefinition);
            }
        }

        /// <summary>
        /// Set Permissions
        /// </summary>
        /// <param name="item">SPListItem</param>
        /// <param name="user">SPUser</param>
        /// <param name="roleDefinition">SPRoleDefinition</param>
        public static void SetPermissions(SPListItem item, SPUser user, SPRoleDefinition roleDefinition)
        {
            if (item != null)
            {
                SetPermissions(item, (SPPrincipal)user, roleDefinition);
            }
        }

        /// <summary>
        /// Set Permissions
        /// </summary>
        /// <param name="item">SPListItem</param>
        /// <param name="principal">SPPrincipal</param>
        /// <param name="roleDefinition">SPRoleDefinition</param>
        public static void SetPermissions(SPListItem item, SPPrincipal principal, SPRoleDefinition roleDefinition)
        {
            if (item != null)
            {
                BreakRoleSPListItem(item);
                SPRoleAssignment roleAssignment = new SPRoleAssignment(principal);
                roleAssignment.RoleDefinitionBindings.Add(roleDefinition);
                item.RoleAssignments.Add(roleAssignment);
            }
        }

        #endregion

        #region Deleting all user Permissions from an item

        /// <summary>
        /// remove permisions
        /// </summary>
        /// <param name="item">SPListItem</param>
        /// <param name="user">SPUser</param>
        public static void RemovePermissions(SPListItem item, SPUser user)
        {
            if (item != null)
            {
                RemovePermissions(item, user as SPPrincipal);
            }
        }

        public static void RemovePermissions(SPListItem item, string groupName)
        {
            if (item != null)
            {
                SPGroup group = item.Web.Groups[groupName];
                if (group != null)
                    RemovePermissions(item, group as SPPrincipal);
            }
        }

        /// <summary>
        /// remove permisions
        /// </summary>
        /// <param name="item">SPListItem</param>
        /// <param name="principal">SPPrincipal</param>
        public static void RemovePermissions(SPListItem item, SPPrincipal principal)
        {
            if (item != null)
            {
                BreakRoleSPListItem(item);
                item.RoleAssignments.Remove(principal);
                // item.SystemUpdate();
            }
        }

        #endregion

        #region Removing specific roles from an item

        /// <summary>
        /// remove permission
        /// </summary>
        /// <param name="item">SPListItem</param>
        /// <param name="principal">SPPrincipal</param>
        /// <param name="roleDefinition">SPRoleDefinition</param>
        public static void RemovePermissionsSpecificRole(SPListItem item, SPPrincipal principal, SPRoleDefinition roleDefinition)
        {
            if (item != null)
            {
                SPRoleAssignment roleAssignment = item.RoleAssignments.GetAssignmentByPrincipal(principal);
                if (roleAssignment != null)
                {
                    if (roleAssignment.RoleDefinitionBindings.Contains(roleDefinition))
                    {
                        roleAssignment.RoleDefinitionBindings.Remove(roleDefinition);
                        roleAssignment.Update();
                    }
                }
            }
        }

        /// <summary>
        /// remove permission
        /// </summary>
        /// <param name="item">SPListItem</param>
        /// <param name="principal">SPPrincipal</param>
        /// <param name="roleType">SPRoleType</param>
        public static void RemovePermissionsSpecificRole(SPListItem item, SPPrincipal principal, SPRoleType roleType)
        {
            if (item != null)
            {
                SPRoleDefinition roleDefinition = item.Web.RoleDefinitions.GetByType(roleType);
                RemovePermissionsSpecificRole(item, principal, roleDefinition);
            }
        }
        public static void RemovePermissionsSpecificRole(SPListItem item, SPUser user, string roleName)
        {
            if (item != null)
            {
                SPRoleDefinition roleDefinition = item.Web.RoleDefinitions[roleName];
                if (roleDefinition != null)
                    RemovePermissionsSpecificRole(item, user as SPPrincipal, roleDefinition);
            }
        }
        public static void RemovePermissionsSpecificRole(SPListItem item, string groupName, string roleName)
        {
            if (item != null)
            {
                SPRoleDefinition roleDefinition = item.Web.RoleDefinitions[roleName];
                SPGroup group = item.Web.Groups[groupName];
                if (group != null && roleDefinition != null)
                    RemovePermissionsSpecificRole(item, group as SPPrincipal, roleDefinition);
            }
        }
        #endregion

        #region Updating or Modifying Permissions on an item

        /// <summary>
        /// modify Permissions
        /// </summary>
        /// <param name="item">SPListItem</param>
        /// <param name="principal">SPPrincipal</param>
        /// <param name="roleType">SPRoleType</param>
        public static void ChangePermissions(SPListItem item, SPPrincipal principal, SPRoleType roleType)
        {
            if (item != null)
            {
                SPRoleDefinition roleDefinition = item.Web.RoleDefinitions.GetByType(roleType);
                ChangePermissions(item, principal, roleDefinition);
            }
        }
        public static void ChangePermissions(SPListItem item, SPUser user, string roleName)
        {
            if (item != null)
            {
                SPRoleDefinition roleDefinition = item.Web.RoleDefinitions[roleName];
                if (roleDefinition != null)
                    ChangePermissions(item, user as SPPrincipal, roleDefinition);
            }
        }

        public static void ChangePermissions(SPListItem item, string groupName, string roleName)
        {
            if (item != null)
            {
                SPRoleDefinition roleDefinition = item.Web.RoleDefinitions[roleName];
                SPGroup group = item.Web.Groups[groupName];
                if (roleDefinition != null)
                    ChangePermissions(item, group as SPPrincipal, roleDefinition);
            }
        }
        /// <summary>
        /// modify Permissions
        /// </summary>
        /// <param name="item">SPListItem</param>
        /// <param name="principal">SPPrincipal</param>
        /// <param name="roleDefinition">SPRoleDefinition</param>
        public static void ChangePermissions(SPListItem item, SPPrincipal principal, SPRoleDefinition roleDefinition)
        {
            //SPRoleAssignment roleAssignment = item.RoleAssignments.GetAssignmentByPrincipal(principal);

            //if (roleAssignment != null)
            //{
            //    roleAssignment.RoleDefinitionBindings.RemoveAll();
            //    roleAssignment.RoleDefinitionBindings.Add(roleDefinition);
            //    roleAssignment.Update();
            //}
            RemovePermissions(item, principal);
            SetPermissions(item, principal, roleDefinition);
        }

        #endregion

        public static void BreakRoleSPListItem(SPListItem item)
        {
            if (item.HasUniqueRoleAssignments)
            {
                item.ResetRoleInheritance();
            }
            item.BreakRoleInheritance(false);
        }

        public static SPUser GetSPUserFromSPListItemByFieldName(SPListItem spItem, string fieldName)
        {
            SPFieldUser field = spItem.Fields[fieldName] as SPFieldUser;
            if (field != null && spItem[fieldName] != null)
            {
                SPFieldUserValue fieldValue = field.GetFieldValue(spItem[fieldName].ToString()) as SPFieldUserValue;
                if (fieldValue != null)
                {
                    return fieldValue.User;
                }
            }
            return null;
        }
        class DisabledItemEventsScope : SPItemEventReceiver, IDisposable
        {
            public DisabledItemEventsScope()
            {
                this.EventFiringEnabled = false;
            }
            #region IDisposable Members
            public void Dispose()
            {
                this.EventFiringEnabled = true;
            }
            #endregion
        }
        public static void SaveListItem(SPListItem item)
        {
            using (DisabledItemEventsScope scope = new DisabledItemEventsScope())
            {
                item.SystemUpdate();
            }
        }
    }
}

http://blog.csdn.net/minglelui/article/details/6731824