public static void SetFilePermission(SPWeb web, SPDocumentLibrary lib, SPUser group)
{
//改变站点继承权
if (!web.HasUniqueRoleDefinitions)
{
// web.RoleDefinitions.BreakInheritance(false, false);//复制父站点角色定义并且保持权限
}
//站点继承权改变后重新设置状态
web.AllowUnsafeUpdates = true;
lib.BreakRoleInheritance(false, false);
SPRoleAssignment roleAssignment = new SPRoleAssignment(group);
SPRoleDefinition roleDefinition = web.RoleDefinitions.GetByType(SPRoleType.Reader);
roleAssignment.RoleDefinitionBindings.Add(roleDefinition);
lib.RoleAssignments.Add(roleAssignment);
}