Create Custom Permission level using Client Object model

ClientContext ctx = new ClientContext(“SPSiteurl”);

//create a new base permission

BasePermissions perms = new BasePermissions();

var _basePerm = | SPBasePermissions.AddListItems| SPBasePermissions.EditListItems;

perms.Set((PermissionKind)Enum.Parse(typeof(PermissionKind), _basePerm));

//create the construct for a new role definition

RoleDefinitionCreationInformation rdInfo = new RoleDefinitionCreationInformation();

//set the perms

rdInfo.BasePermissions = perms;

//set a descriptionrdInfo.Description = “Custom Role definition created with the client object
model”;

//set the name

rdInfo.Name = “My custom Permission level”;

//add the definition to the web collection

RoleDefinition rd = ctx.Web.RoleDefinitions.Add(rdInfo);

//execute to create

ctx.ExecuteQuery();

Now Assign a user this custom role definition –

/get the group

RoleDefinition rd = ctx.Web.RoleDefinitions.GetByName(“My custom Permission level”);

//get the user object

Principal usr = ctx.Web.EnsureUser(“domain\isha”);

//create the role definition binding collection

RoleDefinitionBindingCollection rdb = new RoleDefinitionBindingCollection(ctx);

//add the role definition to the collection

rdb.Add(rd);

//create a RoleAssigment with the user and role definition

ctx.Web.RoleAssignments.Add(usr, rdb);