Why doesn't the search for ASP MVC JSON?

[zymir]

There's a controller, that's the type that sends JSON.

[HttpPost]
        public ActionResult LoadDataFromAD()
        {
        //Get parameters
        var v = ActiveDirectory.GetUserFromAD();
        // get Start (paging start index) and length (page size for paging)
        var draw = Request.Form.GetValues("draw").FirstOrDefault();
        var start = Request.Form.GetValues("start").FirstOrDefault();
        var length = Request.Form.GetValues("length").FirstOrDefault();
        //Get Sort columns value
        var sortColumn = Request.Form.GetValues("columns[" + Request.Form.GetValues("order[0][column]").FirstOrDefault() + "][name]").FirstOrDefault();
        var sortColumnDir = Request.Form.GetValues("order[0][dir]").FirstOrDefault();

        //find search columns info
        var contactName = Request.Form.GetValues("columns[0][search][value]").FirstOrDefault();


        //SEARCHING...
        if (!string.IsNullOrEmpty(contactName))
        {
            v = v.Where(a => a.DisplayName.Contains(contactName));
        }


        int pageSize = length != null ? Convert.ToInt32(length) : 0;
        int skip = start != null ? Convert.ToInt32(start) : 0;
        int totalRecords = 0;


        totalRecords = v.Count();

        var data = v.Skip(skip).Take(pageSize).ToList();
        return Json(new { draw = draw, recordsFiltered = totalRecords, recordsTotal = totalRecords, data = data }, JsonRequestBehavior.AllowGet);
    }

Data are correctly transmitted to AC contactName.

//SEARCHING...

if (!string.IsNullOrEmpty(contactName))

{

v = v.Where(a => a.DisplayName.Contains(contactName));

}

The error arises when searching

I don't know when I write Contains like that.

 v = v.Where(a => a.DisplayName==contactName);

And I'm putting in a full line to search the table, everything works on the corner. Help!

[chanisef]

Structural variables may be important null♪ Add the check:

a.DisplayName != null && aDisplayName.Contains(...