To remind me
This post contains a custom LINQ database query that will includes conditions if there are exist variables and ignores conditions on empty variables.
Following is an example in one method:
/* returning json value
* with three conditions : vesselId, portCode, filterYear
*/
public JsonResult GetEvents(Decimal? vesselId, string portCode, string filterYear)
{
using (dbEntities dc = new dbEntities()) //define entities
{
var events = new List(); //define variable on searching table
if(vesselId == 0) { vesselId = null; } //state variable condition to null value
if (portCode.Equals("0")) { portCode = null; }//state variable condition to null value
var qry = from sched in dc.TABLE select sched; //starting query
if (vesselId != null) //state first condition if not null
{
qry = qry.Where(n => n.VSL_ID== vesselId);
}
if ( !String.IsNullOrEmpty(portCode))//state second condition if not null
{
qry = qry.Where(n => n.PORT.Equals(portCode));
}
if (!String.IsNullOrEmpty(filterYear))//state third condition if not null
{
qry = qry.Where(n => n.YEAR.Equals(filterYear));
}
events = qry.ToList();
return new JsonResult { Data = events, JsonRequestBehavior = JsonRequestBehavior.AllowGet }; // returning as json value
}
}
That's it,,
