Hi AjayP,
You should apply where condition like below.
var strQuery = from customer in cde.Customers
select customer;
if (!string.IsNullOrEmpty(strMobNo))
{
strQuery = strQuery.Where(x => x.CustMobNo == strMobNo);
}
if (!string.IsNullOrEmpty(strName))
{
strQuery = strQuery.Where(x => x.CustName == strName);
}
if (!string.IsNullOrEmpty(strCity))
{
strQuery = strQuery.Where(x => x.CustCity == strCity);
}