Dynamic Search Using Entity Framework - entity-framework

Question

I have a search screen with optional fields using Entity Framework, I want to build a dynamic query without selecting the object and filter on it.
I want to Optimize the following Existing Search, I don't want to select "var query = from p in context.APLCN_TRCKR select p;" at this stage because the application will be used by more than 100 people at once:
using (var context = new VASTEntities())
{
var query = from p in context.APLCN_TRCKR select p;
if (!string.IsNullOrEmpty(searchObj.CUST_NAME_X))
query = query.Where(p => p.CUST_NAME_X == searchObj.CUST_NAME_X.Trim());
if (!string.IsNullOrEmpty(searchObj.SURNM_X))
query = query.Where(p => p.CUST_SURNM_X == searchObj.SURNM_X.Trim());
if (!string.IsNullOrEmpty(searchObj.QUEUE_ID))
query = query.Where(p => p.QUEUE_ID == searchObj.QUEUE_ID.Trim());
if (!string.IsNullOrEmpty(searchObj.BP_ID))
query = query.Where(p => p.BPID == searchObj.BP_ID.Trim());
if (!string.IsNullOrEmpty(searchObj.UserID))
query = query.Where(p => p.CURR_OWNR_USER_ID == searchObj.UserID.Trim());
if (!string.IsNullOrEmpty(searchObj.APLCN_TRCKR_ID))
query = query.Where(p => p.APLCN_TRCKR_ID == searchObj.APLCN_TRCKR_ID.Trim());
if (!string.IsNullOrEmpty(searchObj.APLCN_STTS_ID))
query = query.Where(p => p.APLCN_STTS_ID == searchObj.APLCN_STTS_ID.Trim());
if (!string.IsNullOrEmpty(searchObj.CUST_ID))
query = query.Where(p => p.CUST_ID == searchObj.CUST_ID.Trim());
if (!string.IsNullOrEmpty(searchObj.CELL_ID))
query = query.Where(p => p.CELL_ID == searchObj.CELL_ID.Trim());
if (!string.IsNullOrEmpty(searchObj.ORIGN_ID))
query = query.Where(p => p.ORIGN_ID == searchObj.ORIGN_ID.Trim());
if (!string.IsNullOrEmpty(searchObj.ORGTN_CHANL_ID))
query = query.Where(p => p.ORGTN_CHANL_ID == searchObj.ORGTN_CHANL_ID.Trim());
if (!string.IsNullOrEmpty(searchObj.CR_DCSN_ID))
query = query.Where(p => p.CR_DCSN_ID == searchObj.CR_DCSN_ID.Trim());
if (!string.IsNullOrEmpty(searchObj.SBSA_CUST_I))
query = query.Where(p => p.SBSA_CUST_I == searchObj.SBSA_CUST_I.Trim());
if (!string.IsNullOrEmpty(searchObj.USER_ID_APP_CRTD))
query = query.Where(p => p.USER_ID_APP_CRTD == searchObj.USER_ID_APP_CRTD.Trim());
if (!string.IsNullOrEmpty(searchObj.RGION_ID))
{
int r = int.Parse(searchObj.RGION_ID.Trim());
query = query.Where(p => p.RGION_ID == r);
}
if (!string.IsNullOrEmpty(searchObj.CR_REGION))
{
int x = int.Parse(searchObj.CR_REGION);
if (x == 0)
{
// check 0 - not applicable or null
query = query.Where(p => p.CR_REGION_ID == 0 || p.CR_REGION_ID == null);
}
else
{
query = query.Where(p => p.CR_REGION_ID == x);
}
}
if (!string.IsNullOrEmpty(searchObj.Process_Type))
query = query.Where(p => p.PRCES_TYPE_ID == searchObj.Process_Type.Trim());
query.ToList();
foreach (var a in query)
{
searchAppsObj.Add(Translator.TranslateReqObjToBO.TranslateDTOToSearchApp(a));
}
if (query.Count() == 0)
{
throw new Exception("No Applications Found.");
}
context.Connection.Close();
return searchAppsObj;
}
I want to do something like this but this one is not working properly:
string cust_name_x = "", surname_x = "", queue_id = "", bp_id = "", user_id = "", aplcn_trckr_id = "",
aplcn_stts_id = "", cust_id = "", process_type = "", cr_region = "", cell_id = "", Origin = "", region = "", channel = "", credit_verdict = "", sbsa_cust_id = "", app_creator_id = "";
if (!string.IsNullOrEmpty(searchObj.CUST_NAME_X))
cust_name_x = searchObj.CUST_NAME_X.Trim();
if (!string.IsNullOrEmpty(searchObj.SURNM_X))
surname_x = searchObj.SURNM_X.Trim();
if (!string.IsNullOrEmpty(searchObj.QUEUE_ID))
queue_id = searchObj.QUEUE_ID.Trim();
if (!string.IsNullOrEmpty(searchObj.BP_ID))
bp_id = searchObj.BP_ID;
if (!string.IsNullOrEmpty(searchObj.UserID))
user_id = searchObj.UserID.Trim();
if (!string.IsNullOrEmpty(searchObj.APLCN_TRCKR_ID))
aplcn_trckr_id = searchObj.APLCN_TRCKR_ID.Trim();
if (!string.IsNullOrEmpty(searchObj.APLCN_STTS_ID))
aplcn_stts_id = searchObj.APLCN_STTS_ID.Trim();
if (!string.IsNullOrEmpty(searchObj.CUST_ID))
cust_id = searchObj.CUST_ID.Trim();
if (!string.IsNullOrEmpty(searchObj.Process_Type))
process_type = searchObj.Process_Type.Trim();
if (!string.IsNullOrEmpty(searchObj.CR_REGION))
cr_region = searchObj.CR_REGION.Trim();
if (!string.IsNullOrEmpty(searchObj.CELL_ID))
cell_id = searchObj.CELL_ID.Trim();
if (!string.IsNullOrEmpty(searchObj.ORIGN_ID))
Origin = searchObj.ORIGN_ID.Trim();
if (!string.IsNullOrEmpty(searchObj.RGION_ID))
region = searchObj.RGION_ID.Trim();
if (!string.IsNullOrEmpty(searchObj.ORGTN_CHANL_ID))
channel = searchObj.ORGTN_CHANL_ID.Trim();
if (!string.IsNullOrEmpty(searchObj.CR_DCSN_ID))
credit_verdict = searchObj.CR_DCSN_ID.Trim();
if (!string.IsNullOrEmpty(searchObj.SBSA_CUST_I))
sbsa_cust_id = searchObj.SBSA_CUST_I.Trim();
if (!string.IsNullOrEmpty(searchObj.USER_ID_APP_CRTD))
app_creator_id = searchObj.USER_ID_APP_CRTD.Trim();
using (var context = new VASTEntities())
{
var query = from p in context.APLCN_TRCKR
where
p.CUST_NAME_X.Contains(cust_name_x) &&
p.CUST_SURNM_X.Contains(surname_x) &&
p.QUEUE_ID.Contains(queue_id) &&
p.BPID.Contains(bp_id) &&
p.CURR_OWNR_USER_ID.Contains(user_id) &&
p.APLCN_TRCKR_ID.Contains(aplcn_trckr_id) &&
p.APLCN_STTS_ID.Contains(aplcn_stts_id) &&
p.CUST_ID.Contains(cust_id) &&
p.PRCES_TYPE_ID.Contains(process_type) &&
p.CELL_ID.Contains(cell_id) &&
SqlFunctions.StringConvert((double)p.CR_REGION_ID).Contains(cr_region) &&
p.ORIGN_ID.Contains(Origin) &&
SqlFunctions.StringConvert((double)p.RGION_ID).Contains(region) &&
p.ORGTN_CHANL_ID.Contains(channel) &&
p.CR_DCSN_ID.Contains(credit_verdict) &&
p.SBSA_CUST_I.Contains(sbsa_cust_id)
select p;
query.ToList();
if (query.Count() == 0)
{
throw new Exception("No Applications Found.");
}
foreach (var a in query)
{
searchAppsObj.Add(Translator.TranslateReqObjToBO.TranslateDTOToSearchApp(a));
}
context.Connection.Close();
return searchAppsObj;
}

Answer 1

You can just create a collection of lambda expression like below:
var filters = new List<Expression<Func<Application, bool>>>();
if (!string.IsNullOrWhitespace(searchObj.CUST_NAME_X))
filters.Add(application => application .CUST_NAME_X.Contains(searchObj.CUST_NAME_X.Trim());
if (!string.IsNullOrEmpty(searchObj.SURNM_X))
filters.Add(application => application .CUST_SURNM_X.Contains(searchObj.SURNM_X.Trim());
// And so on for all criteria
After that you can do a loop on filters like below:
using (var context = new VASTEntities())
{
var query = context.APLCN_TRCKR;
foreach(var filter in filters)
{
query = query.Where(filter);
}
var result = query.ToList();
if (result.Count() == 0)
{
throw new Exception("No Applications Found.");
}
foreach (var a in result)
{
searchAppsObj.Add(Translator.TranslateReqObjToBO.TranslateDTOToSearchApp(a));
}
context.Connection.Close();
return searchAppsObj;
}

Answer 2

change
var query = from p in context.APLCN_TRCKR select p;
to
var query = context.APLCN_TRCKR.AsQueryable();
And when the filtering work is done:
await query.ToListAsync() // this one goes to the database
Also have a look at this: Linq query filtering
In Addition: don't call context.Connection.Close(); as this is going to be executed anyway because using behaves like try { ... } finally { // dispose work }