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How to set dynamic column in linq query

I have following code,
public List<MemberDto> GetMembers(out int rowCount,int pageIndex,int pageSize, string seachBy = "", string searchTerm = "", string sortBy = "", string sortDiection = "")
{
var members = (from m in context.Members
where (string.IsNullOrEmpty(searchTerm) || m.MemberNumber.Equals(searchTerm))
|| (string.IsNullOrEmpty(searchTerm) || m.LastName.Equals(searchTerm))
select m).AsEnumerable();
if (!string.IsNullOrEmpty(sortBy))
{
PropertyDescriptor prop = TypeDescriptor.GetProperties(typeof(EFModel.ClientData.Member)).Find(sortBy, true);
members = (sortDiection.ToLower() == "descnding") ? members.OrderByDescending(x => prop.GetValue(x)).ToList() : members.OrderBy(x => prop.GetValue(x)).ToList();
}
rowCount = (!string.IsNullOrEmpty(searchTerm)) ? members.Count() : rowCount = context.Members.Count() ;
members = members.Skip(pageIndex).Take(pageSize).ToList();
List<MemberDto> memberDtos = new List<MemberDto>();
mapper.Map(members, memberDtos);
return memberDtos;
}
In the above method string seachColumn value can be memberno or lastname or sometime empty. when seachColumn value is memberno. I only need to search searchTerm value in MemberNumber column.
when seachColumn value is lastname. I only need to search searchTerm value in LastName column.
sometimes searchTerm can be empty. when it happen I need all the records without considering any search terms.
Above query is working bit. the problem is that when there is a value for searchTerm, That result is given regardless of the column. How can i do this.

public List<MemberDto> GetMembers(out int rowCount,int pageIndex,int pageSize, string seachColumn = "", string searchTerm = "", string sortBy = "", string sortDiection = "")
{
var query = context.Members;
if(string.IsNullOrWhitespace(searchTerm)
{
return query.ToList();
}
//if you want to check strings equality in ignore-case mode, you should change your db collation using the link below.
return query
.Where(m => m.MemberNumber.Equals(searchTerm) || m.LastName.Equals(searchTerm))
.ToList();
}
String equality check in ef using db collation

AsEnumerable Dynamic Fields in Where & Select

I want to use the distinct clause for multiple levels. Firstly i tried with DataTable but did't got success so i converted DataTable to AsEnumerable.
My problem here is that the Fields which i have specified/hard coded will be coming dynamic, same for both Where & Select.
How to add dynamic Fields in Where & Select?
DataTable data3 = new DataTable();
var listData = data3.AsEnumerable()
.Where(m => !String.IsNullOrEmpty(m.Field<string>("clientname"))
&& !String.IsNullOrEmpty(m.Field<string>("project"))
&& !String.IsNullOrEmpty(m.Field<string>("postedstate"))
&& !String.IsNullOrEmpty(m.Field<string>("postedcity"))
&& !String.IsNullOrEmpty(m.Field<string>("siteadd")))
.Select(row => new
{
clientname = row.Field<string>("clientname"),
project = row.Field<string>("project"),
postedstate = row.Field<string>("postedstate"),
postedcity = row.Field<string>("postedcity"),
siteadd = row.Field<string>("siteadd")
}).Distinct();

You could do something similar to this:
string clientName = "my client";
string project = null;
DataTable data3 = new DataTable();
var listData = data3.AsEnumerable().Where(m =>
(String.IsNullOrEmpty(clientName) || m.Field<string>("clientname") == clientName)
&& (String.IsNullOrEmpty(project) || m.Field<string>("project") == project)
).Select(row => new Project()
{
clientname = row.Field<string>("clientname"),
project = row.Field<string>("project"),
postedstate = row.Field<string>("postedstate"),
postedcity = row.Field<string>("postedcity"),
siteadd = row.Field<string>("siteadd")
}).Distinct();
This way you will have no need to have an anonymous type returned and get rid of the problem.

Linq to Sql - return all data if 'contains' value is null in where clause

I need to get all vendorname if value(data.vendorname) is null its give an error Exception: "Value cannot be null."
public HttpResponseMessage PostFilter([FromBody] dynamic data)
{
string[] vendorname = data.vendorname != null
? data.vendorname.ToObject<string[]>()
: null;
var items = (from s in context.AllInventories
where
(vendorname!=null
? vendorname.Contains(s.VENDORNAME)
:1==1)
select s)
.Take(500)
.ToList();
}

Why don't you simplify this, by just not applying any where at all if vendorname is null?
public HttpResponseMessage PostFilter([FromBody] dynamic data)
{
string[] vendorname = data.vendorname != null
? data.vendorname.ToObject<string[]>()
: null;
var query = context.AllInventories.AsQueryable();
if (vendorname != null)
{
query = query.Where(s => vendorname.Contains(s.VENDORNAME));
}
var items = query.Take(500).ToList();
}

Why don't you use a simple if-statement?
IEnumerable<Inventory> inventories = context.AllInventories;
if(vendorname != null)
inventories = inventories.Where(i => vendorname.Contains(i.VENDORNAME));
inventories = inventories.Take(500).ToList();
That's much better than hoping that your sql trick works and that the optimizer is clever enough to ignore your pseudo-condition. It's also better to debug.

How to use replace function in linq

I am trying to create a replace function, which can replace multiple strings within the 'body' fieldname of my linq queries.
This is my linq function:
public string GetReplacedText(string body)
{
var data = from c in db.StoryTbls
where c.Body == body
select new
{
c.Body
};
Regex rgx2 = new Regex("<P align=right><A href>RS</A></P>");
Regex rgx3 = new Regex("<A href>ML</A>");
string res = rgx2.Replace(body, "");
res = rgx3.Replace(body,"");
return res;
}
I am calling the above function, into the below 'httpresponse' method.
public HttpResponseMessage getData()
{
if (User.IsInRole("admin"))
{
Regex rgx2 = new Regex("<A href></A>");
var join = (from s in db.StoryTbls
join c in db.META_Cat on s.Theme equals c.metaIndex
where s.ACTIVE == true
&& s.PUB_ID == 250
&& c.Categories == "RM"
orderby s.ACTIVEDATE descending
select new
{
s.TITLE,
s.Body,
s.ACTIVEDATE,
c.Categories
}).AsEnumerable().Select(c => new NewObj
{
Title = c.TITLE,
Body = GetReplacedText(c.Body),
ActiveDate = c.ACTIVEDATE,
Categories = c.Categories
}).Take(50).ToList();
var data = join.ToList();
if (!data.Any())
{
var message = string.Format("No data found");
return Request.CreateErrorResponse(HttpStatusCode.NotFound, message);
}
However, when I call the API, the body content data is not replaced. Hence the function not working.
Please advise, as to where I may be going wrong.
Many thanks

You need to take the output from your first call to Replace and pass it in to your second call to Replace, like so:
string res = rgx2.Replace(body, "");
res = rgx3.Replace(res, "");

What can be used instead of Datatable in LINQ

I have a SQL query that returns a Datatable:
var routesTable = _dbhelper.Select("SELECT [RouteId],[UserId],[SourceName],[CreationTime] FROM [Routes] WHERE UserId=#UserId AND RouteId=#RouteId", inputParams);
and then we can work with Datatable object of routesTable
if (routesTable.Rows.Count == 1)
{
result = new Route(routeId)
{
Name = (string)routesTable.Rows[0]["SourceName"],
Time = routesTable.Rows[0]["CreationTime"] is DBNull ? new DateTime() : Convert.ToDateTime(routesTable.Rows[0]["CreationTime"])
};
result.TrackPoints = GetTrackPointsForRoute(routeId);
}
I want to change this code to linq but I don't know how can I simulate Datatable in LINQ ,I wrote this part:
Route result = null;
aspnetdbDataContext aspdb = new aspnetdbDataContext();
var Result = from r in aspdb.RouteLinqs
where r.UserId == userId && r.RouteId==routeId
select r;
....
but I don't know how can I change this part:
if (routesTable.Rows.Count == 1)
{
result = new Route(routeId)
{
Name = (string)routesTable.Rows[0]["SourceName"],
Time = routesTable.Rows[0]["CreationTime"] is DBNull ? new DateTime() : Convert.ToDateTime(routesTable.Rows[0]["CreationTime"])
};
would you please tell me how can I do this?
EDIT
here you can see the whole block of code in original
public Route GetById(int routeId, Guid userId)
{
Route result = null;
var inputParams = new Dictionary<string, object>
{
{"UserId", userId},
{"RouteId", routeId}
};
var routesTable = _dbhelper.Select("SELECT [RouteId],[UserId],[SourceName],[CreationTime] FROM [Routes] WHERE UserId=#UserId AND RouteId=#RouteId", inputParams);
if (routesTable.Rows.Count == 1)
{
result = new Route(routeId)
{
Name = (string)routesTable.Rows[0]["SourceName"],
Time = routesTable.Rows[0]["CreationTime"] is DBNull ? new DateTime() : Convert.ToDateTime(routesTable.Rows[0]["CreationTime"])
};
result.TrackPoints = GetTrackPointsForRoute(routeId);
}
return result;
}
SELECT Function:
public DataTable Select(string query, Dictionary<string, object> parameters)
{
var dt = new DataTable();
using (_command = new SqlCommand(query, _connnection))
{
InitializeParametersAndConnection(parameters);
using (_adapter = new SqlDataAdapter(_command))
{
_adapter.Fill(dt);
}
}
return dt;
}
and the GetTrackPointsForRoute
private List<TrackPoint> GetTrackPointsForRoute(int routeId)
{
aspnetdbDataContext aspdb = new aspnetdbDataContext();
var result = new List<TrackPoint>();
var trackPointsTable = from t in aspdb.TrackPointlinqs
where t.RouteFK == routeId
select t;
foreach (var trackPointRow in trackPointsTable)
{
var trackPoint = new TrackPoint
{
Id = (int)trackPointRow.TrackPointId,
Elevation = Convert.ToSingle(trackPointRow.Elevation),
Latitude = Convert.ToDouble(trackPointRow.Latitude),
Longitude = Convert.ToDouble(trackPointRow.Longitude),
Time = trackPointRow.TrackTime is DBNull ? new DateTime() : (DateTime)trackPointRow.TrackTime
};
result.Add(trackPoint);
}
return result;
}

var firstRoute = aspdb.RouteLinqs
.Where(r => r.UserId == userId && r.RouteId == routeId)
.FirstOrDefault();
if (firstRoute == null)
{
return null;
}
else
{
return new Route(routeId)
{
Name = first.SourceName,
Time = first.CreationTime ?? new DateTime(),
TrackPoints = GetTrackPointsForRoute(routeId)
};
}
If this is LINQ to SQL you can simplify it further (this won't work with LINQ to Entity Framework though):
return aspdb.RouteLinqs
.Where(r => r.UserId == userId && r.RouteId == routeId)
.Select(r => new Route(routeId)
{
Name = r.SourceName,
Time = r.CreationTime ?? new DateTime(),
TrackPoints = GetTrackPointsForRoute(routeId)
})
.FirstOrDefault();
Note: You probably can replace GetTrackPointsForRoute with a join to the child table, meaning that the entire method can be done with a single call to the database, rather than one call to get the routes, and a second call to get the points. To do this you should learn about associations and joins in LINQ to SQL.