Dynamic string in linq c#

Question

I have installed System.Linq.Dynamic dll and then tried to add string as the parameter of WHERE clause in Linq. But I am still getting error that the string parameter is supported by WHERE clause.

Code:

_dbContext.TmRecords.Where("city=london");

Error:

Severity Code Description Project File Line Error CS1503 Argument 2: cannot convert from 'string' to 'System.Linq.Expressions.Expression>' Extranet.Domain

Here the city parameter dynamically changes to some other parameter. So, I need to use dynamic queries in linq.

You need to create a predicate, such as: _dbContext.TmRecords.Where(record => record.city = "london"); — Markiian Benovskyi
– Markiian Benovskyi, Commented Oct 20, 2016 at 9:53
My first guess in such cases would be that you forgot the correct using — Kilazur
– Kilazur, Commented Oct 20, 2016 at 9:55
Do you have using System.Linq.Dynamic; at the top of your file? Without that, the only method that the compiler can find is the one expecting an expression and not a string. — DavidG
– DavidG, Commented Oct 20, 2016 at 9:57

Hamid Pourjam · Accepted Answer · 2016-10-20 09:59:14Z

7

You should add using System.Linq.Dynamic; to your file.

Also rewrite the query like this:

_dbContext.TmRecords.Where("city = @0", "london");

answered Oct 20, 2016 at 9:59

Hamid Pourjam

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4 Comments

Roy123 Over a year ago

using the @0 is necessary or just good practice? Thanks, this helped me aswell :)

Dinesh Over a year ago

The same thing how can i use it in lamda expression?

Hamid Pourjam Over a year ago

It is not necessary. You can use "City == \"london\"" instead but using parameterized one is more readable IMHO. @Roy_Dorsthorst

Hamid Pourjam Over a year ago

If you have another question then ask it in new question. @dineshsns

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