Problem with LINQ to Entities and String.StartsWith

Question

I'm trying to build a search page using LINQ to Entities, but the following code is giving me a runtime error about l.t.e. not recognising 'Boolean StartsWith(). The code compiles just fine. How can I work around this better than shipping the StartsWith filtering out to a stored proc?

    return from dp in dents.DirectoryPersonEntrySet
           where
               ((dp.LastName.StartsWith(searchTerm, StringComparison.CurrentCultureIgnoreCase)) ||
                (dp.Department.StartsWith(searchTerm, StringComparison.CurrentCultureIgnoreCase)) ||
                dp.Extension.StartsWith(searchTerm, StringComparison.CurrentCultureIgnoreCase))
           select dp;

Could you post the 'following code'? Or is the subject the complete code? You mean String.StartsWith instead of Boolean.StartsWith? — Rutger Nijlunsing, Jun 13 '09 at 10:16
@Rutger, thanks, I was too quick to hit send and forgot the code. I also fixed the signature. — ProfK, Jun 13 '09 at 10:41
There're at least 6 parentheses in excess, and we're still missing the function prototype and the class definition... — em70, Jun 13 '09 at 10:44
Try using StartsWith overload without StringComparison.CurrentCultureIgnoreCase. — Rinat Abdullin, Jun 13 '09 at 11:14
I have not used LINQ to Entities so I don't know whether it supports wildcards, but can't you use "like" plus a wild card? — flipdoubt, Jun 13 '09 at 11:36
@emaster: What function prototype or class definition would you like? Everything relevant to my question is present, and the surplus parentheses have no bearing on the issue. — ProfK, Jun 15 '09 at 09:59
Related posts - [LINQ to Entities does not recognize the method](https://stackoverflow.com/q/7259567/465053) & [Entity Framework Specification Pattern Implementation](https://stackoverflow.com/q/2352764/465053) — RBT, Mar 01 '19 at 11:27
Another related post - [LINQ to Entities does not recognize the method 'System.String ToString()' method, and this method cannot be translated into a store expression](https://stackoverflow.com/q/5899683/465053) — RBT, Mar 01 '19 at 11:29

score 107 · Accepted Answer · edited Nov 07 '14 at 13:37

107

I would guess that EF doesn't support the overload of StartsWith that takes a StringComparison parameter.

It should support StartsWith, EndsWith and Contains, so maybe you can try:

dp.LastName.StartsWith(searchTerm)

or:

dp.LastName.ToLower().StartsWith(searchTerm)

and then make sure that searchTerm is also lowercase.

edited Nov 07 '14 at 13:37

Vincent

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answered Jun 13 '09 at 10:46

BengtBe

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Guessed correctly, but mind that it is case insensitive when translated to SQL. – marsze Mar 31 '16 at 14:25
7

MAY be (is probably) case insensitive. It depends on the database collation settings – Roger Willcocks Jun 29 '16 at 22:33
2

It translates it to a LIKE statement with 'my string%', '%my string' and '%my string%' respectively, which is case-insensitive automatically and no way to specify it to be case-sensitive via this call – James Gray Jan 09 '17 at 18:39
life saver. I spent an hour to investigate it and didn't notice that I have used the overload method. +1 – Adeel Shekhani Oct 28 '18 at 17:02
If you are using SQLite these three methods dont work everytime as expected... – Flimtix Oct 27 '21 at 10:57
That solution did not work for me in .Net 4.7.2. I think it's a bug. – Michael W. Aug 30 '22 at 08:52

Problem with LINQ to Entities and String.StartsWith

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