LINQ to Entities does not recognize the method

Question

I m getting the following error when trying to do a linq query      LINQ to Entities does not recognize the method  Boolean   IsCharityMatching System String  System String   method  and this   method cannot be translated into a store expression    I ve read lots of previous questions where people get the same error  and if I understand this correctly it s because LINQ to Entities requires the whole linq query expression to be translated to a server query  and therefore you can t call an outside method in it  I haven t been able to convert my scenario into something that works yet  and my brain is starting to melt down  so I was hoping someone could point me in the right direction  We re using Entity Framework and the specification pattern  and I m new to both    Here s the code that uses the specification   ISpecification lt Charity gt  specification   new CharitySearchSpecification charityTitle  charityReference    charities   charitiesRepository Find specification  OrderBy p   gt  p RegisteredName  ToList      Here s the linq expression   public System Linq Expressions Expression lt Func lt Charity  bool gt  gt  IsSatisfied         return p   gt  p IsCharityMatching this charityName  this charityReference       Here s the IsCharityMatching method   public bool IsCharityMatching string name  string referenceNumber        bool exists   true       if   String IsNullOrEmpty name                 if   this registeredName ToLower   Contains name ToLower     amp  amp               this alias ToLower   Contains name ToLower     amp  amp              this charityId ToLower   Contains name ToLower                           exists   false                       if   String IsNullOrEmpty referenceNumber                 if   this charityReference ToLower   Contains referenceNumber ToLower                           exists   false                       return exists      Let me know if you need any more information   Many thanks   Annelie

User · Answer

If anyone is looking for a VB Net answer  as I was initially   here it is   Public Function IsSatisfied   As Expression Of Func Of Charity  String  String  Boolean    Return Function charity  name  referenceNumber   String IsNullOrWhiteSpace name  Or                                                          charity registeredName ToLower   Contains name ToLower    Or                                                          charity alias ToLower   Contains name ToLower    Or                                                          charity charityId ToLower   Contains name ToLower     And                                                      String IsNullOrEmpty referenceNumber  Or                                                      charity charityReference ToLower   Contains referenceNumber ToLower     End Function

User · Answer

As you ve figured out  Entity Framework can t actually run your C  code as part of its query  It has to be able to convert the query to an actual SQL statement  In order for that to work  you will have to restructure your query expression into an expression that Entity Framework can handle   public System Linq Expressions Expression lt Func lt Charity  bool gt  gt  IsSatisfied         string name   this charityName      string referenceNumber   this referenceNumber      return p   gt            string IsNullOrEmpty name                  p registeredName ToLower   Contains name ToLower                   p alias ToLower   Contains name ToLower                   p charityId ToLower   Contains name ToLower      amp  amp           string IsNullOrEmpty referenceNumber                 p charityReference ToLower   Contains referenceNumber ToLower

User · Answer

I got the same error in this code    var articulos en almacen   xx IV00102 Where iv   gt  alm x suc Exists axs   gt  axs almacen    iv LOCNCODE Trim     Select iv   gt  iv ITEMNMBR Trim    ToList      this was the exactly error      System NotSupportedException   LINQ to Entities does not recognize the method  Boolean Exists System Predicate 1 conector gp Models almacenes por sucursal    method  and this method cannot be translated into a store expression     I solved this way   var articulos en almacen   xx IV00102 ToList   Where iv   gt  alm x suc Exists axs   gt  axs almacen    iv LOCNCODE Trim     Select iv   gt  iv ITEMNMBR Trim    ToList      I added a  ToList   before my table  this decouple the Entity and linq code  and avoid my next linq expression be translated  NOTE  this solution isn t optimal  because avoid entity filtering  and simply loads all table into memory

[.net] LINQ to Entities does not recognize the method

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