CODEWITHSUNDEEP
c#entity-frameworklinq
Belterius
Belterius

Reputation: 758

Entity System.NotSupportedException when querying with FirstOrDefault

I'm trying to retrieve a unique element if it exist, or null if it doesn't.

my function is :

private Dealer GetOrCreateDealer(DataRow dataRow)
{
        ModelCamwareContext localContext = new ModelCamwareContext();
        string test = dataRow["Dealer"].ToString();
        Dealer dealer = localContext.Dealers.Where(x => x.Name == dataRow["Dealer"].ToString()).FirstOrDefault();
        if (dealer != null)
        {
         ...
        }
        else
        {
         ...
        }
}

my test string is just here to make sure I had no problem with the dataRow info, it works as expected and gives me the string on which I want to select my dealer.

Unless I am mistaken, FirstOrDefault should not give me any exception in case there is no dealer to retrieve, I should in that case have dealer = null.

The exception I get:

A first chance exception of type 'System.NotSupportedException' occurred in EntityFramework.dll
A first chance exception of type 'System.NotSupportedException' occurred in EntityFramework.dll
A first chance exception of type 'System.NotSupportedException' occurred in EntityFramework.SqlServer.dll

What did I miss ?

Upvotes: 0

Views: 971

Answers (1)

llouk
llouk

Reputation: 513

Entity cannot evaluate datatables values inside it's LINQ. Try something like this:

    ModelCamwareContext localContext = new ModelCamwareContext();
    string test = dataRow["Dealer"].ToString();
    Dealer dealer = localContext.Dealers.Where(x => x.Name == test).FirstOrDefault();
    if (dealer != null)
    {

    }
    else
    {

    }

Upvotes: 1

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