ExecuteStoreCommand returns -1 , EntityFramework , C#?

问题

I wanna get the next automatically incrementing primary key, Here I understood to use T-SQL for doing that. So I wrote the following method :

public int GetLastNewsID()
{
    const string command = @"SELECT IDENT_CURRENT ('{0}') AS Current_Identity;";
    int id = EntityModel.ExecuteStoreCommand(command, "News");
    return id;
}

but it returns -1, whereas it must be 4 right now.

P.S: When I execute below T-SQL in SQL Management Studio , it returns 4

USE T;
GO
SELECT IDENT_CURRENT ('NEWS') AS Current_Identity;
GO

回答1:

You need to use ExecuteStoreQuery

public int GetLastNewsID()
{
    const string command = @"SELECT IDENT_CURRENT ({0}) AS Current_Identity;";
    var id = EntityModel.ExecuteStoreQuery<decimal>(command, "News").First();

    return Convert.ToInt32(id);
}

The SQL query will return a decimal so you need to convert it to int.

回答2:

Read part about return value:

http://msdn.microsoft.com/en-us/library/system.data.objects.objectcontext.executestorecommand.aspx

来源：https://stackoverflow.com/questions/7750587/executestorecommand-returns-1-entityframework-c