Question

Given a table or view with an Integer column is it possible to do a conversion or cast to a String value in the DBML or create a calculated property on the entity that can be used as a relationship to another entity?

I have tried making the generated type a string but it gives an error:
Error 1 DBML1005: Mapping between DbType ‘Int’ and Type ‘System.String’ in Column ‘Foo’ of Type ‘FooRecord’ is not supported. 0 0

Answer 1

I don’t think you can do anything like this – not in the Linq-to-SQL data model, for sure. If it’s an INT in the database, it’s an INT in the model and cannot be “manipulated” into being a string all of a sudden…

But what you could do is extend that class that Linq-to-SQL generates for you – it’s a partial class, e.g. you can extend it in a separate, second file:

YourEntityEx.cs

public partial class YourEntity
{
   public string YourPropertyAsString
   {
      get { return YourProperty.ToString(); }
      set { YourProperty = Convert.ToInt32(value); }  // if you even this
   }
}

This way, you now have a second property YourPropertyAsString on your YourEntity class that will always be exactly the same as YourProperty – only of type string.