Question

I have built a data driven model by dragging my tables onto the empty designer of an edml. I know that I can establish a datacontext around my model, and that I can access each table as though it were a class, but where is the code for each of these models?

I ask because I want to add validation to the setters of each property on the class itself.

Answer 1

Look for a .dbml file on the root level of your project. Under that file, you will see a file called <someDB>.designer.cs.

However, (and you’ll see this at the top of the designer file as well), you don’t really want to make any changes to the classes in this file.

//     Changes to this file may cause incorrect behavior and will be lost if
//     the code is regenerated.

If you want to make additions, you should look into creating Partial classes that extend the functionality of the generated classes.

Here is a sample partial class that I created to handle my validations:

 namespace ETL_Framework_UI
{
[MetadataType(typeof(DataObjectMD))]
public partial class DATA_OBJECT:IValidatableObject
{

    public class DataObjectMD
    {
        [Required(ErrorMessage="The object name is required")]
        [StringLength(50, ErrorMessage = "Name cannot exceed 50 characters")]
        public string OBJECT_NAME { get; set; }

    }
    public IEnumerable<ValidationResult> Validate(ValidationContext validationContext)
    {
        ETLDbDataContext db = new ETLDbDataContext();
        var field = new[] { "OBJECT_NAME" };
        var param = db.DATA_OBJECTs.SingleOrDefault(r => r.OBJECT_NAME == OBJECT_NAME && r.OBJECT_ID != OBJECT_ID);
        if (param != null)
        {
            yield return new ValidationResult("Object name is already in use. ", field);
}

NOTE Your partial class must be defined in the same namespace that you see at the top of your designer.cs file.