Question

The entity framework connects to my database to retrieve columns, datatypes, relations, etc. It also knows which columns can be null and not null.

If I connect a regular asp.net grid to an entity datasource, it can generate the grid automatically based on the entity. It knows which fields should be a checkbox based on the datatype, etc.

Since data types are built into the entity class, can a regular asp.net control (like a grid or formview) also perform validation automatically? (or generate the necessary validation controls at least?)

Thanks,
Kevin

Answer 1

Yes, you can display validation errors including validation types using asp:ValidationSummary control. Here one project with this approach used on gridview: http://code.msdn.microsoft.com/ASPNET-Web-Forms-97f8ee9a , check out editing students.
The way to add more validation rules to entities is by attaching meta data.
If you are using EF Code First you can apply rules directly else by adding meta data class, here example:

[MetadataType(typeof(EntityNameMetaData))]
public partial class EntityName {} // name of entity which want to add validation
public class EntityNameMetaData // this is a place, where put validation rules
{
    [StringLength(25, ErrorMessage = "First name must be 25 characters or less in length.")]
    [Required(ErrorMessage = "First name is required.")]]
     //custom or other validation rules
     public String EntityProperty

}