How would I get the column names from a Model LINQ?

Question

I am looking to get a list of the column names returned from a Model. Anyone know how this would be done, any help would be greatly appreciated.

Example Code:

var project = db.Projects.Single(p => p.ProjectID.Equals(Id));

This code would return the Projects object, how would I get a list of all the column names in this Model.

Thanks

Answer 1

Your columns should be mapped as properties on your Project model. I'm not sure if you can get the underlying database structure when using LINQ to SQL. The entire point of LINQ to SQL is to abstract the database away.

Answer 2

Your Projects wrapper will have a set of properties each with a [Column] attribute. So just use reflection to enumerate the properties with that attribute.

Answer 3

I am sorry, I don't have working experience with LINQ.

This is purely based on looking at MSDN.

DataContext has Mapping property (which gives instance of MetaModel)
MetaModel has GetMetaType (which takes a type. in your case it could be typeof(Project))
MetaType has GetDataMmber (which takes a MemberInfo. you will have to use reflection)
MetaDataMember instance should have all the things, you need.

I hope I am somewhat in right direction (purely looking at MSDN & traversing)

Answer 4

Thanks guys, you got me started on the right track. I found my solution with the following code. I can then iterate through the DataMembers and pull out their individual properties such as name, type, etc.

var db = new GMPDataContext();
var columnNames = db.Mapping.MappingSource
                    .GetModel(typeof(GMPDataContext))
                    .GetMetaType(typeof(Project))
                    .DataMembers;

Answer 5

This would be nice to have as an extension method:

public static class LinqExtensions
{
  public static ReadOnlyCollection<MetaDataMember> ColumnNames<TEntity> (this DataContext source)
  {
      return source.Mapping.MappingSource.GetModel (typeof (DataContext)).GetMetaType (typeof (TEntity)).DataMembers;
  }
}

example:

var columnNames = myDataContext.ColumnNames<Orders> ();