Finding a property is Primary Key in POCO Template t4 generator

Question

I'm using the POCO t4 template generator that comes with VS 2012. I made few changes to include the Entity.Name, but I'm not able to figure out the primary key.

public string EntityClassOpening(EntityType entity)
{
    return string.Format(
        CultureInfo.InvariantCulture,
        "{0} {1}partial class {2}{3}<{4},{5}>{6}",
        Accessibility.ForType(entity),
        _code.SpaceAfter(_code.AbstractOption(entity)),
        _code.Escape(entity),
        ": EntityBase",
        entity.Name,
        entity.Name,
        _code.StringBefore(" ", _typeMapper.GetTypeName(entity.BaseType)));
}

I don't find a way to find the primary key from the EntityType object hierarchy. It exposes properties but the property does not have anything to say it is a primary key.

Any help appreciated.

Flagship

Answer 1

Just in case anyone is trying to do this while migrating RIA services stuff, I'm using the standard dbcontext template in VS2013 and have added two things to the entities template.

first you need:

using System.ComponentModel.DataAnnotations;

I put it just under the //---- block near the top.

Then I modified the bit of code that looks like this. Just search for the first name. My change is ef.IsKey... and adding the Key() attribute.

    var simpleProperties = typeMapper.GetSimpleProperties(entity);
    if (simpleProperties.Any())
    {
        foreach (var edmProperty in simpleProperties)
        {
#>
 <#if (ef.IsKey(edmProperty))
   {#>      [Key()]
   <#}#>
    <#=codeStringGenerator.Property(edmProperty)#>
<#
        }
    }

Lydialydian

I'm finding that on a table which has no keys defined, the template is returning true for IsKey on multiple columns (not all). I need to have a look at what's going on there, but does anyone have any insight? – Nimrod

I think isKey checks for relationships in the edm file. They may not be what you're thinking of as a key column – Kassandrakassaraba

Answer 2

Use EntityType.KeyMembers property to get properties the primary key consists of.

Freezing

This helped. I ended up using EntityType.KeyProperties for my usage. Thanks! – Linkwork

@Linkwork could you please share your code you did using EntityType.KeyProperties? Thanks! – Handsel

Answer 3

I added this to the TypeMapper section, delighted with the results:

public IEnumerable<EdmProperty> GetPrimaryKeyProperties(EntityType type)
{
    return type.KeyMembers.Select(s => (EdmProperty)s);
}

Dahomey