Ok... I give up... I've been searching this forum and staring at the docs and code for a couple of hours now trying to figure this out.

In Template Studio, using the C# templates, how can I get the name of the related field from a given EntityRelation.

<%  
foreach(EntityRelation rel in Entity.Relations)
{
    if(rel.RelationType == EntityRelationType.OneToMany && !rel.UtilizingPropertyIsHidden)
    {
        if (Entity.PrimaryKeyFields.Count == 1) {
            string primaryKeyName = ((EntityFieldDefinition)Entity.PrimaryKeyFields[0]).FieldName;
            string foreignKeyName = ((EntityFieldDefinition)Entity.PrimaryKeyFields[0]).MappedField.FieldName;
%>

in the above code: primaryKeyName and foreignKeyName are always the same... (the PK) Am I missing something?

I need to name of the FK field in the related table...

string fieldName = ((IDBField)((EntityFieldDefinition)Entity.PrimaryKeyFields[0]).MappedField).FieldName;

MappedField is a 'IEntityFieldMapTargetElement', which derives from IDBField. IDBField contains a property FieldName

Otis wrote:

string fieldName = ((IDBField)((EntityFieldDefinition)Entity.PrimaryKeyFields[0]).MappedField).FieldName;

MappedField is a 'IEntityFieldMapTargetElement', which derives from IDBField. IDBField contains a property FieldName

yes that's what I had:

 string foreignKeyName = ((EntityFieldDefinition)Entity.PrimaryKeyFields[0]).MappedField.FieldName;

But the resulting value in foreignKeyName was always the same as primaryKeyName in the code above...

The primary key should have been "FolderUID" and the foreign key field should have been "ChildFolderUID" (as defined in LLBLGen Designer)... But both are "FolderUID".

Doooooh!!!

Been looking at this for too long... I didn't even notice your code was different to mine!

But same problem ... I'm not sure that IDBField cast is required.

Ohhh!! I misunderstood you, I thought you couldn't retrieve the name from the field!.

I'll try to rewrite the code you're trying to achieve. (you're now grabbing the PK field, which obviously isn't correct, if you wnt to read the FK field)

Otis wrote:

Ohhh!! I misunderstood you, I thought you couldn't retrieve the name from the field!.

I'll try to rewrite the code you're trying to achieve. (you're now grabbing the PK field, which obviously isn't correct, if you wnt to read the FK field)

Thanks... I couldn't see anything in the EntityRelation that would help me either. I'm sure its something simple.

Marcus wrote:

Otis wrote:

Ohhh!! I misunderstood you, I thought you couldn't retrieve the name from the field!.

I'll try to rewrite the code you're trying to achieve. (you're now grabbing the PK field, which obviously isn't correct, if you wnt to read the FK field)

Thanks... I couldn't see anything in the EntityRelation that would help me either. I'm sure its something simple.

Yes, you have to use the EntityRelation.FieldRelations collection. That collection contains EntityFieldRelation objects: one per PK field (with its corresponding FK field).

So your code should be something like:

foreach(EntityRelation rel in Entity.Relations)
{
    if(rel.RelationType == EntityRelationType.OneToMany && !rel.UtilizingPropertyIsHidden)
    {
        if (Entity.PrimaryKeyFields.Count == 1) {
            // 1:n, so start entity is PK side.
            string primaryKeyName = rel.FieldRelations[0].RelationStartField.FieldName;
            string foreignKeyName = rel.FIeldRelations[0].RelationEndField.FieldName;

That's it... thanks!

The SDK documentation for "MappedField" states "The related field for this entity field" and I thought that meant "related" as in Foreign Key

Marcus wrote:

That's it... thanks!

The SDK documentation for "MappedField" states "The related field for this entity field" and I thought that meant "related" as in Foreign Key

Heh Yeah, that's not very well formulated . I'll change it into 'mapped'

Frans, I'm having a problem implementing the code you have provided above. My code is pasted below. I'm getting the infamous "cannot use foreach......object doesn't implement getEnumerator..." error. Do you know what is wrong? Thanks

            foreach(EntityRelation rel in EN_CUST_SQ_BANKEntity.Relations)
            {
                if(rel.RelationType == EntityRelationType.OneToMany && !rel.UtilizingPropertyIsHidden)
                {
                    if (sqBank.PrimaryKeyFields.Count == 1) 
                    {
                        // 1:n, so start entity is PK side.
                        string primaryKeyName = rel.FieldRelations[0].RelationStartField.FieldName;
                        string foreignKeyName = rel.FIeldRelations[0].RelationEndField.FieldName;

                        System.Web.HttpContext.Current.Response.Write("primary = " + primaryKeyName);
                        System.Web.HttpContext.Current.Response.Write("  foriegn = " + foreignKeyName);
                    }
                    System.Web.HttpContext.Current.Response.End();
                }
            }

Are you using the code in the snippet you posted to traverse the .lgp project object graph or the generated code? THe generated code uses a different object model.

I was using it for the generated code. I'll take a look at the documentation for the generated code. Thanks again Otis.

in that case: foreach(EntityRelation rel in (RelationCollection)EN_CUST_SQ_BANKEntity.Relations) { //... }

as the .Relations property returns an IRelationCollection type, which isn't enumerable, the RelationCollection is.