public IQueryable<FinancialTransactionDetail> GetPayments( int registrationId )
{
int registrationEntityTypeId = EntityTypeCache.Read( typeof( Rock.Model.Registration ) ).Id;
return new FinancialTransactionDetailService( (RockContext)this.Context )
.Queryable( "Transaction" )
.Where( t =>
t.EntityTypeId == registrationEntityTypeId &&
t.EntityId == registrationId );
}