public void LinqJoin()
{
using (var db = Helper.CreatePCORIDataContext(ConnectionString))
{
var query = db.ReportedOutcomeCommonMeasures
.Join(db.Encounters, pro => pro.PatientID, enc => enc.PatientID, (pro, enc) => new { PRO = pro, ENC = enc });
Logger.Debug(query.Expression.ToString());
var pe_pro = Expression.Parameter(typeof(ReportedOutcome), "pro");
var pe_enc = Expression.Parameter(typeof(Encounter), "enc");
var joinType = TypeBuilderHelper.CreateType("PRO_Enc", new IPropertyDefinition[] {
new TypedPropertyDefinition <ReportedOutcome> {
Name = "PRO"
},
new TypedPropertyDefinition <Encounter> {
Name = "ENC"
}
});
var joinBindings = new[] {
Expression.Bind(joinType.GetProperty("PRO"), pe_pro),
Expression.Bind(joinType.GetProperty("ENC"), pe_enc)
};
var resultSelector = Expression.Lambda(
Expression.MemberInit(Expression.New(joinType), joinBindings),
pe_pro,
pe_enc
);
var joinCall = Expression.Call(
typeof(Queryable),
"Join",
new Type[] {
typeof(ReportedOutcome),
typeof(Encounter),
typeof(string),
joinType
},
new Expression[] {
db.ReportedOutcomeCommonMeasures.AsQueryable().Expression,
db.Encounters.AsQueryable().Expression,
Expression.Quote(Expression.Lambda(Expression.Property(pe_pro, "PatientID"), pe_pro)),
Expression.Quote(Expression.Lambda(Expression.Property(pe_enc, "PatientID"), pe_enc)),
Expression.Quote(resultSelector)
}
);
Logger.Debug(joinCall.ToString());
}
}