using foreach for C# for Email in Asp.NetCore Web API

Question

I have two different IEnumerable<> one to get id from gmail inbox and the other IEnumerable<> is to get list of MailMessage like this code below

          client.DefaultMailbox = "INBOX";
          IEnumerable<uint> sids = client.Search(SearchCondition.Unseen());
          IEnumerable<MailMessage> AllMessage = client.GetMessages(sids);
          List<LiteInbox> allmail = new List<LiteInbox>();

Now i want to use two foreach to get particular Id for MailMessage coming from gmail inbox below if i iterate foreach inside foreach that will fecth the each id for each mail

 foreach (uint ids in sids)
  {
      id = ids;
      LiteInbox lite=new LiteInbox();

      foreach(var mail in AllMessage )
      {
         lite.id=id;
         lite.sender=mail.sender;
         lite.subject=mail.subject;
      }

   }

But when i run my code it first iterate the first foreach for all email before it then iterate the second foreach meaning if there is 4 unRead mail in my gmail, it will bring 16 unread emails and iterate each 4 with a single Id like this

     {   [
   {
    id: 1,
    subject: welcome,
    body:hbjdbjddjh,
    sender: wealsegun@gmail.com     },
{
    id: 1,
    subject: welcome,
    body:hbjdbjddjh,
    sender: wealsegun@gmail.com      },
{
    id: 1,
    subject: welcome,
    body:hbjdbjddjh,
    sender: wealsegun@gmail.com      },
{
    id: 1,
    subject: welcome,
    body:hbjdbjddjh,
    sender: wealsegun@gmail.com      },
],
   [
   {
    id: 2,
    subject: welcome,
    body:hbjdbjddjh,
    sender: wealsegun@gmail.com      },
{
    id: 2,
    subject: welcome,
    body:hbjdbjddjh,
    sender: wealsegun@gmail.com      },
{
    id: 2,
    subject: welcome,
    body:hbjdbjddjh,
    sender: wealsegun@gmail.com      },
{
    id: 2,
    subject: welcome,
    body:hbjdbjddjh,
    sender: wealsegun@gmail.com     },
]}

Answer 1

You need to retrieve every sid associated to every Email if the class MailMessage has a sid property (I doubt, is MailMessage class the .Net framework one?) you need to modify the signature of one or both your Search and GetMessages so it returns something like a

List<Pair<uint, MailMessage>> 

where every element of the list is the message and its ID

After that, you will not need the double foreach

Answer 2

Assuming that the order of AllMessage and sids is the same, and the number of elements in these lists is equal (otherwise I wouldn't know how to assign the correct id to a message) you can do the following

for (int i = 0; i < AllMessage.Count; i++) {
    LiteInbox lite=new LiteInbox();
    lite.id = sids[i];
    lite.sender=AllMessage[i].sender;
    lite.subject=AllMessage[i].subject;
    allmail.Add(lite);    
}

alternatively with foreach

int i = 0;  //you'll need that index to access the corresponding element in the other list
foreach (int id in sids) {
    LiteInbox lite=new LiteInbox();
    lite.id = id;
    lite.sender=AllMessage[i].sender;
    lite.subject=AllMessage[i].subject;
    allmail.Add(lite);            
    i++;
}