Question

Dictionary<int, string> lstSrc = new Dictionary<int, string>();
            Dictionary<int, string> lstDest = new Dictionary<int, string>();

        lstSrc.Add(1, "All");
        lstSrc.Add(2, "Weekday");
        lstSrc.Add(3, "WeekEnd");

        lstDest.Add(1, "All");
        lstDest.Add(2, "X1");
        lstDest.Add(3, "X2");
        lstDest.Add(4, "Weekday");
        lstDest.Add(5, "WeekEnd");

Compare only when name matches in Source and Destination

  var matchingItems = lstDest
                    .Where(l2 => lstSrc.Any(l1 => l1.Value.Equals(l2.Value))).ToList();
                matchingItems.AddRange(lstDest.Except(matchingItems));

This query gives result as see in attached image how to get that result without using LINQ ?

How i can achieve this ?

  [1]: https://i.stack.imgur.com/FLicZ.png

Answer 1

To get the matching items you could use a query like this:

var matchingItems = List2
    .Where(l2 => List1.Any(l1 => l1.TimeGroupName.Equals(l2.TimeGroupName));
matchingItems.AddRange(List2.Except(matchingItems)));

Edited: equivalent without using Linq: (It’s easy to forget how much boiler plate Linq saves you from writing!)

// Get the matching items
List<TIMEGROUPINFO> matchingItems = new List<TIMEGROUPINFO>();
foreach (TIMEGROUPINFO l1 in List1)
{
    foreach (TIMEGROUPINFO l2 in List2)
    {
       if (l1.TimeGroupName.Equals(l2.TimeGroupName))
       {
            matchingItems.Add(l1);
            continue;
       }
    }
 }

 // Append the items from List2 which aren't already in the list:
 foreach (TIMEGROUPINFO l2 in List2)
 {
     bool exists = false;
     foreach (TIMEGROUPINFO match in matchingItems)
     {
         if (match.TimeGroupName.Equals(l2.TimeGroupName))
         {
             // This item is already in the list.
             exists = true;
             break;
         }
     }

     if (exists = false)
         matchingItems.Add(l2);
 }