Question

Assuming I have some objects like this:

Class NetworkSwitch
{  
   private String _name; 
   String name { get {return _name;} set {_name=value;}}
   Dictionary<int, VLAN> VLANDict = new Dictionary<int, NetworkSwitch>();

public List<CiscoSwitch> GetAllNeigbors()
         {
           List<CiscoSwitch> templist = new List<CiscoSwitch>();

        foreach (KeyValuePair<int, CiscoVSAN> vlanpair in this.VLANDict)
        {

            templist.AddRange((vlanpair.Value.NeighborsList.Except(templist, new SwitchByNameComparer())).ToList());
        }
        return templist;
}

Class VLAN
{ 
  private Int _VLANNum;
  Int VLANNum {get {return _VLANNum ;} set {_VLANNum =value;}}

  //a neighbor is another switch this switch is connected to in this VLAN
  // the neighbor may not have all same VLANs
  List<NetworkSwitch> Neighbors = new List<NetworkSwitch>();
}

the above is designed that way because two switches that are physically connected may not have all the same VLANs assigned. what I am attempting to do is step through the Neighbors list in each VLAN on a given switch and update the reference to another switch if the name matches one in an input list. Here is what I tried and it won’t compile. I am wondering if LINQ can do it in place somehow, or if there is a better approach.

// intersect is the input list of NetworkSwitch objects
//MyNetworkSwitch is a previously created switch

foreach (NetworkSwitch ns in intersect)
{
  foreach (KeyValuePair<int, VLAN> vlanpair in MyNetworSwitch.VLANDict)
  {
      foreach (CiscoSwitch neighbor in vlanpair.Value.Neighbors)
      {   // this is the line that fails - I can't update neighbor as it is part of the foreach
          if (ns.name == neighbor.name) { neighbor = ns; }
      }
  }
}

Another question – I added the method that gets all the neighbors for a NetworkSwitch object. Assuming I were to get that list, then update it with references to a different instance of the switch with the same name, would that update the reference in the VLAN for the NetworkSwitch object?

Answer 1

Something like this should work:

        foreach (NetworkSwitch ns in intersect) 
        {   
            foreach (KeyValuePair<int, VLAN> vlanpair in ns.VLANDict)
            {
                if(vlanpair.Value.Neighbors.RemoveAll(n => n.name == ns.name) > 0)
                    vlanpair.Value.Neighbors.Add(ns);
            } 
        }