Question

I was wondering if it were possible to make a list from the dictionary values where the key is a specified value?

The dictionary would like this:

Sidcup – DPC1
Sidcup – DPC2
Blackheath – DPC3
Blackheath – DPC4
Bexleyheath – DPC5

In fact, I’m not entirely implementing a Dictionary as above is a good idea. Here is its implementation:

DataSet ds = EngineBllUtility.GetDPCsForImportFile(connectionString, fileID);
if (ds.Tables.Count > 0)
{
    DataTable dtDPCs = EngineBllUtility.GetDPCsForImportFile(connectionString, fileID).Tables[0];
    Dictionary<string, string> preliminaryList = new Dictionary<string, string>();

    if (dtDPCs.Columns.Contains("DPCNumber") && dtDPCs.Columns.Contains("BranchName"))
       foreach (DataRow dataRow in dtDPCs.Rows)
       {
            preliminaryList.Add(dataRow["BranchName"].ToString(), dataRow["DPCNumber"].ToString());
       }

I have the following code: (Excuse the last line, its just so you have an idea of what I’m trying to do).

foreach (string branch in branchNames)
{
    string subfolder = System.IO.Path.Combine(saveLocation, branch);
    System.IO.Directory.CreateDirectory(subfolder);

    List<string> certificateList = new List<string>();

    certificateList.Add(DPCNumber in preliminaryList where Key = branch);
}

In the above the branch is the key from the Dictionary. I need to iterate through because it needs to create a new folder and then do something with the certificateList I am creating.

Answer 1

Sure:

private static void TestZip()
    {
        Dictionary<string, string> stringstringdic = new Dictionary<string, string>();
        stringstringdic.Add("1", "One");
        stringstringdic.Add("2", "Two");
        stringstringdic.Add("3", "Three");
        stringstringdic.Add("4", "Four");
        stringstringdic = stringstringdic.Where(pair => pair.Key != "1")
                                         .ToDictionary(pair => pair.Key, pair => pair.Value);
        List<string> stringlist = stringstringdic.Keys.Concat(stringstringdic.Values).ToList();
        foreach (string str in stringlist)
        {
            Console.WriteLine(str);
        }
    }

//Output:    
//2
//3
//4
//Two
//Three
//Four

Of course, you’ll have to change the Where clause to reflect your real need.
If I understood you right, it’s like .Where(pair => pair.Key == branch)