title: C# Exception Handling continue on error
body: <p>I have a basic C# console application that reads a text file (CSV format) line by line and puts the data into a HashTable. The first CSV item in the line is the key (id num) and the rest of the line is the value. However I've discovered that my import file has a few duplicate keys that it shouldn't have. When I try to import the file the application errors out because you can't have duplicate keys in a HashTable. I want my program to be able to handle this error though. When I run into a duplicate key I would like to put that key into a arraylist and continue importing the rest of the data into the hashtable. How can I do this in C#</p>
  
  <p>Here is my code:</p>
  
  <hr>
  
  <p>private static Hashtable importFile(Hashtable myHashtable, String myFileName) 
          {</p>
  
  <pre><code>        StreamReader sr = new StreamReader(myFileName);
          CSVReader csvReader = new CSVReader();
          ArrayList tempArray = new ArrayList();
          int count = 0;
  
          while (!sr.EndOfStream)
          {
              String temp = sr.ReadLine();
              if (temp.StartsWith(" "))
              {
                  ServMissing.Add(temp);
              }
              else
              {
                  tempArray = csvReader.CSVParser(temp);
                  Boolean first = true;
                  String key = "";
                  String value = "";
  
                  foreach (String x in tempArray)
                  {
                      if (first)
                      {
                          key = x;
                          first = false;
                      }
                      else
                      {
                          value += x + ",";
                      }
                  }
                  myHashtable.Add(key, value);
              }
              count++;
          }
  
          Console.WriteLine("Import Count: " + count);
          return myHashtable;
      }
  </code></pre>