what is the difference between list<> and dictionary<> in c#

Question

I have a strange doubt regarding list and dictionary in c#

In a list we add items to list by using the following method

using System.Collections.Gen         


        

Answer 1

I have a class library which accesses a variety of T-sql sprocs; each sproc returns a single row but varying columns. I needed a general purpose solution for an retrieving the values and Dictionary<> provided a much cleaner solution than List<>.

The class common to all of the wrappers declares

public Dictionary datadict = new Dictionary();

and

public Dictionary LoadData(string sproc, string paramName, string paramValue)

Invoking a Reader, the datadict is loaded with

for (int i = Reader.FieldCount; i != 0; i--)
 {
  datadict.Add(Reader.GetName(i - 1).Trim(), Reader.GetString(i - 1).Trim());
 }

and returns datadict to the calling class which can then retrieve the data much like Reader does; E.g.:

datadict = myData.LoadData("spGetSSN", "", "");
  ssn1 = datadict["SSN1"];
  ssn2 = datadict["SSN2"];
  ssn3 = datadict["SSN3"];

Much cleaner for me that List<>.