An "untyped" dataset is an instance of the DataSet class 
from the System.Data namespace. It’s called “untyped” 
because all columns are provided as the base System.Object 
type (“object” in C# and “Object” in VB.NET) and must be 
coerced to the appropriate type, e.g.

void Form1_Load(object sender, EventArgs e) {
  DataSet ds = new DataSet();
  sqlDataAdapter1.Fill(ds);
  foreach( DataRow row in ds.Tables[0].Rows ) {
    string fname = (string)row["au_fname"];
    bool contract = (bool)row["contract"];
    string item =
      string.Format("{0} has a contract: {1}", fname, 
contract);
    listBox1.Items.Add(item);
  }
}

Dataset are two types 1.Typed dataset
                      2. Untyped dataset.

In typed dataset we've autocompletion and intelisense of vs.
and also data's from datset are cached in xml format.

But in untyped dataset, it just connect with the database
and it doesn't support any other features of Vs.