Datagrid

@Lakshmanan: DataTable will not be created with name StudentInfo. So don't pass StudentInfo as DataMember. DataTable inside DataSet will created with the name Table,Table1, Table2 and so on... when we use SqlDataAdapter to fill the dataset. Unless we specify the names of table.

The problem is in using DataMember. Since you have used sql query to fill dataset so the genereted dataset will contains tables with the name Tabel1 and not as Student.

Just remove the last line and it will work.
dataGridView1.DataMember = "Student";                 //Remove it.

You use this method for showing data in datagrid view from database.

   public void displayDataGridView()
   {
        SqlConnection con = new SqlConnection("server MUNESH\\SQL2008R2;Database=data;UID=sa;Password=123;");
        SqlCommand cmd = new SqlCommand("Select * from data1", con);
        try
        {
            con.Open();
            SqlDataAdapter da = new SqlDataAdapter();
            da.SelectCommand = cmd;
            DataTable dt = new DataTable();
            da.Fill(dt);
            dataGridView1.DataSource = dt;
            con.Close();
        }
        catch (Exception ec)
        {
            MessageBox.Show(ec.Message);
        }
}

Modify your code as below

string connectionString = "Data Source=(local);Initial Catalog=StudentRegistration;Integrated Security=True";
            string sql = "SELECT * FROM StudentInfo";
            SqlConnection connection = new SqlConnection(connectionString);
            SqlDataAdapter dataadapter = new SqlDataAdapter(sql, connection);
            DataSet ds = new DataSet();
            connection.Open();
            dataadapter.Fill(ds, "Student");
            connection.Close();
            dataGridView1.DataSource = ds;
            dataGridView1.DataMember = "Student";