To show the values from an array

i have five dropdowns. currency,pattern,trade, risk and previous. and three lable
what i do is select the currency,pattern,trade and risk from the dropdowns and click on button. it  coppies the selected item from currency and save its copy in previous dropdown. also saves the pattern,trade, and risk in differnt arrays. and when i select and item from previous dropdown so it show the pattern,trade, and risk related to that particular item in the lables.but when i do so all the labels show only the values of risk from the arrays. can somebody tells me what is wrong. the code is given below.
 string[] _strArr;
  string[] pattern;
  string[] trade;
  string[] risk;
   

  protected void Page_Load(object sender, EventArgs e)
  {
  if (!IsPostBack)
  {
  // DropDownList 1 load code here...
  }
  if (ViewState["stringArr"] == null)
  {
  pattern = new string[Currency.Items.Count];
  trade = new string[Currency.Items.Count];
  risk = new string[Currency.Items.Count];
  }
  else
  {
  pattern = (string[])ViewState["stringArr"];
  trade = (string[])ViewState["stringArr"];
  risk = (string[])ViewState["stringArr"];
  }

  }
  protected void Button1_Click(object sender, EventArgs e)
  {
  if ((Currency.SelectedValue != "") && (!previous.Items.Contains(Currency.SelectedItem)))
  {
  previous.SelectedIndex = -1;
  previous.Items.Add(Currency.SelectedItem);
   
  pattern[previous.SelectedIndex] = Pattern.SelectedItem.ToString();
  trade[previous.SelectedIndex] = Trade.SelectedItem.ToString();
  risk[previous.SelectedIndex] = Risk.SelectedItem.ToString();
   

  ViewState["stringArr"] = pattern;
  ViewState["stringArr"] = trade;
  ViewState["stringArr"] = risk;
  }

  }
  protected void DropDownList2_SelectedIndexChanged(object sender, EventArgs e)
  {
   
 
  label1.Text = pattern[previous.SelectedIndex];
  labe2.Text = trade[previous.SelectedIndex];
  label3.Text = trade[previous.SelectedIndex];
 
  }
thanks in advance