C#NET2008 Problem Refill Listbox

[lenniekuah]

Hullo Good Guys,
I need your help. Please help me.

I am trying to reload the Listbox1 with new data contained in DataSet. I am vey confused as this error was generated :
Items collection cannot be modified when the DataSource property is set.

This is the coding that generate the error:
this.listBox1.Items.Clear();

Here are the Overall coding:

 private void FLoadListBox(string strTagName)
 {  
   this.listBox1.Items.Clear();  <--- error 
 
   if (this.txtInput.text == "Product")
     {
       string strSql = "Select Product from TblSales";
     }               
 
   else
    {
      string strSql = "Select Orders from TblSales";
    }
 
    sqlconn = new SqlConnection(connstr);
    sqlconn.Open();
 SqlDataAdapter DA = new SqlDataAdapter(strSql, sqlconn);
   System.Data.DataSet DS = new DataSet("DS");
   DS.Clear();
   DS.Tables.Clear();                  
   DA.Fill(DS, "Display");          
 
  if (this.txtInput.text == "Product")
    {
         this.listBox1.DisplayMember ="Product";
     this.listBox1.DataSource = DS.Tables["Display"];
    }  
  else
    {
     this.listBox1.DisplayMember ="Orders";
     this.listBox1.DataSource = DS.Tables["Display"];
    }
 
    sqlconn.close();
  }