title: Having duplicate values in DropDownList selection cause mismatch selection
body: <p>I have a <code>DropDownList</code>, which is bound to the database. The values in the <code>DropDownList</code> list may be something like:</p>
  
  <blockquote>
    <p>Bedroom1<br>
       Bedroom2<br>
       Kitchen1<br>
       Kitchen2  </p>
  </blockquote>
  
  <p>When these items are list in <code>DropDownList</code>, having selected "Bedroom2", selects "Bedroom1" itself, but having selected "Kitchen2", selects "Kitchen1". </p>
  
  <p>This <code>DropDownList</code> is further bound to another <code>DropDownList</code>. I have set AutoPostBack for both the <code>DropDownList</code>s. I have bound the datasource from code behind. </p>
  
  <p>What might have gone wrong?</p>
  
  <p>Databinding code:</p>
  
  <pre><code>SqlDataAdapter myda = new SqlDataAdapter("Select * FROM " + Label3.Text, con);
  DataSet ds = new DataSet();
  myda.Fill(ds, "Table");
  LOC_LIST2.DataSource = ds.Tables[0];
  LOC_LIST2.DataTextField = ds.Tables[0].Columns["Location_Instance"].ColumnName.ToString(); 
  LOC_LIST2.DataValueField=ds.Tables[0].Columns["Location_Type"].ColumnName.ToStri??ng(); 
  LOC_LIST2.DataBind(); 
  LOC_LIST2.Items.Insert(0, new ListItem("---Choose One Location---", "-1"));
  </code></pre>
  
  <p>Therefore in the above code Location_Instance is the number of locations(Location_Type) that is added and store in database and the same is retrieved in the above <code>DropDownList</code>.</p>
  
  <p>This is a very serious issue, can someone please help me on this asap?</p>