Question: I just want an ASP.NET DropDownList with no selected item. Setting SelectedIndex to -1 is of no avail, so far. I am using Framework 3.5 with AJAX, i.e. this DropDownList is within an UpdatePanel.
Here is what I am doing:

```
    protected void Page_Load (object sender, EventArgs e)
    {
        this.myDropDownList.SelectedIndex = -1;
        this.myDropDownList.ClearSelection();

        this.myDropDownList.Items.Add("Item1");
        this.myDropDownList.Items.Add("Item2");
    }

```

The moment I add an element in the DropDown, its SelectedIndex changes to 0 and can be no more set to -1 (I tried calling SelectedIndex after adding items as well)... What I am doing wrong? Ant help would be appreciated!

Answer: 
The selectedIndex can only be -1 when the control is first initalised and there is no items within the collection.

It's not possible to have no item selected in a web drop down list as you would on a WinForm.

I find it's best to have:
this.myDropDownList.Items.Add(new ListItem("Please select...", ""));

This way I convey to the user that they need to select an item, and you can check SelectedIndex == 0 to validate
Please try below syntax:

```
DropDownList1.SelectedIndex = DropDownList1.Items.IndexOf(DropDownList1.Items.FindByValue("Select"))

```

or

```
DropDownList1.SelectedIndex = DropDownList1.Items.IndexOf(DropDownList1.Items.FindByText("SelectText"))

```

or 

```
DropDownList1.Items.FindByText("Select").selected =true

```

For more info :
<http://vimalpatelsai.blogspot.in/2012/07/dropdownlistselectedindex-1-problem.html>