DStation has a SelectedValue which is invalid because it does not exist in the list of items.

How to solver this error? Im getting error for "DropDown"

Error: 'DStation' has a SelectedValue which is invalid because it does not exist in the list of items. Parameter name: value on line: DStation.DataBind();

My .cs code is below

string CommandText = ("select distinct StationName from stations where DeletionDate is null");
DStation.DataSource = DataManager.DatabaseManager.GetOrCreateConnection(DataManager.DatabaseManager.ConnectionType.MySQL).GetData(CommandText);
 DStation.DataTextField = "StationName";
 DStation.DataValueField = "StationName";            
 DStation.DataBind();
 DStation.Items.Insert(0, new ListItem("--Select--", "0")); 

My HTML code is below

<asp:DropDownList ID="DStation" runat="server" Width="100%"></asp:DropDownList>