How to populate a record for database to dropdownlist?

See more:

C#

ASP.NET

MySQL

I can't populate the value of the city in a record from my database into a dropdownlist upon clicking the edit button from the gridview...

I have this button beside my GridView:

<asp:TemplateField>
                <ItemTemplate>
                    <asp:Button ID="ButtonEdit" runat="server" Text="Edit" causesvalidation = "false"
                    OnCommand="EditDetails" CommandArgument='<%# Eval("TableID").ToString() %>' CommandName="ButtonCommandEdit"
                     />
                </ItemTemplate>
        </asp:TemplateField>

And then, this: (Note that this is just EDIT button and not UPDATE button yet)

string recordID = ""; //to be used in ***
protected void EditDetails(object sender, CommandEventArgs e)
        {
            recordID = e.CommandArgument.ToString(); //to set value of ***
            GridViewUserInfoTable.Enabled = false;
            ButtonUpdate.Visible = true;
            ButtonCancel.Visible = true;
            ButtonSubmit.Visible = false;
            var connectionString = "server=localhost;uid=root;" + "pwd=xxxxx;database=xxxxx;";
            using (var connection = new MySqlConnection(connectionString))
            {
                connection.Open();
                var query = "select * from table where tableID= " + recordID; //using the value of ***
                using (var command = new MySqlCommand(query, connection))
                {
                    using (var reader = command.ExecuteReader())
                    {

                        while (reader.Read())
                        {
                            TextBoxfirstName.Text = (reader.GetString("firstName"));
                            TextBoxmiddleName.Text = (reader.GetString("middleName"));
                            TextBoxlastName.Text = (reader.GetString("lastName"));
                            TextBoxmobileNo.Text = (reader.GetString("mobileNo"));
                            TextBoxemailAddress.Text = (reader.GetString("emailAddress"));
                            TextBoxregistrationDate.Text = reader.GetDateTime("registrationDate").ToString("yyyy-MM-dd");
                            TextBoxstreet.Text = (reader.GetString("street"));
                            DropDownListCity.SelectedValue = (reader.GetString("city")); 
//i believe i need to change something here in DropDownLists
                            DropDownListRegion.SelectedValue = (reader.GetString("region"));
                            TextBoxcountry.Text = (reader.GetString("country"));
                        }
                    }
                }
            }
            if (Page.IsPostBack)
            {
                //nothing
            }
        }

Everything populates except for the drop down lists... Can someone please help me with this? All responses will be highly appreciated. Thanks in advance!