Insert Data With Parameters And Sqldatasource

I have a sqldatasource in a wizard. When I click the finishbutton in the wizard I want to insert some values (from textboxes, dropdownlists in my wizard) into a mysql-database. For this I use parameters, I add some values in the design mode and some in codebehind. The parameters in codebehind are added perfectly but the other parameters in designmode (name, email) just inserts null. Why?

 
My datasource: <asp:SqlDataSource
ID="dsInsert"
InsertCommand="INSERT INTO tbltest (name, email, city) VALUES (?name, ?email, ?city)"
runat="server"
ConnectionString="<%$ ConnectionStrings:conn %>"
ProviderName="MySql.Data.MySqlClient">
<InsertParameters>
<asp:FormParameter Name="?name" ConvertEmptyStringToNull="true" Type="string" FormField="name" />
<asp:FormParameter Name="?email" ConvertEmptyStringToNull="true" Type="string" FormField="email" />
</InsertParameters>
</asp:SqlDataSource>
  
 
The codebehind:
        protected void finishButtonClick(object sender, EventArgs e)
        {
            dsInsert.InsertParameters.Add("?city", TypeCode.Int32, city.SelectedValue);
            dsInsert.Insert();
        }