Simple Form/DB Insert Question

I'm trying to wrap my head around inserting values into a table w/ SQLDataSource. What I'm trying to do is have a form where users can submit their feedback and their responses would get put into a table on the backend. It would store not only their comments, but their userid, the url that they were on last, and which area they're from. The trouble is, I have no idea if I'm coding this correctly. On the submit

Here is the form:

    <form id="form1" runat="server">
    <asp:SqlDataSource runat="server" ID="feedbackSQL" InsertCommand="insertfeedback_sp" InsertCommandType="StoredProcedure" connectionstring="<%$ ConnectionStrings:Test%>">
        <InsertParameters>
            <asp:Parameter Name="ID" Type="Int16" />
            <asp:Parameter Name="Region" Type="String" />
            <asp:Parameter Name="Querystring" Type="String" />
            <asp:FormParameter Name="Comments" FormField="Comment" />
        </InsertParameters>
   
    </asp:SqlDataSource>
    <div>
        <asp:TextBox ID="Comment" runat="server" Height="200px" Width="350px"></asp:TextBox><br />
        <asp:Button ID="Submit" OnClientClick="btn_Submit" runat="server" BackColor="White"  Font-Names="Arial" Font-Size="X-Small"
            Text="Submit" />&nbsp;&nbsp;
        <asp:Button ID="Cancel" runat="server" BackColor="White"  Font-Names="Arial" Font-Size="X-Small"
            Text="Cancel" OnClientClick='javascript: window.close()' />&nbsp; &nbsp;
        <asp:Button ID="Clear" runat="server" BackColor="White"  Font-Names="Arial" Font-Size="X-Small"
            Text="Clear" OnClientClick='javascript: ClearBox(Comment)' />
    </div>
    </form>

Here is the backend:


    protected void btn_Submit(object sender, EventArgs e)
    {
        feedbackSQL.InsertParameters["ID"].DefaultValue = UserId ;
        feedbackSQL.InsertParameters["Region"].DefaultValue = Region;
        feedbackSQL.InsertParameters["Comments"].DefaultValue = Comment.Text.ToString();
        feedbackSQL.InsertParameters["Querystring"].DefaultValue = URL.ToString();
    }

When I test it out. Nothing shows up in my database table. I also have another problem, ID is stored in my table as an int, but when I try to set it's value in btn_Submit and try to compile it, I get a "cannont convert 'int' to 'string'" error. Am I missing something here? Any help would be much appreciated, thanks :)