Script not updating
<p>I am testing a sample script. I have customized certain fields to suit me. It's a grid view with 3 filters. So, after i filter to desired course i want to, i am supposed to edit/update the <code>amount</code> value. Right now, it isn't updating. Neither does it throw up any errors. Example: if i change the value from 20-30 and select update, it shows me 20 after the page loads.</p>

<p>Here is my script.</p>

<pre class="lang-html prettyprint-override"><code>&lt;%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs"       Inherits="WebApplication1.WebForm1" %&gt;
&lt;!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"&gt;
&lt;html&gt;
&lt;head id="Head1" runat="server"&gt;
&lt;title&gt;Filtering Data In A GridView Using a DropDownList&lt;/title&gt;
&lt;/head&gt;
&lt;body&gt;
&lt;form id="form1" runat="server"&gt;
  &lt;b&gt;Choose a Course:&lt;/b&gt;
  &lt;asp:DropDownList ID="DropDownList1" DataSourceID="SqlDataSource2" AutoPostBack="True"
    DataTextField="Course" Runat="server" DataValueField="Course" /&gt;
  &lt;asp:SqlDataSource ID="SqlDataSource2" Runat="server" SelectCommand="SELECT Distinct Course FROM tmdsi"
    ConnectionString="&lt;%$ ConnectionStrings:testConnectionString %&gt;" 
      ProviderName="&lt;%$ ConnectionStrings:testConnectionString.ProviderName %&gt;" /&gt;

      &lt;b&gt;Choose a Location:&lt;/b&gt;
         &lt;asp:DropDownList ID="DropDownList2" DataSourceID="SqlDataSource3" AutoPostBack="True"
    DataTextField="Location" Runat="server" DataValueField="Location" /&gt;
  &lt;asp:SqlDataSource ID="SqlDataSource3" Runat="server" SelectCommand="SELECT Distinct Location FROM tmdsi"
    ConnectionString="&lt;%$ ConnectionStrings:testConnectionString %&gt;" 
      ProviderName="&lt;%$ ConnectionStrings:testConnectionString.ProviderName %&gt;" /&gt;

       &lt;b&gt;Choose a Language:&lt;/b&gt;
         &lt;asp:DropDownList ID="DropDownList3" DataSourceID="SqlDataSource4" AutoPostBack="True"
    DataTextField="Language" Runat="server" DataValueField="Language" /&gt;
  &lt;asp:SqlDataSource ID="SqlDataSource4" Runat="server" SelectCommand="SELECT Distinct Language FROM tmdsi"
    ConnectionString="&lt;%$ ConnectionStrings:testConnectionString %&gt;" 
      ProviderName="&lt;%$ ConnectionStrings:testConnectionString.ProviderName %&gt;" /&gt;

  &lt;br /&gt;
  &lt;br /&gt;
  &lt;asp:GridView ID="GridView1" AllowSorting="True" AllowPaging="True" Runat="server"
    DataSourceID="SqlDataSource1" AutoGenerateEditButton="True" AutoGenerateColumns="False"&gt;
    &lt;Columns&gt;

      &lt;asp:BoundField ReadOnly="true" HeaderText="Course" DataField="Course" /&gt;
      &lt;asp:BoundField ReadOnly="true" HeaderText="Location" DataField="Location"  /&gt;
      &lt;asp:BoundField ReadOnly="true" HeaderText="Language" DataField="Language" /&gt;
      &lt;asp:BoundField HeaderText="Amount" DataField="Amount" /&gt;
    &lt;/Columns&gt;
  &lt;/asp:GridView&gt;
  &lt;asp:SqlDataSource ID="SqlDataSource1" Runat="server" SelectCommand="SELECT Course,Language, Location, Amount FROM tmdsi Where Course = @Course and Location = @Location and Language = @Language "
    UpdateCommand="UPDATE tmdsi SET Amount = @Amount where Course = @Course and Location = @Location and Language=@Language "
    ConnectionString="&lt;%$ ConnectionStrings:testConnectionString %&gt;" 
    ProviderName="&lt;%$ ConnectionStrings:testConnectionString.ProviderName %&gt;"&gt;
    &lt;SelectParameters&gt;
    &lt;asp:ControlParameter Name="Course" ControlID="DropDownList1" /&gt;
    &lt;asp:ControlParameter Name="Location" ControlID="DropDownList2" /&gt;
    &lt;asp:ControlParameter Name="Language" ControlID="DropDownList3" /&gt;
    &lt;/SelectParameters&gt;
    &lt;UpdateParameters&gt;
      &lt;asp:Parameter Name="Course" /&gt;
      &lt;asp:Parameter Name="Location" /&gt;
      &lt;asp:Parameter Name="Language" /&gt;
      &lt;asp:Parameter Name="Amount" /&gt;
    &lt;/UpdateParameters&gt;        
  &lt;/asp:SqlDataSource&gt;
&lt;/form&gt;
</code></pre>

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