ASP.NET Potentially Dangerous Request
<p>In my ASP.NET application I am logging any application errors that occur and one that ocassionally comes up is:</p>

<pre><code>A potentially dangerous Request.Form value was detected from the client (ctl00$MainContent$ddl_Months="&lt;a"). 
</code></pre>

<p>I understand that this is to do with the <code>&lt;</code> - however the <code>DropDownList</code> does not contain this.</p>

<p><strong>Markup:</strong></p>

<p><img src="http://i.stack.imgur.com/DSr39.png" alt="enter image description here"></p>

<pre><code>&lt;select name="ctl00$MainContent$ddl_Months" onchange="javascript:setTimeout(&amp;#39;__doPostBack(\&amp;#39;ctl00$MainContent$ddl_Months\&amp;#39;,\&amp;#39;\&amp;#39;)&amp;#39;, 0)" id="ctl00_MainContent_ddl_Months"&gt;
    &lt;option selected="selected" value="201011"&gt;201011&lt;/option&gt;
    &lt;option value="201010"&gt;201010&lt;/option&gt;
    &lt;option value="200906"&gt;200906&lt;/option&gt;
    &lt;option value="200905"&gt;200905&lt;/option&gt;
    &lt;option value="200904"&gt;200904&lt;/option&gt;
&lt;/select&gt;
</code></pre>

<p><strong>Code:</strong></p>

<p>Markup</p>

<pre><code>   &lt;asp:DropDownList ID="ddl_Months" runat="server" AutoPostBack="true" OnSelectedIndexChanged="ddl_Months_SelectedIndexChanged" /&gt;
</code></pre>

<p>Code behind</p>

<pre><code>DataTable tblMonths = GlobFunctions.GetData("GetBureauReportsMonths", GlobVar.conStrX, new SqlParameter[1]
{
    new SqlParameter("@BureauNumber", BureauCode)
});

List&lt;string&gt; months = new List&lt;string&gt;();

for (int i = 0; i &lt; tblMonths.Rows.Count; i++)
{
    months.Add(Server.HtmlEncode(tblMonths.Rows[i][0].ToString()));
}

ddl_Months.DataSource = months;

ddl_Months.DataBind();
</code></pre>

<p>I am unable to replicate this error and was wondering what options are available to me to solve this issue?</p>
