<system.webServer>
    <rewrite>
      <rules>
        <rule name="Remove trailing slash" stopProcessing="true">
          <match url="(.*)/$" />
          <conditions>
            <add input="{REQUEST_FILENAME}" matchType="IsFile" negate="true" />
            <add input="{REQUEST_FILENAME}" matchType="IsDirectory" negate="true" />
          </conditions>
          <action type="Redirect" redirectType="Permanent" url="{R:1}" />
        </rule>

      </rules>
    </rewrite>
  </system.webServer>

protected void Application_BeginRequest(object sender, EventArgs e)

{

    if (Request.RawUrl.Length > 1 && Request.RawUrl.EndsWith("/"))

    {

        Response.RedirectPermanent(Request.RawUrl.Substring(0, Request.RawUrl.Length - 1), true);

    }

}