public class ResponseContentLength : ValidationRule
{
	public int Length { get; set; }                   //输入的长度
	public bool PassIfEqualsToContentLength { get; set; }
 
	public override void Validate(object sender, ValidationEventArgs e)
	{
		if (e.Response != null)
		{
			e.IsValid = !((e.Response.ContentLength == Length) ^ PassIfEqualsToContentLength);
		}
		if (!e.IsValid)
		{
			e.Message = string.Format("The length of the ContentLength: {0} is not equal to the expected result: {1}.", e.Response.ContentLength, Length);
		}
	}
}

public class FilterRuleWebPlugin : Microsoft.VisualStudio.TestTools.WebTesting.WebTestPlugin
{
	static readonly string key = "RuleName";
	public override void PreWebTest(object sender, PreWebTestEventArgs e)
	{
		base.PreWebTest(sender, e);
		//Add the new context
		if (!e.WebTest.Context.ContainsKey(key))
		{
			e.WebTest.Context.Add(key, string.Empty);
		}
		string filter = GetFilter();
		if (string.IsNullOrEmpty(filter))
		{
			e.WebTest.Context[key] = "default";
		}
		else
		{
			e.WebTest.Context[key] = filter;
		}
	}
 
	private string GetFilter()
	{
		string filter = string.Empty;
		XmlDocument doc = new XmlDocument();
		try
		{
			doc.Load("Config.xml");
			if (doc != null)
			{
				filter = doc.SelectSingleNode("Settings/Filter").InnerText;
			}
		}
		catch (Exception)
		{
			return "LoadFilterError";
		}
		return filter;
	}
}