parameterCheck.cs
public class parameterCheck{
public static bool isEmail(string emailString){
return System.Text.RegularExpressions.Regex.IsMatch(emailString, "['\\w_-]+(\\.
['\\w_-]+)*@['\\w_-]+(\\.['\\w_-]+)*\\.[a-zA-Z]{2,4}");
}
public static bool isInt(string intString){
return System.Text.RegularExpressions.Regex.IsMatch(intString ,"^(\\d{5}-\\d{4})|
(\\d{5})$");
}
public static bool isUSZip(string zipString){
return System.Text.RegularExpressions.Regex.IsMatch(zipString ,"^-[0-9]+$|^[0-9]
+$");
}
}

<appSettings>
<add key="safeParameters" value="OrderID-int32,CustomerEmail-email,ShippingZipcode-
USzip" />
</appSettings>

protected void Application_BeginRequest(Object sender, EventArgs e){
String[] safeParameters = System.Configuration.ConfigurationSettings.AppSettings
["safeParameters"].ToString().Split(',');
for(int i= 0 ;i < safeParameters.Length; i++){
String parameterName = safeParameters[i].Split('-')[0];
String parameterType = safeParameters[i].Split('-')[1];
isValidParameter(parameterName, parameterType);
}
}
public void isValidParameter(string parameterName, string parameterType){
string parameterValue = Request.QueryString[parameterName];
if(parameterValue == null) return;
if(parameterType.Equals("int32")){
if(!parameterCheck.isInt(parameterValue)) Response.Redirect("parameterError.aspx");
}
else if (parameterType.Equals("double")){
if(!parameterCheck.isDouble(parameterValue)) Response.Redirect("parameterError.aspx");
}
else if (parameterType.Equals("USzip")){
if(!parameterCheck.isUSZip(parameterValue)) Response.Redirect("parameterError.aspx");
}
else if (parameterType.Equals("email")){
if(!parameterCheck.isEmail(parameterValue)) Response.Redirect("parameterError.aspx");
}
}