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");  } }