跟我一起学Windows Workflow Foundation(7)-----给定制活动添加有效性验证

vlei

　　

　　给定制活动属性添加有效性验证
　　
　　这个实验也没什么可详细说的了，无非就是给我们之前发送E-Mail的活动的属性里加个验证，这里我们验证了E-mail的To和From属性是否符合邮件的格式。如果不是正确的邮件格式，我们则在编译的时候不允许进行编译。
　　下面大概过一下：
　　1. 打开我们上次的那个定制活动项目，在 SendMailActivityLibrary这个项目上添加一个新的代码文件，名称叫做ParametersValidator.cs。
　　2. 在代码文件中输入如下代码，代码继承自ActivityValidator，如果是合成的活动（就是上上次我们拼出来的那个自定义活动），那么代码应该继承自CompositeActivityValidator。 ActivityValidator在设计和运行时状态会进行验证，这些验证依赖于活动，在我们进行编译和运行时活动时，会自动运行这些代码查看我们的属性是否符合规则。
using System;
using System.Workflow.Activities;
using System.Workflow.ComponentModel;
using System.Workflow.ComponentModel.Compiler;
using System.Text.RegularExpressions;
using System.Net.Mail;
namespace SendMailActivityLibrary
{
public class ParametersValidator : ActivityValidator
{
}
}


　　3. 重写ValidateProperties方法来完成我们的验证。活动的ValidateProperties方法是在进行编译时执行的验证方法。这些验证语句将验证我们输入的这些属性是否是正确的E-mail格式
public override ValidationErrorCollection ValidateProperties(ValidationManager manager, object obj)
{
ValidationErrorCollection validationErrors = new ValidationErrorCollection(base.ValidateProperties (manager, obj));
SendMailActivity sendMailActivityToBeValidated = obj as SendMailActivity;
if (sendMailActivityToBeValidated == null)
{
throw new InvalidOperationException("Parameter obj is not of type SendMailActivity");
}
if (!IsValidEmailAddress(sendMailActivityToBeValidated.To))
{
ValidationError CustomActivityValidationError =
new ValidationError(String.Format("\'{0}\' is an Invalid destination e-mail address", sendMailActivityToBeValidated.To), 1);
validationErrors.Add(CustomActivityValidationError);
}
if (!IsValidEmailAddress(sendMailActivityToBeValidated.From))
{
ValidationError CustomActivityValidationError =
new ValidationError(String.Format("\'{0}\' is an Invalid source e-mail address", sendMailActivityToBeValidated.From), 1);
validationErrors.Add(CustomActivityValidationError);
}
return validationErrors;
}
public Boolean IsValidEmailAddress(String address)
{
// must only proceed with validation if we have data   
// to validate
if (address == null || address.Length == 0)
return true;
Regex rx = new Regex(@"[^A-Za-z0-9@\-_.]", RegexOptions.Compiled);
MatchCollection matches = rx.Matches(address);
if (matches.Count > 0)
return false;
// Must have an '@' character
int i = address.IndexOf('@');
// Must be at least three chars after the @
if (i = address.Length - 3)
return false;
// Must only be one '@' character
if (address.IndexOf('@', i + 1) >= 0)
return false;
// Find the last . in the address
int j = address.LastIndexOf('.');
// The dot can't be before or immediately after the @ char
if (j >= 0 && j