C＃Lazy属性 [英] C# Lazy property

问题描述

我的类中有一个Lazy属性：

  private Lazy< ISmtpClient> SmtpClient 
 {
 get 
 {
 return new Lazy< ISmtpClient>（（）=> _objectCreator.Create< ISmtpClient>（），true）; 
} 
} 
  

也是一个使用这种方法的方法：

  public void SendEmail（MailMessage message）
 {
 SmtpClient.Value.ServerName =testServer; 
 SmtpClient.Value.Port = 25; 
 
 SmtpClient.Value.Send（message）; 
} 
  

但是在我的SmtpClient中，Send（string message）我在上面的SendEmail（MailMessage消息）方法中初始化为null。

如何解决此问题？

提前感谢。

p>当使用 Lazy< T> 时，会暴露实际类型的属性，并且有一个 Lazy< T> 实例。您不会在每次访问媒体资源时创建新的媒体：

  Lazy< ISmtpClient> _smtpClient = 
 new Lazy< ISmtpClient>（（）=> _objectCreator.Create< MySmtpClient>（），true）; 
 
 private ISmtpClient SmtpClient 
 {
 get 
 {
 return _smtpClient.Value; 
} 
} 
  

现在，第一次 SmtpClient 属性，对象创建者创建 MySmtpClient 的新实例。返回。

使用方法如下：

  public void SendEmail（MailMessage message）
 {
 SmtpClient.ServerName =testServer; 
 SmtpClient.Port = 25; 
 
 SmtpClient.Send（message）; 
} 
  

I have a Lazy property in my class:

private Lazy<ISmtpClient> SmtpClient
    {
        get
        {
            return new Lazy<ISmtpClient>(() => _objectCreator.Create<ISmtpClient>(), true);
        }
    }

Also a methode that uses this proptery:

public void SendEmail(MailMessage message)
    {
        SmtpClient.Value.ServerName = "testServer";
        SmtpClient.Value.Port = 25;

        SmtpClient.Value.Send(message);
    }

But in my SmtpClient, in Send(string message) methode are all the propteries that i initialized in the above SendEmail(MailMessage message) methode, null.

How can i fix this?

Thanks in advance.

解决方案

You are using Lazy<T> wrong.

When using Lazy<T> you expose a property of the actual type and you have one Lazy<T> instance. You don't create a new one every time the property is accessed:

Lazy<ISmtpClient> _smtpClient =
    new Lazy<ISmtpClient>(() => _objectCreator.Create<MySmtpClient>(), true);

private ISmtpClient SmtpClient
{
    get
    {
        return _smtpClient.Value;
    }
}

Now, the first time the SmtpClient property is accessed, the object creator creates a new instance of MySmtpClient. This is returned. On subsequent calls, the same instance is returned.

The usage would be like this:

public void SendEmail(MailMessage message)
{
    SmtpClient.ServerName = "testServer";
    SmtpClient.Port = 25;

    SmtpClient.Send(message);
}

这篇关于C＃Lazy属性的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！