使用正则表达式验证，以确保一个字符串包含特定的子 [英] use regex validator to ensure a string contains particular substring

问题描述

我想使用正则表达式验证，以保证一定的字符串变量包含子www.youtube.com/watch?v =，我会怎么做此？

  [RegularEx pression（）]
[必需（的ErrorMessage =Youtube链接是必需）]
[StringLength（100的ErrorMessage =Youtube链接不能超过50个字符）]
公共字符串YoutubeLink {搞定;组; }
 

解决方案

 如果（YoutubeLink.Contains（www.youtube.com/watch?v=））
{
   // ...
}
 

http://msdn.microsoft.com/en-us/library/ dy85x1sa.aspx

要使用RegularEx pression属性，必须指定正则表达式的使用方法：

  [RegularEx pression（WWW \\\\。\\\\的YouTube。com /手表\\\\？V =的ErrorMessage =链接是不正确）]
公共字符串YoutubeLink {搞定;组; }
 

<一个href=\"http://msdn.microsoft.com/en-us/library/system.componentmodel.dataannotations.regularex$p$pssionattribute.aspx\" rel=\"nofollow\">http://msdn.microsoft.com/en-us/library/system.componentmodel.dataannotations.regularex$p$pssionattribute.aspx

---

我想你可能想要的是来检查任何类型的URL开始。在这种情况下，你可以使用 @^（HTTP：//）？？？（WWW \\）的YouTube \\ .COM /手表\\ V =的正则表达式字符串。

<一个href=\"http://regexpal.com/?flags=m&regex=%5E%28http%3A%2F%2F%29%3F%28www%5C.%29%3Fyoutube%5C.com%2Fwatch%5C%3Fv%3D&input=http%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3D12323456%0D%0A%0D%0Ahttp%3A%2F%2Fyoutube.com%2Fwatch%3Fv%3D12323456%0D%0A%0D%0Awww.youtube.com%2Fwatch%3Fv%3D12323456%0D%0A%0D%0Ayoutube.com%2Fwatch%3Fv%3D12323456%0D%0A%0D%0Ahttp%3A%2F%2Fwww.goingbananas.com%0D%0A%0D%0Awww.goingbananas.com%0D%0A%0D%0Ahttp%3A%2F%2Fgoingbananas.com%0D%0A%0D%0Agoingbananas.com\"相对=nofollow>见这是什么会匹配一个例子

I want to use a regex validator to ensure that a certain string variable contains the substring "www.youtube.com/watch?v=", how would I do this?

[RegularExpression()]
[Required(ErrorMessage = "Youtube link is Required")]
[StringLength(100, ErrorMessage="Youtube link cannot exceed 50 characters")]
public string YoutubeLink { get; set; }

解决方案

if (YoutubeLink.Contains("www.youtube.com/watch?v="))
{
   //...
}

http://msdn.microsoft.com/en-us/library/dy85x1sa.aspx

To use the RegularExpression attribute, you must specify the regex to use :

[RegularExpression("www\\.youtube\\.com/watch\\?v=", ErrorMessage = "Link is incorrect")]
public string YoutubeLink { get; set; } 

http://msdn.microsoft.com/en-us/library/system.componentmodel.dataannotations.regularexpressionattribute.aspx

---

I think what you might want is to check for any type of URL beginning. In that case, you would use @"^(http://)?(www\.)?youtube\.com/watch\?v=" as the regex string.

See an example of what this would match

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