西安网站建设西安,网站制作企业首页,做网站应下哪个软件,英文淘宝网站建设简单的邮箱格式校验方式Intro前段时间有一个验证邮箱格式的小需求#xff0c;然后突然发现了一种非常简单的邮箱格式判断方式Implement直接来看实现public static bool IsEmailAddress(string email)
{if (string.IsNullOrWhiteSpace(email))return false;var symbolIndex em… 简单的邮箱格式校验方式Intro前段时间有一个验证邮箱格式的小需求然后突然发现了一种非常简单的邮箱格式判断方式Implement直接来看实现public static bool IsEmailAddress(string email)
{if (string.IsNullOrWhiteSpace(email))return false;var symbolIndex email.IndexOf();return symbolIndex 0 symbolIndex email.Length - 1 symbolIndex email.LastIndexOf();
}在之前的认知里一般判断邮箱格式都是用一个正则表达式有时候正则表达式还可能会特别复杂在老的 .NET framework 中 EmailAddress 的判断使用的是一个很复杂的一个正则表达式const string pattern ^((([a-z]|\d|[!#\$%\*\\-\/\?\^_{\|}~]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])(\.([a-z]|\d|[!#\$%\*\\-\/\?\^_{\|}~]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF]))*)|((\x22)((((\x20|\x09)*(\x0d\x0a))?(\x20|\x09))?(([\x01-\x08\x0b\x0c\x0e-\x1f\x7f]|\x21|[\x23-\x5b]|[\x5d-\x7e]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(\\([\x01-\x09\x0b\x0c\x0d-\x7f]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF]))))*(((\x20|\x09)*(\x0d\x0a))?(\x20|\x09))?(\x22)))((([a-z]|\d|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(([a-z]|\d|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])([a-z]|\d|-|\.|_|~|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])*([a-z]|\d|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])))\.)(([a-z]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(([a-z]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])([a-z]|\d|-|\.|_|~|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])*([a-z]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])))\.?$;可以参考https://referencesource.microsoft.com/#System.ComponentModel.DataAnnotations/DataAnnotations/EmailAddressAttribute.cs,54而在 .NET Core 中就比较简单了没有用到正则前面的实现也是来自于 .NET Core EmailAddressAttribute 的实现实现如下public sealed class EmailAddressAttribute : DataTypeAttribute
{public EmailAddressAttribute(): base(DataType.EmailAddress){// Set DefaultErrorMessage not ErrrorMessage, allowing user to set// ErrorMessageResourceType and ErrorMessageResourceName to use localized messages.DefaultErrorMessage SR.EmailAddressAttribute_Invalid;}public override bool IsValid(object value){if (value null){return true;}if (!(value is string valueAsString)){return false;}// only return true if there is only 1 character// and it is neither the first nor the last characterbool found false;for (int i 0; i valueAsString.Length; i){if (valueAsString[i] ){if (found || i 0 || i valueAsString.Length - 1){return false;}found true;}}return found;}
}通过这种方式我们可以提高判断邮箱格式的性能又不必维护正则表达式了。总结有且仅有一个并且前后都有字符More有一点需要注意在上面的 EmailAddressAttribute 的实现中如果值是 null 也会认为是“合法”的这里的“合法”并不是说邮箱格式合法而是说验证可以通过实际情况下一般我们是会认为这并不是一个合法的邮箱Referenceshttps://github.com/dotnet/runtime/blob/main/src/libraries/System.ComponentModel.Annotations/src/System/ComponentModel/DataAnnotations/EmailAddressAttribute.cshttps://github.com/dotnet/runtime/blob/v5.0.0/src/libraries/System.ComponentModel.Annotations/src/System/ComponentModel/DataAnnotations/EmailAddressAttribute.cshttps://github.com/dotnet/corefx/blob/v3.0.0/src/System.ComponentModel.Annotations/src/System/ComponentModel/DataAnnotations/EmailAddressAttribute.cshttps://github.com/dotnet/corefx/blob/v2.2.0/src/System.ComponentModel.Annotations/src/System/ComponentModel/DataAnnotations/EmailAddressAttribute.cshttps://github.com/dotnet/corefx/blob/v2.0.0/src/System.ComponentModel.Annotations/src/System/ComponentModel/DataAnnotations/EmailAddressAttribute.cs
