如果我像这样创建一个EmailTagHelper:
public class EmailTagHelper : TagHelper
{
public string EmailAddress { get; set; }
public string Content { get; set; }
public override void Process(TagHelperContext context, TagHelperOutput output)
{
output.TagName = "a";
output.Attributes.SetAttribute("href", "mailto:" + this.EmailAddress);
output.Content.SetContent(this.Content);
}
}
我可以这样使用它:
<email content="Mail me!" email-address="hello@world.com"></email>
但是,我也可以这样做,而不会在Visual Studio中出现错误或编译错误:
<email content="Mail me - but where!?"></email>
有没有办法将属性标记为强制性,以便它们可以触发编译错误或至少在 Visual Studio 中触发红色波浪线,以便在运行时不会发生错误?
将所需的属性名称添加到HtmlTargetElement
:
[HtmlTargetElement("email", Attributes ="email-address")]
public class EmailTagHelper : TagHelper
{
public string EmailAddress { get; set; }
public string Content { get; set; }
public override void Process(TagHelperContext context, TagHelperOutput output)
{
// ...
}
}
此解决方案不会触发编译器错误或显示警告消息,但至少在您提供所需的属性之前,html 标记不会在编辑器中以绿色粗体呈现。
如果要在未提供属性时引发异常,则必须从HtmlTargetElement
属性中删除该异常:
[HtmlTargetElement("email")]
public class EmailTagHelper : TagHelper
{
public string EmailAddress { get; set; }
public string Content { get; set; }
public override void Process(TagHelperContext context, TagHelperOutput output)
{
if (string.IsNullOrWhiteSpace(EmailAddress))
throw new ArgumentNullException(nameof(EmailAddress));
// ...
}
}