您可以在標(biāo)簽助手中自定義一個(gè)CreateOrMergeAttribute方法，并首先將新的 css 類添加到屬性列表中。像下面這樣：
public class EmailTagHelper: TagHelper
{
private const string EmailDomain = "contoso.com";
// Can be passed via <email mail-to="..." />.
// PascalCase gets translated into kebab-case.
public string MailTo { get; set; }
public override void Process(TagHelperContext context, TagHelperOutput output)
{
output.TagName = "a"; // Replaces <email> with <a> tag
var address = MailTo + "@" + EmailDomain;
output.Attributes.SetAttribute("href", "mailto:" + address);
output.Content.SetContent(address);
CreateOrMergeAttribute("class", "test", output);
}
private void CreateOrMergeAttribute(string name, object content, TagHelperOutput output)
{
var currentAttribute = output.Attributes.FirstOrDefault(attribute => attribute.Name == name);
if (currentAttribute == null)
{
var attribute = new TagHelperAttribute(name, content);
output.Attributes.Add(attribute);
}
else
{
var newAttribute = new TagHelperAttribute(
name,
$"{currentAttribute.Value.ToString()} {content.ToString()}",
currentAttribute.ValueStyle);
output.Attributes.Remove(currentAttribute);
output.Attributes.Add(newAttribute);
}
}
}
結(jié)果截圖：
