asp.net core mvc权限控制：在视图中控制操作权限

@if(HttpContext.User.HasClaim（"User","Delete"）)
{
<input type='button' value="删除"/>
}

<a asp-claim="goods,edit" asp-action="addgoods" asp-route-id="@goods.Id" class="btn-icon " title="编辑"><i class="icon-common-edit icon-pencil"></i></a>

class ClaimTagHelper:TagHelper
{
private const string ClaimAttributeName = "asp-claim";
    public ClaimTagHelper()
    {
    }
    [HtmlAttributeName(ClaimAttributeName)]
    public string Claim { get; set; }
}

[HtmlTargetElement("a", Attributes = ClaimAttributeName)]
  [HtmlTargetElement("button", Attributes = ClaimAttributeName)]
  [HtmlTargetElement("input", Attributes = ClaimAttributeName, TagStructure = TagStructure.WithoutEndTag)]
  public class ClaimTagHelper: TagHelper
{
......
}

public class ClaimTagHelper: TagHelper
{
.....

[HtmlAttributeNotBound]
    [ViewContext]
    public ViewContext ViewContext { get; set; } 
.....
}

public override void Process(TagHelperContext context, TagHelperOutput output)
    {
      if (string.IsNullOrEmpty(Claim))
      {
        return;
      }
      string[] claimData = Claim.Split(new char[] { '-' }, StringSplitOptions.RemoveEmptyEntries);
      if (claimData.Length == 1)
      {
        if (!ViewContext.HttpContext.User.HasClaim(m => m.Type == claimData[0]))
        {
          //无权限
          output.SuppressOutput();
        }
      }
      else
      {
        if (!ViewContext.HttpContext.User.HasClaim(m => m.Type == claimData[0] && m.Value == claimData[1]))
        {
          //无权限
          output.SuppressOutput();
        }
      }
}