[英]Tag helper not being processed in ASP.NET Core 2
I've added the following tag helper:我添加了以下标签助手:
using System;
using System.Linq;
using Microsoft.AspNetCore.Mvc.ModelBinding;
using Microsoft.AspNetCore.Mvc.Rendering;
using Microsoft.AspNetCore.Mvc.TagHelpers;
using Microsoft.AspNetCore.Mvc.ViewFeatures;
using Microsoft.AspNetCore.Razor.TagHelpers;
namespace X.TagHelpers
{
[HtmlTargetElement(Attributes = ValidationForAttributeName + "," + ValidationErrorClassName)]
public class ValidationClassTagHelper : TagHelper
{
private const string ValidationForAttributeName = "k-validation-for";
private const string ValidationErrorClassName = "k-error-class";
[HtmlAttributeName(ValidationForAttributeName)]
public ModelExpression For { get; set; }
[HtmlAttributeName(ValidationErrorClassName)]
public string ValidationErrorClass { get; set; }
[HtmlAttributeNotBound]
[ViewContext]
public ViewContext ViewContext { get; set; }
public override void Process(TagHelperContext context, TagHelperOutput output)
{
Console.WriteLine("\n\n------------!!!!!!---------\n\n");
ModelStateEntry entry;
ViewContext.ViewData.ModelState.TryGetValue(For.Name, out entry);
if (entry == null || !entry.Errors.Any()) return;
var tagBuilder = new TagBuilder(context.TagName);
tagBuilder.AddCssClass(ValidationErrorClass);
output.MergeAttributes(tagBuilder);
}
}
}
and then in _ViewImports.cshtml
I've added the line:然后在
_ViewImports.cshtml
我添加了以下行:
@addTagHelper *, X.TagHelpers
The file is compiled correctly and if I introduce a syntax error dotnet build
warns me about it.该文件已正确编译,如果我引入语法错误
dotnet build
警告我。
Then in one of my pages I add:然后在我的其中一个页面中添加:
<div k-validation-for="OldPassword" k-error-class="has-danger"></div>
If I load the page I see no console output on the server side and the k-validation-for
and k-error-class
are forwarded to the generated page as is (as opposed to adding the has-danger
class to the class
attribute).如果我加载页面,我在服务器端看不到控制台输出,并且
k-validation-for
和k-error-class
将按原样转发到生成的页面(而不是将has-danger
类添加到class
属性) .
What am I doing wrong?我究竟做错了什么?
When registering Tag Helpers, it's the assembly that is required, not the namespace - explained in the docs .注册 Tag Helpers 时,需要的是程序集,而不是命名空间 - 在docs中进行了解释。
...the second parameter "Microsoft.AspNetCore.Mvc.TagHelpers" specifies the assembly containing the Tag Helpers.
...第二个参数“Microsoft.AspNetCore.Mvc.TagHelpers”指定包含标记帮助程序的程序集。 Microsoft.AspNetCore.Mvc.TagHelpers is the assembly for the built-in ASP.NET Core Tag Helpers.
Microsoft.AspNetCore.Mvc.TagHelpers 是内置 ASP.NET Core 标记帮助程序的程序集。
So in your case, you can just change this:所以在你的情况下,你可以改变这个:
@addTagHelper *, X.TagHelpers
To this:对此:
@addTagHelper *, X
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