‫توصیف فیلدها توسط Tag Helper و Data annotation

public class Student{ [Display(Name="نام خانوادگی")] public string FamilyName { get; set;}
}

<label asp-for="FamilyName"></label>

[Display( Name = "نام خانوادگی", Description = "بهتر است فقط در اینجا نام خانوادگی شخص وارد شود")]
public string FamilyName{ get; set; }

<span asp-description-for="FamilyName"></span>

<span>بهتر است فقط در اینجا نام خانوادگی شخص وارد شود</span>

using Microsoft.AspNetCore.Mvc.Rendering;
using Microsoft.AspNetCore.Mvc.ViewFeatures;
using Microsoft.AspNetCore.Razor.TagHelpers;
[HtmlTargetElement("div", Attributes = ForAttributeName)]
[HtmlTargetElement("p", Attributes = ForAttributeName)]
[HtmlTargetElement("span", Attributes = ForAttributeName)]
public sealed class DescriptionForTagHelper : TagHelper
{ private const string ForAttributeName = "asp-description-for"; [HtmlAttributeName(ForAttributeName)] public ModelExpression For { get; set; } = default!; public override async Task ProcessAsync(TagHelperContext context, TagHelperOutput output) { if (context == null) { throw new ArgumentNullException(nameof(context)); } if (output == null) { throw new ArgumentNullException(nameof(output)); } var description = For.Metadata.Description; if (description != null) { // Do not update the content if another tag helper // targeting this element has already done so. if (!output.IsContentModified) { var childContent = await output.GetChildContentAsync(); if (childContent.IsEmptyOrWhiteSpace) { output.Content.SetHtmlContent(description); } else { output.Content.SetHtmlContent(childContent); } } } }
}