asp.net 核心中的自定义标签助手和不显眼的验证

Question

我通过从数据库中提取有关表单字段的元数据，使用 TagHelper 类动态生成表单元素。我通过生成执行验证所需的所有属性添加了不显眼的验证，例如 data-val-required 属性等（请检查函数 ValidationAnnotation()）。通常，这些属性是通过数据注释以标准方式添加到 MVC 中的，方法是根据需要标记字段。如果我不能使用数据注释，因为所有字段都是从数据库中提取的。是否有其他标准方法可以为这种情况添加不显眼的验证？

 public class CustomAttributeTagHelper : TagHelper
    {
        private readonly ISchemaService _schemaService;
        public Dictionary<string, object> CustomUserInfo { get; set; }
        public CustomAttributeTagHelper (
            ISchemaService schemaService
            )
        {
            _schemaService = schemaService;
        }

        public override async Task ProcessAsync(TagHelperContext context, TagHelperOutput output)
        {
            var userSchemasResponse = await _schemaService.GetUserSchema();
            if (userSchemasResponse.Success)
            {
                output.Content.AppendHtml("<div>");
                output.Content.AppendHtml("<div>");
                foreach (var userSchema in userSchemasResponse.UserSchemas)
                {
                    //validation data annotation
                    string validationAnnotationMessage = string.Empty, validationAnnotationInput = string.Empty;
                    if (userSchema.IsRequiredField)
                    {
                        (validationAnnotationMessage, validationAnnotationInput) = ValidationAnnotation(userSchema);
                    }

                    if (userSchema.Type == "string")
                    {  
                        output.Content.AppendHtml("<div>");
                        string value = string.Empty;
                        if (CustomUserInfo.ContainsKey(userSchema.PropertyName))
                        {
                            value = CustomUserInfo[userSchema.PropertyName].ToString();
                        }
                        output.Content.AppendHtml(
                            $"<Label for= {userSchema.PropertyName}> {userSchema.Title} </Label>");
                        if (userSchema.CustomEnums.Count > 0)
                        {
                            output.Content.AppendHtml(
                                $"<select {validationAnnotationInput} for= '{userSchema.PropertyName}' Id='{userSchema.PropertyName}' name='{userSchema.PropertyName}' >");
                            foreach (var custEnum in userSchema.CustomEnums)
                            {
                                output.Content
                                    .AppendHtml($"<option value='' selected>Please Select</option>");
                                if (value != null && value.Equals(custEnum.Value, StringComparison.OrdinalIgnoreCase))
                                {
                                    output.Content
                                        .AppendHtml($"<option value='{custEnum.Key}' selected>{custEnum.Value}</option>");
                                }
                                else
                                {
                                    output.Content
                                        .AppendHtml($"<option value='{custEnum.Key}' >{custEnum.Value}</option>");
                                }
                            }

                            output.Content.AppendHtml($"</select>");
                        }
                        else
                        {


                            output.Content.AppendHtml(
                                $"<Input {validationAnnotationInput} for= '{userSchema.PropertyName}' Id='{userSchema.PropertyName}' name='{userSchema.PropertyName}' value='{value}'/>");
                               output.Content.AppendHtml($"<span   />");

                        }

                        output.Content.AppendHtml($"<span {validationAnnotationMessage}  ></span>");
                        output.Content.AppendHtml("</div>");
                    }

                    if (userSchema.Type == "boolean")
                    {
                        bool value = false;
                        if (CustomUserInfo.ContainsKey(userSchema.PropertyName))
                        {
                            value = Convert.ToBoolean(CustomUserInfo[userSchema.PropertyName].ToString());
                        }
                        output.Content.AppendHtml("<div>");
                        output.Content.AppendHtml(
                            $"<Label for= {userSchema.PropertyName}> {userSchema.Title} </Label>");
                        output.Content.AppendHtml("<div>");
                        if (value)
                        {
                            output.Content.AppendHtml(
                                $"<Input type='radio' checked={true}   for= {userSchema.PropertyName} Id={userSchema.PropertyName} name={userSchema.PropertyName} > Yes");
                            output.Content.AppendHtml(
                                $"<Input type='radio'  for= {userSchema.PropertyName} Id={userSchema.PropertyName} name={userSchema.PropertyName} > No");
                        }
                        else
                        {
                            output.Content.AppendHtml(
                                $"<Input type='radio'    for= {userSchema.PropertyName} Id={userSchema.PropertyName} name={userSchema.PropertyName} > Yes");
                            output.Content.AppendHtml(
                                $"<Input type='radio' checked={false}  for= {userSchema.PropertyName} Id={userSchema.PropertyName} name={userSchema.PropertyName} > No");
                        }
                        output.Content.AppendHtml("</div>");
                        //output.Content.AppendHtml($"<span asp-validation-for={userSchema.PropertyName}  />");
                        output.Content.AppendHtml("</div>");
                    }




                }
                output.Content.AppendHtml("</div>");
                output.Content.AppendHtml("</div>");
            }

        }
//validation data annotation
        private Tuple<string , string > ValidationAnnotation(
            UserSchema userSchema)
        {
            var validationAnnotationMessage =
                $"data-valmsg-replace=true data-valmsg-for='{userSchema.PropertyName}' class='field-validation-valid'";
            var validationAnnotationInput = $"data-val=true data-val-required='{userSchema.Title} is required'";
            return new Tuple<string, string>(validationAnnotationMessage, validationAnnotationInput);

        }
    }

页面生成：

Answer 1

我将您的代码简化为下面，它可以在不显眼的验证下正常工作。

1. CustomAttributeTagHelper

   public class CustomAttributeTagHelper : TagHelper
   {
       public override async Task ProcessAsync(TagHelperContext context, TagHelperOutput output)
       {
           output.Content.AppendHtml("<div>");
           string validationAnnotationMessage = string.Empty, validationAnnotationInput = string.Empty;
           UserSchema userSchema = new UserSchema { PropertyName = "Title" , Title = "Title", Type = "string"};
           (validationAnnotationMessage, validationAnnotationInput) = ValidationAnnotation(userSchema);
   
           if (userSchema.Type == "string")
           {
               output.Content.AppendHtml("<div>");
               string value = string.Empty;
   
               output.Content.AppendHtml(
                   $"<Label for= {userSchema.PropertyName}> {userSchema.Title} </Label>");
               output.Content.AppendHtml(
                   $"<Input {validationAnnotationInput} for= '{userSchema.PropertyName}' Id='{userSchema.PropertyName}' name='{userSchema.PropertyName}' value='{value}'/>");
               output.Content.AppendHtml($"<span   />");
   
               output.Content.AppendHtml($"<span {validationAnnotationMessage}  ></span>");
               output.Content.AppendHtml("</div>");
           }
           output.Content.AppendHtml("</div>");
       }
       private Tuple<string, string> ValidationAnnotation(
       UserSchema userSchema)
       {
           var validationAnnotationMessage =
               $"data-valmsg-replace=true data-valmsg-for='{userSchema.PropertyName}' class='field-validation-valid'";
           var validationAnnotationInput = $"data-val=true data-val-required='{userSchema.Title} is required'";
           return new Tuple<string, string>(validationAnnotationMessage, validationAnnotationInput);
   
       }
   }
   

2. 查看

   <div class="row">
       <div class="col-md-4">
           <form asp-action="Create">
               <div asp-validation-summary="ModelOnly" class="text-danger"></div>
               <custom-attribute></custom-attribute>
               <div class="form-group">
                   <label asp-for="Title" class="control-label"></label>
                   <input asp-for="Title" class="form-control" />
                   <span asp-validation-for="Title" class="text-danger"></span>
               </div>
   
               <div class="form-group">
                   <input type="submit" value="Create" class="btn btn-primary" />
               </div>
           </form>
       </div>
   </div>
   
   @section Scripts {
       @{await Html.RenderPartialAsync("_ValidationScriptsPartial");}
   }
   

注意

检查此代码@{await Html.RenderPartialAsync("_ValidationScriptsPartial");}是否在您的视图中。