Rails:如果表单返回验证错误,则保持 JSON 表单字段填充
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【中文标题】Rails:如果表单返回验证错误,则保持 JSON 表单字段填充【英文标题】:Rails: Keep JSON form fields populated if the form returns a validation error 【发布时间】:2021-01-28 15:51:01 【问题描述】:我有一个创建产品的 Rails 简单表单,我在表单中有以下三个字段,以便将产品与适当的类别相关联:
<div class="form-group">
<%= f.input :child_category_id, :collection => @categories.order(:name), :label_method => :name, :value_method => :id, label: "Category", :include_blank => "--Select Category--", input_html: id: "first_dropdown" %>
</div>
<div class="show_hide">
<%= f.input :subcategory_id, :collection => [] || @subcategory.order(:name), :label_method => :name, :value_method => :id, label: false, :include_blank => "--Select Category--", input_html: id: "second_dropdown" %>
</div>
<div class="show_hide_third">
<%= f.input :child_subcategory_id, :collection => [] || @child_subcategory.order(:name), :label_method => :name, :value_method => :id, label: false, input_html: id: "third_dropdown" %>
</div>
这是路线:
resources :products, :path => "products/select_item", only: [:select_item] do
get :select_item, on: :collection
end
这是我拥有的控制器内部的方法:
def select_item
if params[:child_category_id].present?
@subcategory = Subcategory.where(child_category_id: params[:child_category_id])
render :json => @subcategory.order(:name)
end
if params[:subcategory_id].present?
@child_subcategory = ChildSubcategory.where(subcategory_id: params[:subcategory_id])
render :json => @child_subcategory.order(:name)
end
end
这是我在控制器内部的新产品和创建产品方法:
def new; end
def create
@product = Product.new(product_params)
respond_to do |format|
if @product.save
format.html redirect_to root_path
format.json render :new, status: :created, location: @product
flash[:success] = "Product was successfully added."
else
format.html render :new
format.json render json: @product.errors, status: :unprocessable_entity
end
end
end
这是我用来根据所选值填充第二个和第三个字段的 javascript:
$('#first_dropdown').on('change', function()
$.ajax(
url: '/products/select_item/select_item?child_category_id=' + $(this).val(),
dataType: 'json',
success: function(data)
let childElement = $('#second_dropdown');
if( data.length === 0 )
$('.show_hide').hide();
$('.show_hide_third').hide();
else
$('.show_hide').show();
childElement.html('');
data.forEach(function(v)
let id = v.id;
let name = v.name;
childElement.append('<option value="' + id + '">' + name + '</option>');
);
);
);
$('#second_dropdown').on('change', function()
$.ajax(
url: '/products/select_item/select_item?subcategory_id=' + $(this).val(),
dataType: 'json',
success: function(data)
let childElement = $('#third_dropdown');
if( data.length === 0 )
$('.show_hide').hide();
$('.show_hide_third').hide();
else
$('.show_hide').show();
$('.show_hide_third').show();
childElement.html('');
data.forEach(function(v)
let id = v.id;
let name = v.name;
childElement.append('<option value="' + id + '">' + name + '</option>');
);
);
);
一切正常,所有字段都正确填充。我遇到的唯一问题是,当表单再次呈现时,由于验证错误,JSON 字段显示为空,即使它们已正确填充。即使表单返回验证错误,如何保持 JSON 表单字段填充?
【问题讨论】:
【参考方案1】:问题在于,在页面加载时,您的下拉列表中没有可供选择的选项;因此表单无法选择正确的值。你需要像这样更新你的控制器:
def create
@product = Product.new(product_params)
respond_to do |format|
if @product.save
format.html redirect_to root_path
format.json render :new, status: :created, location: @product
flash[:success] = "Product was successfully added."
else
@categories = Category.all.order(:name)
@subcategory = Subcategory.where(child_category_id: @product.child_category_id).order(:name)
@child_subcategory = ChildSubcategory.where(subcategory_id: @product.subcategory_id).order(:name)
format.html render :new
format.json render json: @product.errors, status: :unprocessable_entity
end
end
end
【讨论】:
感谢@TomDunning 的帮助......它工作得很好! :)))) 没问题,很高兴我能帮助@Dev :) @Dev 如果可以选择编辑,您可能希望在编辑和更新时使用相同的内容。 我刚刚对编辑和更新进行了更改....再次感谢!!以上是关于Rails:如果表单返回验证错误,则保持 JSON 表单字段填充的主要内容,如果未能解决你的问题,请参考以下文章
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