使用has_many关联文章和类别的下拉列表：

Question

我正在创建一个脚手架 -

rails g scaffold Contact email:string email_provider:string

但我希望电子邮件提供商是一个下拉列表（使用gmail / yahoo / msn作为选项），而不是文本字段。我怎样才能做到这一点？

Answer 1

您可以查看the Rails documentation。无论如何，以你的形式：

  <%= f.collection_select :provider_id, Provider.order(:name),:id,:name, include_blank: true %>

您可以猜测，您应该预先定义另一个模型中的电子邮件提供商 - Provider，以便从中选择它们。

Answer 2

或自定义选项

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  libraries ptf77blas,ptcblas,atlas not found in C:\Python34\libs

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atlas_info:

  libraries f77blas,cblas,atlas not found in C:\Python34\lib

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  libraries f77blas,cblas,atlas not found in C:\

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  libraries f77blas,cblas,atlas not found in C:\Python34\libs

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lapack_info:

  libraries lapack not found in ['C:\\Python34\\lib', 'C:\\', 'C:\\Python34\\lib
s']

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lapack_src_info:

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running install

running build

running config_cc

unifing config_cc, config, build_clib, build_ext, build commands --compiler opti
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unifing config_fc, config, build_clib, build_ext, build commands --fcompiler opt
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running build_src

build_src

building py_modules sources

creating build

creating build\src.win-amd64-3.4

creating build\src.win-amd64-3.4\numpy

creating build\src.win-amd64-3.4\numpy\distutils

building library "npymath" sources

No module named 'numpy.distutils.msvccompiler' in numpy.distutils; trying from d
istutils

Running from numpy source directory.

C:\Users\JOOPED~1\AppData\Local\Temp\pip_build_Root\numpy\numpy\distutils\system
_info.py:1603: UserWarning:

    Atlas (http://math-atlas.sourceforge.net/) libraries not found.

    Directories to search for the libraries can be specified in the

    numpy/distutils/site.cfg file (section [atlas]) or by setting

    the ATLAS environment variable.

  warnings.warn(AtlasNotFoundError.__doc__)

C:\Users\JOOPED~1\AppData\Local\Temp\pip_build_Root\numpy\numpy\distutils\system
_info.py:1612: UserWarning:

    Blas (http://www.netlib.org/blas/) libraries not found.

    Directories to search for the libraries can be specified in the

    numpy/distutils/site.cfg file (section [blas]) or by setting

    the BLAS environment variable.

  warnings.warn(BlasNotFoundError.__doc__)

C:\Users\JOOPED~1\AppData\Local\Temp\pip_build_Root\numpy\numpy\distutils\system
_info.py:1615: UserWarning:

    Blas (http://www.netlib.org/blas/) sources not found.

    Directories to search for the sources can be specified in the

    numpy/distutils/site.cfg file (section [blas_src]) or by setting

    the BLAS_SRC environment variable.

  warnings.warn(BlasSrcNotFoundError.__doc__)

C:\Users\JOOPED~1\AppData\Local\Temp\pip_build_Root\numpy\numpy\distutils\system
_info.py:1505: UserWarning:

    Atlas (http://math-atlas.sourceforge.net/) libraries not found.

    Directories to search for the libraries can be specified in the

    numpy/distutils/site.cfg file (section [atlas]) or by setting

    the ATLAS environment variable.

  warnings.warn(AtlasNotFoundError.__doc__)

C:\Users\JOOPED~1\AppData\Local\Temp\pip_build_Root\numpy\numpy\distutils\system
_info.py:1516: UserWarning:

    Lapack (http://www.netlib.org/lapack/) libraries not found.

    Directories to search for the libraries can be specified in the

    numpy/distutils/site.cfg file (section [lapack]) or by setting

    the LAPACK environment variable.

  warnings.warn(LapackNotFoundError.__doc__)

C:\Users\JOOPED~1\AppData\Local\Temp\pip_build_Root\numpy\numpy\distutils\system
_info.py:1519: UserWarning:

    Lapack (http://www.netlib.org/lapack/) sources not found.

    Directories to search for the sources can be specified in the

    numpy/distutils/site.cfg file (section [lapack_src]) or by setting

    the LAPACK_SRC environment variable.

  warnings.warn(LapackSrcNotFoundError.__doc__)

C:\Python34\lib\distutils\dist.py:260: UserWarning: Unknown distribution option:
 'define_macros'

  warnings.warn(msg)

Traceback (most recent call last):

  File "", line 1, in 

  File "C:\Users\JOOPED~1\AppData\Local\Temp\pip_build_Root\numpy\setup.py", lin
e 251, in 

    setup_package()

  File "C:\Users\JOOPED~1\AppData\Local\Temp\pip_build_Root\numpy\setup.py", lin
e 243, in setup_package

    setup(**metadata)

  File "C:\Users\JOOPED~1\AppData\Local\Temp\pip_build_Root\numpy\numpy\distutil
s\core.py", line 169, in setup

    return old_setup(**new_attr)

  File "C:\Python34\lib\distutils\core.py", line 148, in setup

    dist.run_commands()

  File "C:\Python34\lib\distutils\dist.py", line 955, in run_commands

    self.run_command(cmd)

  File "C:\Python34\lib\distutils\dist.py", line 974, in run_command

    cmd_obj.run()

  File "C:\Users\JOOPED~1\AppData\Local\Temp\pip_build_Root\numpy\numpy\distutil
s\command\install.py", line 62, in run

    r = self.setuptools_run()

  File "C:\Users\JOOPED~1\AppData\Local\Temp\pip_build_Root\numpy\numpy\distutil
s\command\install.py", line 36, in setuptools_run

    return distutils_install.run(self)

  File "C:\Python34\lib\distutils\command\install.py", line 539, in run

    self.run_command('build')

  File "C:\Python34\lib\distutils\cmd.py", line 313, in run_command

    self.distribution.run_command(command)

  File "C:\Python34\lib\distutils\dist.py", line 974, in run_command

    cmd_obj.run()

  File "C:\Users\JOOPED~1\AppData\Local\Temp\pip_build_Root\numpy\numpy\distutil
s\command\build.py", line 39, in run

    old_build.run(self)

  File "C:\Python34\lib\distutils\command\build.py", line 126, in run

    self.run_command(cmd_name)

  File "C:\Python34\lib\distutils\cmd.py", line 313, in run_command

    self.distribution.run_command(command)

  File "C:\Python34\lib\distutils\dist.py", line 974, in run_command

    cmd_obj.run()

  File "C:\Users\JOOPED~1\AppData\Local\Temp\pip_build_Root\numpy\numpy\distutil
s\command\build_src.py", line 153, in run

    self.build_sources()

  File "C:\Users\JOOPED~1\AppData\Local\Temp\pip_build_Root\numpy\numpy\distutil
s\command\build_src.py", line 164, in build_sources

    self.build_library_sources(*libname_info)

  File "C:\Users\JOOPED~1\AppData\Local\Temp\pip_build_Root\numpy\numpy\distutil
s\command\build_src.py", line 299, in build_library_sources

    sources = self.generate_sources(sources, (lib_name, build_info))

  File "C:\Users\JOOPED~1\AppData\Local\Temp\pip_build_Root\numpy\numpy\distutil
s\command\build_src.py", line 386, in generate_sources

    source = func(extension, build_dir)

  File "numpy\core\setup.py", line 684, in get_mathlib_info

    st = config_cmd.try_link('int main(void) { return 0;}')

  File "C:\Python34\lib\distutils\command\config.py", line 243, in try_link

    self._check_compiler()

  File "C:\Users\JOOPED~1\AppData\Local\Temp\pip_build_Root\numpy\numpy\distutil
s\command\config.py", line 57, in _check_compiler

    self.compiler.initialize()

  File "C:\Python34\lib\distutils\msvc9compiler.py", line 371, in initialize

    vc_env = query_vcvarsall(VERSION, plat_spec)

  File "C:\Python34\lib\distutils\msvc9compiler.py", line 287, in query_vcvarsal
l

    raise ValueError(str(list(result.keys())))

ValueError: ['path']

Answer 3

您可以在Contact控制器中创建集合 -

app/controllers/contacts_controller.erb

添加

@providers = Provider.all.by_name

到新的，创建和编辑方法，使用by_name模型中Provider的范围 - app/models/provider.rb - 按名称排序

scope by_name  order(:name)

然后在视图中 - app/views/contacts/_form.html.erb - 您使用

<%= f.collection_select :provider_id, @providers, :id, :name, include_blank: true %>

对于rails表单，我还强烈建议您查看一个表单生成器，例如simple_form - https://github.com/plataformatec/simple_form - 这将完成所有繁重的工作。

Answer 4

这是一个漫长的过程，但如果你还没有实现，那么你最初可以用这种方式创建你的模型。以下方法描述了更改现有数据库。

1）为电子邮件提供商创建新模型：
$ rails g model provider name

2）这将使用名称字符串和时间戳创建模型。它还创建了我们需要添加到模式的迁移：
$ rake db:migrate

3）添加迁移以将提供者ID添加到联系人中：
$ rails g migration AddProviderRefToContacts provider:references

4）浏览迁移文件以检查它是否正常，并将其迁移：
$ rake db:migrate

5）好的，现在我们有了一个provider_id，我们不再需要原始的email_provider字符串了：
$ rails g migration RemoveEmailProviderFromContacts

6）在迁移文件中，添加如下所示的更改：

class RemoveEmailProviderFromContacts < ActiveRecord::Migration
  def change
    remove_column :contacts, :email_provider
  end
end

7）完成后，迁移更改：
$ rake db:migrate

8）让我们花点时间来更新我们的模型：
联系方式：belongs_to :provider
提供者：has_many :contacts

9）然后，我们在视图中的_form.html.erb partial中设置下拉逻辑：

  <div class="field">
    <%= f.label :provider %><br>
    <%= f.collection_select :provider_id, Provider.all, :id, :name %>
  </div>

10）最后，我们需要自己添加证明者。最好的方法是使用种子文件：

Provider.destroy_all

gmail = Provider.create!(name: "gmail")
yahoo = Provider.create!(name: "yahoo")
msn = Provider.create!(name: "msn")

$ rake db:seed

Answer 5

请查看here

您可以使用rails标记或使用纯HTML标记

Rails标记

<%= select("Contact", "email_provider", Contact::PROVIDERS, {:include_blank => true}) %>

* 以上代码行将成为HTML代码（HTML代码），在下面找到*

HTML标记

<select name="Contact[email_provider]">
  <option></option>
  <option>yahoo</option>
  <option>gmail</option>
  <option>msn</option>
</select>

Answer 6

在你的模特中，

class Contact
  self.email_providers = %w[Gmail Yahoo MSN]
  validates :email_provider, :inclusion => email_providers
end

在您的表单中，

<%= f.select :email_provider, 
    options_for_select(Contact.email_providers, @contact.email_provider) %>

options_for_select的第二个arg将选择任何当前的email_provider。

Answer 7

使用has_many关联文章和类别的下拉列表：

has_many :articles

belongs_to :category

<%= form.select :category_id,Category.all.pluck(:name,:id),{prompt:'select'},{class: "form-control"}%>

Answer 8

<%= f.select :email_provider, ["gmail","yahoo","msn"]%>

如何在rails表格中下拉<select>字段？</select>

8 个答案:

使用has_many关联文章和类别的下拉列表：