首页 \ 问答 \ 更改实例变量的方法是否属于我的Rails控制器或模型？(Does this method that changes an instance variable belong in my Rails controller or model?)

更改实例变量的方法是否属于我的Rails控制器或模型？(Does this method that changes an instance variable belong in my Rails controller or model?)

 关于控制器和实例变量，我有一个基本的“最佳实践”问题。  
 假设您在控制器中有新的实例变量或更新操作，是否可以通过控制器中的私有方法修改该实例变量？ 或者该方法是否存在于模型中？  
 例如，在下面的这个例子中，我需要循环实例变量的属性，并添加或删除一些东西。 例如，如果我使用3层深度的嵌套属性并且必须删除某些属性，请更改它们然后重新添加它们。我知道这可能看起来很奇怪，但是假设它是必要的。  
def new
  @some_thing = SomeThing.new(:some_params)
  do_something_to_inst_var # method call
  @some_thing.save
end

private

def do_something_to_inst_var
  @some_thing.addresses.each do |address|
    # modify it in some  way
  end
end
 
 或者这是不好的做法？ 这应该是模型中的方法，应该被称为：  
@some_thing.do_something_to_inst_var
 
 要么  
 我们应该将实例变量显式传递给方法，如：  
def new
  @some_thing = SomeThing.new(:some_params)
  do_something_to_inst_var(@some_thing) # method call
  @some_thing.save
end

private

def do_something_to_inst_var(some_thing)
  some_thing.addresses.each do |addresses|
    # modify it in some way
  end
end
 
 我在这里寻找一些清晰度，如果可能的话，举个例子。 我还在学习并试图改进，但我没有通过搜索找到答案。 

I have a basic "best practice" question about controllers and instance variables. 
Say you have an instance variable in anew or update action in a controller, is it ok to modify that instance variable via a private method in the controller? Or should the method exist in the model? 
e.g. in this example below, I need to loop through the attributes of an instance variable, and add or remove something. For example, if I am using nested attributes 3 layers deep and have to remove certain attributes, change them and then add them back in. I know this may seem strange, but assume it is necessary.  
def new
  @some_thing = SomeThing.new(:some_params)
  do_something_to_inst_var # method call
  @some_thing.save
end

private

def do_something_to_inst_var
  @some_thing.addresses.each do |address|
    # modify it in some  way
  end
end
 
Or is this bad practice? Should this be a method in the model and should be called like: 
@some_thing.do_something_to_inst_var
 
OR 
should we explicitly pass the instance variable to the method like: 
def new
  @some_thing = SomeThing.new(:some_params)
  do_something_to_inst_var(@some_thing) # method call
  @some_thing.save
end

private

def do_something_to_inst_var(some_thing)
  some_thing.addresses.each do |addresses|
    # modify it in some way
  end
end
 
I'm looking for some clarity here, with an example if possible. I'm still learning and trying to improve and I didn't find an answer by searching.

原文：https://stackoverflow.com/questions/37173619

更新时间：2023-12-08 15:12

最满意答案

 通用用户控件：  
 XAML：  
<UserControl x:Class="WpfControlLibrary.GenericUserControl"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
         xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:local="clr-namespace:WpfControlLibrary"
         mc:Ignorable="d" 
         d:DesignHeight="300" d:DesignWidth="300" x:Name="Control">
<UserControl.Resources>
    <Style TargetType="{x:Type local:GenericUserControl}">
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type local:GenericUserControl}">
                    <Grid Background="{Binding Background, ElementName=Control}">
                        <Grid.RowDefinitions>
                            <RowDefinition Height="5"></RowDefinition>
                            <RowDefinition Height="20"></RowDefinition>
                            <RowDefinition Height="*"></RowDefinition>
                            <RowDefinition Height="5"></RowDefinition>
                        </Grid.RowDefinitions>
                        <Grid.ColumnDefinitions>
                            <ColumnDefinition Width="5"/>
                            <ColumnDefinition Width="*"/>
                            <ColumnDefinition Width="5"/>
                        </Grid.ColumnDefinitions>
                        <TextBlock Grid.Column="1" Grid.Row="1" Text="{Binding Title, ElementName=Control}"/>
                        <ContentPresenter Grid.Column="1" Grid.Row="2"/>
                    </Grid>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
</UserControl.Resources>
 
 代码背后：  
namespace WpfControlLibrary
{
   public partial class GenericUserControl
   {
      public string Title
     {
        get { return (string)GetValue(TitleProperty); }
        set { SetValue(TitleProperty, value); }
     }

     public static readonly DependencyProperty TitleProperty =
      DependencyProperty.Register("Title", typeof(string), typeof(GenericUserControl), new PropertyMetadata(string.Empty));

public GenericUserControl()
     {
        InitializeComponent();
     }
   }
}
 
 而不是像这样使用用户控件：  
    <wpfControlLibrary:GenericUserControl Title="Other Title" Background="LightGray">
       <wpfControlLibrary:GenericUserControl Title="Yet Another Title" Background="Gray"/>
</wpfControlLibrary:GenericUserControl>

Generic usercontrol: 
XAML: 
<UserControl x:Class="WpfControlLibrary.GenericUserControl"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
         xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:local="clr-namespace:WpfControlLibrary"
         mc:Ignorable="d" 
         d:DesignHeight="300" d:DesignWidth="300" x:Name="Control">
<UserControl.Resources>
    <Style TargetType="{x:Type local:GenericUserControl}">
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type local:GenericUserControl}">
                    <Grid Background="{Binding Background, ElementName=Control}">
                        <Grid.RowDefinitions>
                            <RowDefinition Height="5"></RowDefinition>
                            <RowDefinition Height="20"></RowDefinition>
                            <RowDefinition Height="*"></RowDefinition>
                            <RowDefinition Height="5"></RowDefinition>
                        </Grid.RowDefinitions>
                        <Grid.ColumnDefinitions>
                            <ColumnDefinition Width="5"/>
                            <ColumnDefinition Width="*"/>
                            <ColumnDefinition Width="5"/>
                        </Grid.ColumnDefinitions>
                        <TextBlock Grid.Column="1" Grid.Row="1" Text="{Binding Title, ElementName=Control}"/>
                        <ContentPresenter Grid.Column="1" Grid.Row="2"/>
                    </Grid>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
</UserControl.Resources>
 
Code behind: 
namespace WpfControlLibrary
{
   public partial class GenericUserControl
   {
      public string Title
     {
        get { return (string)GetValue(TitleProperty); }
        set { SetValue(TitleProperty, value); }
     }

     public static readonly DependencyProperty TitleProperty =
      DependencyProperty.Register("Title", typeof(string), typeof(GenericUserControl), new PropertyMetadata(string.Empty));

public GenericUserControl()
     {
        InitializeComponent();
     }
   }
}
 
And than use the user control like this: 
    <wpfControlLibrary:GenericUserControl Title="Other Title" Background="LightGray">
       <wpfControlLibrary:GenericUserControl Title="Yet Another Title" Background="Gray"/>
</wpfControlLibrary:GenericUserControl>

更改实例变量的方法是否属于我的Rails控制器或模型？(Does this method that changes an instance variable belong in my Rails controller or model?)

最满意答案

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