如何确保所有类字段在首次使用之前都已初始化 [英] How to ensure all class fields have been initialized before first use

问题描述

比方说，我有一个可以进行一些计算的类.这组计算需要输入一组参数.

let's say I have a class that does some calculations. This set of calculations requires as an input a set of parameters.

public class Calculator
{
private CalculatorConfig _config;
public Calculator(CalculatorConfig config)
{
_config = config;
}

public Result Calculate(object obj){}
}

我的CalculatorConfig类非常简单:

My CalculatorConfig class is very simple :

public class CalculatorConfig
{
      public double param1;
      public double param2;
      ...
}

我非常简单地初始化它

var config = new CalculatorConfig();
config.param1 = val;
....
var calculator = new Calculator(config);

我遇到的难题是，此类的用户可能会忘记初始化一些可能导致奇怪行为的字段. 可能有意义的解决方案是将字段转换为属性，并且对于每个私有字段，都有一个额外的布尔值，该布尔值将保存有关字段是否已初始化的信息. 我还可以创建一个大型构造函数，该构造函数会将所有字段作为参数.

The dilema I have is that user of this class may forget to initialize some of the fields which may lead to weird behaviour. Solution that may make a sense would be to convert fields into properties and for each private field have an extra boolean that would hold the information whether the field was initialized. I can also create a megaconstructor, that would have all the fields as arguments.

在这种情况下，您会选择哪种方法?

What approach would you choose in this case?

谢谢

推荐答案

我将使用另一种方法.

• 将另一个称为Check的方法(也许是内部方法)添加到您的CalculatorConfig类.
• 在Calculate方法的执行过程中调用此方法.

• 在Check方法中，验证每个参数并抛出自定义 异常是有问题的

• Add another method (perhaps an internal method) called Check to your CalculatorConfig class.
• Call this method inside the execution of the Calculate method.

• In the Check method verify each parameter and throw a custom exception is something is wrong

public class CalculatorConfig 
{ 
  public double param1; 
  public double param2; 
  ... 
  internal void Check()
  {
       if(param1 == 0.0)
           throw new ArgumentException("Configuration error: param1 is not valid!");
       if(param2 == 0.0)
           throw new ArgumentException("Configuration error: param2 is not valid!");
       .... // other internal checks
  }
} 


public class Calculator 
{ 
    private CalculatorConfig _config; 
    public Calculator(CalculatorConfig config) 
    { 
        _config = config; 
    } 

    public Result Calculate(object obj)
    {
        // Throw ArgumentException if the configuration is not valid
        // Will be responsability of our caller to catch the exception
        _config.Check();

        // Do your calcs
        .....
    } 
} 

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