c# - 强制开发人员使用特定的构造函数

Question

我有以下类(class)

  public class UIControl
  {
    public string FName{ get; set; }
    public HtmlInputCheckBox SelectCheckBox { get; set; }
    public bool OverrideSelect { get; set; }

    //Want to throw an ApplicationExceptioh if developer uses this constructor and passes
    //chkSelect = null
    public UIControl(string sFieldName, HtmlInputCheckBox chkSelect)
    {
      this.FName= sFieldName;
      this.SelectCheckBox = chkSelect;
    }

    public UIControl(string sFieldName, HtmlInputCheckBox chkSelect, bool overrideSelect)
      : this(sFieldName, chkSelect)
    {
      OverrideSelect = overrideSelect;
    }
  }

我想确保开发人员仅在 chkSelect 不为 null 时才使用第一个构造函数。

我想做一个:

throw new ApplicationException("Dev is using the incorrect constructor");

Answer 1

您可以这样使用私有(private)构造函数:

public UIControl(string sFieldName, HtmlInputCheckBox chkSelect) 
    : this(sFieldName, chkSelect, false, false)
{      
}    

public UIControl(string sFieldName, HtmlInputCheckBox chkSelect, 
     bool overrideSelect)      
    : this(sFieldName, chkSelect, overrideSelect, true)    
{      
}  

private UIControl(string sFieldName, HtmlInputCheckBox chkSelect, 
   bool overrideSelect, bool allowOverride)      
{      
    if ((!allowOverride) && (chkSelect == null)) 
         throw new ArgumentException(...);
    this.FName= sFieldName;      
    this.SelectCheckBox = chkSelect;    
    OverrideSelect = overrideSelect;    
}  

有很多变体，但作为一般规则，不太具体的构造函数会调用更具体的构造函数。例如，以下内容也适用于您的情况:

public UIControl(string sFieldName, HtmlInputCheckBox chkSelect)    
    : this(sFieldName, chkSelect, false)
{      
   if (chkSelect == null) throw ...
}    

public UIControl(string sFieldName, HtmlInputCheckBox chkSelect, 
     bool overrideSelect)    
{      
    this.FName= sFieldName;      
    this.SelectCheckBox = chkSelect;    
    this.OverrideSelect = overrideSelect;    
}