A field initializer cannot reference the nonstatic field method or property

Question

I have a class and when I try to use it in another class I receive the error below    using System  using System Collections Generic  using System Linq   namespace MySite       public class Reminders               public Dictionary lt TimeSpan  string gt  TimeSpanText   get  set                We are setting the default values using the Costructor         public Reminders                         TimeSpanText Add TimeSpan Zero   None                TimeSpanText Add new TimeSpan 0  0  5  0    5 minutes before                TimeSpanText Add new TimeSpan 0  0  15  0    15 minutes before                TimeSpanText Add new TimeSpan 0  0  30  0    30 minutes before                TimeSpanText Add new TimeSpan 0  1  0  0    1 hour before                TimeSpanText Add new TimeSpan 0  2  0  0    2 hours before                TimeSpanText Add new TimeSpan 1  0  0  0    1 day before                TimeSpanText Add new TimeSpan 2  0  0  0    2 day before                         Using the class in another class   class SomeOtherClass         private Reminders reminder   new Reminders           error happens on this line      private dynamic defaultReminder   reminder TimeSpanText TimeSpan FromMinutes 15                Error  CS0236    A field initializer cannot reference the nonstatic field  method  or property   Why does it happen and how to fix it

User · Answer

You need to put that code into the constructor of your class:

private Reminders reminder = new Reminders();
private dynamic defaultReminder;

public YourClass()
{
    defaultReminder = reminder.TimeSpanText[TimeSpan.FromMinutes(15)];
}

The reason is that you can't use one instance variable to initialize another one using a field initializer.

User · Answer

private dynamic defaultReminder   reminder TimeSpanText TimeSpan FromMinutes 15    is a field initializer and executes first  before any field without an initializer is set to its default value and before the invoked instance constructor is executed   Instance fields that have no initializer will only have a legal  default  value after all instance field initializers are completed  Due to the initialization order  instance constructors are executed last  which is why the instance is not created yet the moment the initializers are executed  Therefore the compiler cannot allow any instance property  or field  to be referenced before the class instance is fully constructed  This is because any access to an instance variable like reminder implicitly references the instance  this  to tell the compiler the concrete memory location of the instance to use   This is also the reason why this is not allowed in an instance field initializer       A variable initializer for an instance field cannot reference the   instance being created  Thus  it is a compile-time error to reference   this in a variable initializer  as it is a compile-time error for a   variable initializer to reference any instance member through a   simple name    The only type members that are guaranteed to be initialized before instance field initializers are executed are class  static  field initializers and class  static  constructors and class methods  Since static members are instance independent  they can be referenced at any time   class SomeOtherClass     private static Reminders reminder   new Reminders          This operation is allowed       since the compiler can guarantee that the referenced class member is already initialized      when this instance field initializer executes   private dynamic defaultReminder   reminder TimeSpanText TimeSpan FromMinutes 15        That s why instance field initializers are only allowed to reference a class member  static member   This compiler initialization rules will ensure a deterministic type instantiation     For more details I recommend this document  Microsoft Docs  Class declarations   This means that an instance field that references another instance member to initialize its value  must be initialized from the instance constructor or the referenced member must be declared static

User · Answer

This line   private dynamic defaultReminder                              reminder TimeSpanText TimeSpan FromMinutes 15      You cannot use an instance variable to initialize another instance variable  Why  Because the compiler can rearrange these - there is no guarantee that reminder will be initialized before defaultReminder  so the above line might throw a NullReferenceException   Instead  just use   private dynamic defaultReminder   TimeSpan FromMinutes 15     Alternatively  set up the value in the constructor   private dynamic defaultReminder   public Reminders         defaultReminder   reminder TimeSpanText TimeSpan FromMinutes 15         There are more details about this compiler error on MSDN - Compiler Error CS0236

User · Answer

you can use like this  private dynamic defaultReminder   gt  reminder TimeSpanText TimeSpan FromMinutes 15

[c#] A field initializer cannot reference the nonstatic field, method, or property

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