Compiler Error CS0840

 

Updated: July 20, 2015

For the latest documentation on Visual Studio 2017 RC, see Visual Studio 2017 RC Documentation.

'Property name' must declare a body because it is not marked abstract or extern. Automatically implemented properties must define both get and set accessors.

Unless a regular property is marked as abstract or extern, or is a member of a partial type, it must supply a body. Auto-implemented properties do not provide accessor bodies, but they must specify both accessors. To create a read-only auto-implemented property, make the set accessor private.

To correct this error

  1. Supply the missing body or accessor or else use the abstract, extern, or partial (Type) modifiers on it and/or its enclosing type.

The following example generates CS0840:

// cs0840.cs  
// Compile with /target:library  
using System;  
class Test  
{  
    public int myProp { get; } // CS0840  
  
    // to create a read-only property  
    // try the following line instead  
    public int myProp2 { get; private set; }  
  
}  

Auto-Implemented Properties

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