Nullable Types & Null Operators - CSharp Language Basics

CSharp examples for Language Basics:Nullable

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Introduction

Nullable types work well with the ?? operator.

For example:

Demo Code

using System;/* w  ww .  ja  v a2s. co  m*/
class Test
{
   static void Main()
   {
      int? x = null;
      int y = x ?? 5;        // y is 5
      int? a = null, b = 1, c = 2;
      Console.WriteLine (a ?? b ?? c);  // 1 (first non-null value)
   }
}

Result

In the following example, length evaluates to null: 

System.Text.StringBuilder sb = null;
int? length = sb?.ToString().Length;

We can combine this with the null-coalescing operator to evaluate to zero instead of null: 

int length = sb?.ToString().Length ?? 0;  // Evaluates to 0 if sb is null

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