Question

How can my strings have different hash codes but the same text value of “16 777 216”?

The test method does not pass:

using System;
using System.Text;
using System.Collections.Generic;
using System.Linq;
using Microsoft.VisualStudio.TestTools.UnitTesting;

namespace UnitTestStringEquals
{
  [TestClass]
  public class FormatterTests
  {
    [TestMethod]
    public void Double_Test_1()
    {
      Assert.AreEqual("16 777 216", FormatDoubleWithThousandSeparator(16777216, 0));
    }

    public string FormatDoubleWithThousandSeparator(double value, int digits)
    {
      double result = Math.Round((double)value, digits);

      System.Globalization.NumberFormatInfo nfi = (System.Globalization.NumberFormatInfo)System.Globalization.NumberFormatInfo.InvariantInfo.Clone();
      nfi.NumberGroupSeparator = " ";

      return result.ToString("###,###,###,###,###,###,##0.#####", nfi);
    }
  }
}

Answer 1

Because the two strings are not the same object, thus they are not equal, there is a string comparision method that should be used instead.

Make sure this isn’t the case one string has a non-printing character and the other one does not. You have to remember that a string is an object. So you need to compare the value of said object to the value of another object.

http://msdn.microsoft.com/en-us/library/system.string.equals.aspx
http://msdn.microsoft.com/en-us/library/1hkt4325.aspx