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Another bug
Apperantely I've discovered a bug in .NET where two identical strings are compared through object reference.
Consider the following code:
using
System;using
System.Collections;using
System.Collections.Specialized;using
System.Reflection;namespace
test2{
class Class1
{
[STAThread]
static void Main(string[] args)
{
ReallyStrangeBug();
}
public static void ReallyStrangeBug()
{
HybridDictionary dic = new HybridDictionary();
foreach(MemberInfo member in typeof(object).GetMembers(BindingFlags.Public | BindingFlags.Instance))
dic.Add(member.Name,member);
Console.WriteLine("Using Objects comparision:");
Console.WriteLine(objectExistIn("ToString",dic.Keys));
Console.WriteLine("Using strings comparision:");
Console.WriteLine(stringExistIn("ToString",dic.Keys));
Console.WriteLine(dic.Contains("ToString"));
}
private static bool objectExistIn(object o, IEnumerable enumerable)
{
foreach(object current in enumerable)
{
Console.WriteLine("'{0}' == '{1}': {2}",o,current,o==current);
if(o==current)
return true;
}
return false;
}
private static bool stringExistIn(string o, IEnumerable enumerable)
{
foreach(string current in enumerable)
{
Console.WriteLine("'{0}' == '{1}': {2}",o,current,o==current);
if(o==current)
return true;
}
return false;
}
}
}
This produce the following output:
Using Objects comparision:
'ToString' == 'GetHashCode': False
'ToString' == 'Equals': False
'ToString' == 'ToString': False
'ToString' == 'GetType': False
'ToString' == '.ctor': False
False
Using strings comparision:
'ToString' == 'GetHashCode': False
'ToString' == 'Equals': False
'ToString' == 'ToString': True
True
True
Press any key to continue
Reason unknown
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