vb.NET Tutorial: String to charArray to String gives unexpected result. Bug?

Question

I am following online tutorials re-learning Visual Basic as incarnated in Visual Studio 2015. The tutorials are very boring, but I'm going through them anyway in case a gem or two might be hiding in them. In one tutorial, we create a String, convert it to a CharArray, reverse the array, then print it out to the console one character at a time. All good. Then I decided to just convert the array back to a String and use WriteLine, for kicks...

Module Module1

Sub Main()

    Dim myText As String = "Hey, this is a string!"
    Console.WriteLine(myText)

    Dim myCharArray() As Char = myText.ToCharArray()
    Array.Reverse(myCharArray)

    Dim reversedText As String = myCharArray.ToString()
    Console.WriteLine(reversedText)

    ' Console output is:

    ' Hey, this is a string!
    ' System.char[]

    ' Even less intuitive, for me, this:
    Console.WriteLine(myCharArray)
    ' produces this:

    ' !gnirts a si siht ,yeH

    ' in the console. While this:
    Console.WriteLine(myCharArray.ToString())
    ' gives System.char[] again.

    Console.ReadLine()

End Sub

End Module

Obviously, WriteLine has no issue with writing out an array of characters. My question is why it prints the String conversion of a character array as System.char[], even when that conversion is explicitly assigned to an object of type String, when it has no problem printing other String objects as their actual string representation.

I realize this is a trivial and stupid thing to ask about, but if there is an underlying cause that knowledge of will help me avoid a bug or two, I would like to know it.

To convert char array to string, you should pass it as parameter to string constructor. — Reza Aghaei
– Reza Aghaei, Commented Jan 8, 2016 at 3:59
That makes sense. I only used to .toString() method of CharArray because it came up in intellisense as one of the methods available to tinker with. I assume by your response that .toString() doesn't actually convert it to a String? While .toCharArray does convert a String to a CharArray? — Hippo Potamus
– Hippo Potamus, Commented Jan 8, 2016 at 4:02
Infact, ToString converts the Char[] to a string, string representation of type name. But you need to convert it to the string created from characters in the array. — Reza Aghaei
– Reza Aghaei, Commented Jan 8, 2016 at 4:07
Alexei Levenkov cleared it up for me in an answer below. Good note to file away for the future. Thanks for your help. — Hippo Potamus
– Hippo Potamus, Commented Jan 8, 2016 at 4:08

Alexei Levenkov · Accepted Answer · 2016-01-08 04:05:48Z

4

myCharArray.ToString() calls Array.ToString() that uses default implementation of Object.ToString which simply returns type name.

You want to construct string from character array instead - String(Char[])

Dim reversedText As New String(myCharArray)

edited Jan 8, 2016 at 4:05

answered Jan 8, 2016 at 4:03

Alexei Levenkov

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1 Comment

Hippo Potamus Over a year ago

Thank you. That is the piece of the puzzle I was missing. The other answers/comments gave the correct implementation. The why is what I wasn't getting.

Reza Aghaei · Accepted Answer · 2016-01-08 04:10:33Z

1

To convert char array to string, you should pass it as parameter to string constructor.

Dim str = "This is a string!"
Console.WriteLine(str) ' This is a string!
Console.WriteLine(str.ToCharArray().ToString()) ' System.Char[]
Console.WriteLine(New String(str.ToCharArray())) ' This is a string!

Infact, ToString converts the Char[] to a String; but string representation of type name, while you need to convert Char[] to a string created from characters in the array.

edited Jan 8, 2016 at 4:10

answered Jan 8, 2016 at 4:02

Reza Aghaei

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