Why ASCII numbers shows different characters in VB.Net and C#

Question

5.00/5 (1 vote)

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VB

Dim s(256) As String
Dim i As Integer
For i = 0 To 255
    s(i) = i & "=" & Chr(i)
Next
System.IO.File.WriteAllLines("AsciiVB.txt", s)

C#

string[] s = new string[256];
for (int i = 0; i <= 255; i++)
    s[i] = i.ToString() + "=" + ((char)i).ToString();
System.IO.File.WriteAllLines("AsciiCS.txt", s);

both programs Gives Different Outoputs from 128
ex.
VB

128=€

CS

128=

Posted 20-Nov-14 21:53pm

Sid_Joshi

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3 solutions

Solution 1

They are initialized with different locales. ASCII cover only the characters 0-127, all the others are extensions and depend on codepages.

More on http://en.wikipedia.org/wiki/Code_page[^].

Posted 20-Nov-14 22:14pm

den2k88

Solution 2

Please check the below links.

http://stackoverflow.com/questions/23562956/why-is-a-char-with-a-value-of-128-an-empty-string-and-not-a-euro-sign-%E2%82%AC[^]

Converting chars to ASCII in C#[^]

Posted 20-Nov-14 22:29pm

Mathew Soji

Updated 20-Nov-14 22:30pm

v2

Comments

Sid_Joshi 26-Nov-14 5:36am

Thanks for your answer...

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Daniele Rota Nodari · Accepted Answer · 2014-11-20T23:33:00

VB.NET Chr(i) and C# (char)i are not equivalent.

To obtain the same behavior, through VB.NET you have to call ChrW function instead of Chr function.

The first one (ChrW) accepts UNICODE values (between -32768 and 65535), whereas the second (Chr) accepts ASCII values (between 0 and 255).

Internally, ChrW always calls Convert.ToChar, the same as the explicit cast in C#.
Chr calls Convert.ToChar only when the value is between 0 and 127. For greater values it uses the Encoding object for ANSI code pages.

It is explained at Chr, ChrW Functions[^].

If you instead want to obtain in C# the same behavior from VB.NET, then you can:
1) In your C# project, add an assembly reference to Microsoft.VisualBasic, then replace

C#

(char)i

with

C#

Microsoft.VisualBasic.Strings.Chr(i)

.
2) You can emulate Microsoft.VisualBasic.Strings.Chr by replacing the cast with a call to Encoding.GetChars, as follows:

C#

var culture = System.Threading.Thread.CurrentThread.CurrentCulture;
var encoding = Encoding.GetEncoding(culture.TextInfo.ANSICodePage);
char[] buffer = new char[1];
for (int i = 0; i <= 255; i++)
{
    encoding.GetChars(new byte[] { (byte)i }, 0, 1, buffer, 0);
    s[i] = i.ToString() + "=" + buffer[0].ToString();
}

Note that Encoding is defined inside System.Text namespace.

Regards,
Daniele.