vb.net - Encode string to UTF-8

Question

I've made a class to encode a string

Public Class UTF8
    Public Shared Function encode(ByVal str As String)
        Dim utf8Encoding As New System.Text.UTF8Encoding
        Dim encodedString() As Byte

        encodedString = utf8Encoding.GetBytes(str)

        Return encodedString.ToString()
    End Function
End Class

Return encodedString.ToString() always returns "System.Byte[]". How could I get the real UTF-8 String?

Solution 1

Use UTF8.GetString(Byte[]) method.

Solution 2

We can check if a string is UTF-8 by examining the string BOM value. This is the correct code sample:

Public Shared Function encode(ByVal str As String) As String
    'supply True as the construction parameter to indicate
    'that you wanted the class to emit BOM (Byte Order Mark)
    'NOTE: this BOM value is the indicator of a UTF-8 string
    Dim utf8Encoding As New System.Text.UTF8Encoding(True)
    Dim encodedString() As Byte

    encodedString = utf8Encoding.GetBytes(str)

    Return utf8Encoding.GetString(encodedString)
End Function

Comments

[user1703401]

There's no point, that just returns the original string. A utf8 encoded string has to stay in a byte array.

[thom]

And how could I check if a string IS utf-8? Thank you.

[user1703401]

You missed the point. That's not possible, a string is always encoded in utf16 in .NET. If you think you got a string that contains utf8 then you surely do not, it is very likely to have gotten mangled in the process.

[htm11h]

@Hans your statement is incorrect, there are differenet .net encoding methods for UTF8, UTF16 and UTF32. msdn.microsoft.com/en-us/library/ms404377(v=vs.90).aspx Your comment should be deleted as inaccurate.

[Chris]

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