C# 转 VB.net代码

Question

    private void button1_Click(object sender, EventArgs e)
    {

        textBox1.Text = System.IO.File.ReadAllText(@textBox2.Text , Encoding.GetEncoding("UTF-8")); //gb2312



        string fileName = @textBox2.Text ;
        Encoding encoding = GetTextFileEncodingType(fileName);
        Console.WriteLine(encoding.GetType());
        Console.WriteLine($"代码页:【{encoding.CodePage}】，描述【{encoding.EncodingName}】");
        Console.WriteLine($"WindowsCodePage:【{encoding.WindowsCodePage}】,WebName:【{encoding.WebName}】,HeaderName:【{encoding.HeaderName}】,BodyName:【{encoding.BodyName}】");
        Console.ReadLine();


    }
}
















    /// 

    /// 获取文本文件的字符编码类型
    /// 
    /// <param name="fileName"></param>
    /// <returns></returns>
    static Encoding GetTextFileEncodingType(string fileName)
    {
        Encoding encoding = Encoding.Default;
        FileStream fileStream = new FileStream(fileName, FileMode.Open, FileAccess.Read);
        BinaryReader binaryReader = new BinaryReader(fileStream, encoding);
        byte[] buffer = binaryReader.ReadBytes((int)fileStream.Length);
        binaryReader.Close();
        fileStream.Close();
        if (buffer.Length >= 3 && buffer[0] == 239 && buffer[1] == 187 && buffer[2] == 191)
        {
            encoding = Encoding.UTF8;
        }
        else if (buffer.Length >= 3 && buffer[0] == 254 && buffer[1] == 255 && buffer[2] == 0)
        {
            encoding = Encoding.BigEndianUnicode;
        }
        else if (buffer.Length >= 3 && buffer[0] == 255 && buffer[1] == 254 && buffer[2] == 65)
        {
            encoding = Encoding.Unicode;
        }
        else if (IsUTF8Bytes(buffer))
        {
            encoding = Encoding.UTF8;
        }
        return encoding;
    }

    /// 

    /// 判断是否是不带 BOM 的 UTF8 格式
    /// BOM（Byte Order Mark），字节顺序标记，出现在文本文件头部，Unicode编码标准中用于标识文件是采用哪种格式的编码。
    /// 
    /// <param name="data"></param>
    /// <returns></returns>
    private static bool IsUTF8Bytes(byte[] data)
    {
        int charByteCounter = 1; //计算当前正分析的字符应还有的字节数 
        byte curByte; //当前分析的字节. 
        for (int i = 0; i < data.Length; i++)
        {
            curByte = data[i];
            if (charByteCounter == 1)
            {
                if (curByte >= 0x80)
                {
                    //判断当前 
                    while (((curByte <<= 1) & 0x80) != 0)
                    {
                        charByteCounter++;
                    }
                    //标记位首位若为非0 则至少以2个1开始 如:110XXXXX...........1111110X 
                    if (charByteCounter == 1 || charByteCounter > 6)
                    {
                        return false;
                    }
                }
            }
            else
            {
                //若是UTF-8 此时第一位必须为1 
                if ((curByte & 0xC0) != 0x80)
                {
                    return false;
                }
                charByteCounter--;
            }
        }
        if (charByteCounter > 1)
        {
            throw new Exception("非预期的byte格式");
        }
        return true;
    }

Answer 1

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
TextBox1.Text = System.IO.File.ReadAllText(TextBox2.Text, Encoding.GetEncoding("UTF-8")) 'gb2312
Dim fileName As String = TextBox2.Text
Dim encoding As Encoding = GetTextFileEncodingType(fileName)
Console.WriteLine(encoding.GetType())
Console.WriteLine($"代码页:【{encoding.CodePage}】，描述【{encoding.EncodingName}】")
Console.WriteLine($"WindowsCodePage:【{encoding.WindowsCodePage}】,WebName:【{encoding.WebName}】,HeaderName:【{encoding.HeaderName}】,BodyName:【{encoding.BodyName}】")
Console.ReadLine()
End Sub

Private Function GetTextFileEncodingType(fileName As String) As Encoding
Dim encoding As Encoding = Encoding.Default
Dim fileStream As New FileStream(fileName, FileMode.Open, FileAccess.Read)
Dim binaryReader As New BinaryReader(fileStream, encoding)
Dim buffer As Byte() = binaryReader.ReadBytes(CInt(fileStream.Length))
binaryReader.Close()
fileStream.Close()
If buffer.Length >= 3 AndAlso buffer(0) = 239 AndAlso buffer(1) = 187 AndAlso buffer(2) = 191 Then
encoding = Encoding.UTF8
ElseIf buffer.Length >= 3 AndAlso buffer(0) = 254 AndAlso buffer(1) = 255 AndAlso buffer(2) = 0 Then
encoding = Encoding.BigEndianUnicode
ElseIf buffer.Length >= 3 AndAlso buffer(0) = 255 AndAlso buffer(1) = 254 AndAlso buffer(2) = 65 Then
encoding = Encoding.Unicode
ElseIf IsUTF8Bytes(buffer) Then
encoding = Encoding.UTF8
End If
Return encoding
End Function

Private Function IsUTF8Bytes(data As Byte()) As Boolean
Dim charByteCounter As Integer = 1 '计算当前正分析的字符应还有的字节数
Dim curByte As Byte '当前分析的字节.
For i As Integer = 0 To data.Length - 1
curByte = data(i)
If charByteCounter = 1 Then
If curByte >= &H80 Then
'判断当前
While ((curByte <<= 1) And &H80) <> 0
charByteCounter += 1
End While
'标记位首位若为非0 则至少以2个1开始 如:110XXXXX...........1111110X
If charByteCounter = 1 OrElse charByteCounter > 6 Then
Return False
End If
End If
Else
'若是UTF-8 此时第一位必须为1
If (curByte And &HC0) <> &H80 Then
Return False
End If
charByteCounter -= 1
End If
Next
If charByteCounter > 1 Then
Throw New Exception("非预期的byte格式")
End If
Return True
End Function