获取文件编码的一个类

小鱼儿 2022-06-16 14:25 171阅读 0赞

以下是获取文件编码的一个类

using System;  
using System.IO;  
using System.Text;

/// <summary>  
/// FileEncoding 的摘要说明  
/// </summary>  
namespace FileEncoding  
\{  
    /// <summary>  
    /// 获取文件的编码格式  
    /// </summary>  
    public class EncodingType  
    \{  
        /// <summary>  
        /// 给定文件的路径，读取文件的二进制数据，判断文件的编码类型  
        /// </summary>  
        /// <param name="FILE\_NAME">文件路径</param>  
        /// <returns>文件的编码类型</returns>  
        public static System.Text.Encoding GetType(string FILE\_NAME)  
        \{  
            FileStream fs = new FileStream(FILE\_NAME, FileMode.Open, FileAccess.Read);  
            Encoding r = GetType(fs);  
            fs.Close();  
            return r;  
        \}

/// <summary>  
        /// 通过给定的文件流，判断文件的编码类型  
        /// </summary>  
        /// <param name="fs">文件流</param>  
        /// <returns>文件的编码类型</returns>  
        public static System.Text.Encoding GetType(FileStream fs)  
        \{  
            byte\[\] Unicode = new byte\[\] \{ 0xFF, 0xFE, 0x41 \};  
            byte\[\] UnicodeBIG = new byte\[\] \{ 0xFE, 0xFF, 0x00 \};  
            byte\[\] UTF8 = new byte\[\] \{ 0xEF, 0xBB, 0xBF \}; //带BOM  
            Encoding reVal = Encoding.Default;

BinaryReader r = new BinaryReader(fs, System.Text.Encoding.Default);  
            int i;  
            int.TryParse(fs.Length.ToString(), out i);  
            byte\[\] ss = r.ReadBytes(i);  
            if (IsUTF8Bytes(ss) || (ss\[0\] == 0xEF && ss\[1\] == 0xBB && ss\[2\] == 0xBF))  
            \{  
                reVal = Encoding.UTF8;  
            \}  
            else if (ss\[0\] == 0xFE && ss\[1\] == 0xFF && ss\[2\] == 0x00)  
            \{  
                reVal = Encoding.BigEndianUnicode;  
            \}  
            else if (ss\[0\] == 0xFF && ss\[1\] == 0xFE && ss\[2\] == 0x41)  
            \{  
                reVal = Encoding.Unicode;  
            \}  
            r.Close();  
            return reVal;

/// <summary>  
        /// 判断是否是不带 BOM 的 UTF8 格式  
        /// </summary>  
        /// <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;  
        \}

以下是使用示例

\#region 打开按钮  
        /// <summary>  
        /// 打开按钮  
        /// </summary>  
        /// <param name="sender"></param>  
        /// <param name="e"></param>  
        private void txtMenuOpen\_Click(object sender, EventArgs e)  
        \{  
            string fName;  
            OpenFileDialog openFileDialog = new OpenFileDialog();  
            openFileDialog.InitialDirectory = "";//注意这里写路径时要用c:而不是c:　  
            openFileDialog.Filter = "文本文档|\*.txt";  
            openFileDialog.RestoreDirectory = true;  
            openFileDialog.FilterIndex = 1;  
            if (openFileDialog.ShowDialog() == DialogResult.OK)  
            \{  
                fName = openFileDialog.FileName;

txtBox.Text = System.IO.File.ReadAllText(fName,  
                    FileEncoding.EncodingType.GetType(fName));  
            \}

\}  
        \#endregion