关于C#.dat文件读取

[ige5460]

.dat文件是c创建的，格式是4个字节的int和60个字节的char（中文，不足为/0）连续保存,

现在在c#中要如何读取

[ige5460]

执行到
n = fs.Read(charBytes, numBytesReaded, 60);
出错，错误提示：
偏移量和长度超出数组的界限，或者计数大于从索引到源集合结尾处的元素数量。

[zgke]

[Quote=引用 1 楼 gomoku 的回复:]
You might try this one:


C# code
byte[] rawBytes = System.IO.File.ReadAllBytes(@"my.dat");
int i = BitConverter.ToInt32(rawBytes, 0);
string s = Encoding.Default.GetString(rawBytes, 4, 60); //or ASCII encoding, according to your impelmentation
[/Quote]

这个根据你字符保存的时候用什么编码就用什么编码读

[ige5460]

非常感谢两位大哥的热心帮助，我这样处理
String[] words = new String[3];
byte[] rawBytes = System.IO.File.ReadAllBytes(@"D:\chinese.dat");
int numBytesToRead = rawBytes.Length;
int numBytesReaded = 0;
while (numBytesToRead > 0)
{
int i = BitConverter.ToInt32(rawBytes, numBytesReaded);
numBytesReaded += 4;
numBytesToRead -= 4;
string s = Encoding.Default.GetString(rawBytes, numBytesReaded, 60);
numBytesReaded += 60;
numBytesToRead -= 60;
words[0] = i.ToString().PadLeft (3);
words[1] = s;
this.dataGridView1.Rows.Add(words);
}

现在还有个问题，就是对字符串做修改后如何按照原来的格式保存

[GTX280]

            FileStream fs = new FileStream(@"C:\test",FileMode.Open,FileAccess.ReadWrite);
            int value = 265;
            byte[] bytesInt = BitConverter.GetBytes(value);
            fs.Write(bytesInt, 0, 4);
            char[] valueStr = ("这次是测试").ToCharArray();
            byte[] bytes = new byte[60];
            byte[] strBytes = Encoding.Unicode.GetBytes(valueStr, 0, valueStr.Length);
            for (int i = 0; i < 60; i++)
            {
                if (i < strBytes.Length)
                {
                    bytes[i] = strBytes[i];
                }else
                {
                    bytes[i] = 0;//'\0'
                }
            }
            fs.Write(bytes, 0, 60);

　　　　　　//保存文件
　　　　　　fs.Flush();
            fs.Close();

[gomoku]

You might try this one:

    byte[] rawBytes = System.IO.File.ReadAllBytes(@"my.dat");
    int i = BitConverter.ToInt32(rawBytes, 0);
    string s = Encoding.Default.GetString(rawBytes, 4,  60); //or ASCII encoding, according to your impelmentation

[GTX280]

用FileStream

            FileStream fs = new FileStream(@"C:\test.dat", FileMode.Open, FileAccess.Read);
            int numBytesToRead = (int)fs.Length;
            int numBytesReaded = 0;
            while (numBytesToRead > 0)
            {
                byte[] intBytes = new byte[4];
                int n = fs.Read(intBytes, numBytesReaded, 4);
                numBytesReaded += n;
                numBytesToRead -= n;
                if (n == 0)
                {
                    break;
                }
                int value = BitConverter.ToInt32(intBytes, 0);//get the int value
                byte[] charBytes = new byte[60];
                n = fs.Read(intBytes, numBytesReaded, 60);
                if (n == 0)
                {
                    break;
                }
                string valueStr = BitConverter.ToString(charBytes, 0);//get the string value
                numBytesReaded += n;
                numBytesToRead -= n;
            }

[yinjianbbq20]

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