正在从二进制文件中读取注册表
本文关键字:读取 注册表 二进制文件 | 更新日期: 2023-09-27 18:22:49
在二进制文件中写入后的程序注册表包含:
StringBuilder name0 = new StringBuilder(15);
int stock0, safe0;
double cost0;
必须通过根据注册表的位置提供id来读取一个注册表的数据。
因此,因为注册表是20个字节,所以每个注册表的位置都是:
pos = (id-1) * 20;
对吧?
问题是StringBuilder
不能容纳15个字符,而是每次写入的名称的长度,而不是读取所需的数据,而是读取垃圾。难道没有一种方法可以声明一个始终具有精确大小的字符串,以便正确读取数据吗?
代码:
public static void Main(string[] args)
{
Console.WriteLine("Give file name: ");
string f = Console.ReadLine();
StringBuilder name0 = new StringBuilder(15);
bool criterion = true;
int stock0, safe0;
double cost0;
long id, pos;
try
{
FileStream fs = File.Open(f, FileMode.Create, FileAccess.ReadWrite);
BinaryWriter writer = new BinaryWriter(fs);
BinaryReader reader = new BinaryReader(fs);
while (criterion != false)
{
Console.WriteLine("Give name (10 char) or STOP for end");
name0.Insert(0, Console.ReadLine());
if ((name0.ToString()).Equals("STOP"))
criterion = false;
else
{
Console.WriteLine("Stock : ");
stock0 = Int32.Parse(Console.ReadLine());
Console.WriteLine("Safe: ");
safe0 = Int32.Parse(Console.ReadLine());
Console.WriteLine("Cost: ");
cost0 = double.Parse(Console.ReadLine());
writer.Write(name0.ToString());
writer.Write(stock0);
writer.Write(safe0);
writer.Write(cost0);
} // else
name0.Remove(0, name0.Length);
} //while
Console.WriteLine(" Give ID: ");
id = long.Parse(Console.ReadLine());
pos = (id - 1) * 20; //20 = megethos eggrafis(2 int+ 1db + 16chars)
if ((pos < fs.Length) && (id != 0))
{
fs.Seek(pos, SeekOrigin.Begin);
name0.Insert(0, reader.ReadChars(name0.Length));
Console.WriteLine("Name: {0}", name0);
stock0 = reader.ReadInt32();
Console.WriteLine("'nStock: {0}", stock0);
safe0 = reader.ReadInt32();
Console.WriteLine("'nSafe: {0}", safe0);
cost0 = reader.ReadDouble();
Console.WriteLine("'nCost: {0}", cost0);
name0.Length = 0;
}
fs.Close();
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
}
不能在C#中声明固定长度的字符串,除非将其声明为char[15]
。但你可以在书写时手动用空格填充数值,在阅读时修剪空格:
// writing
writer.Write(name0.ToString().PadRight(15));
//reading
name0.Insert(0, reader.ReadChars(15));
name0 = new StringBuilder(name0.ToString().Trim());