使用BinaryWriter和BinaryReader操作搜索c＃

问题描述

我有一些像roll，name和mark这样的数据。我把这些写到文件中。喜欢

Hi,

I have some data like roll, name and mark. I have written these to a file. Like

FileStream fs = new FileStream("data.dat",FileMode.OpenOrCreate);
           BinaryWriter br = new BinaryWriter(fs);
           br.Write(Convert.ToInt32(textBox1.Text)); //Textbox1 for int roll
           br.Write(textBox2.Text);                  // Textbox2 for string name
           br.Write(Convert.ToInt32(textBox3.Text)); //Textbox3 for int mark
           fs.Flush();
           br.Flush();
           fs.Close();
           br.Close();

我们每次都可以使用BinaryWriter在新行中写一个像roll，name和merk这样的新记录。我们每次使用BinaryReader都可以读取新行。

现在我必须使用BinaryReader类从该文件中搜索基于roll的任何记录。如何在文本框中输入卷并从文件中搜索记录。



谢谢。

Can we write a new record like roll, name and merk in new line every time using BinaryWriter. Can we read new line every time using BinaryReader.
Now I have to search any record based on roll from that file using BinaryReader class . How can i enter a roll in textbox and search the record from file.

Thank you.

推荐答案

using System;
using System.IO;

namespace Stuff {

    class Program {

        private static void Append(int a, string b, int c) {
            using (var fs = new FileStream(@"C:\Temp\data.dat", FileMode.Append)) {
                using (var br = new BinaryWriter(fs)) {
                    br.Write(a);
                    br.Write(b);
                    br.Write(c);
                }
            }
        }

        private static bool TryFindString(string s, out int a, out int c) {
            a = 0;
            c = 0;
            using (var fs = new FileStream(@"C:\Temp\data.dat", FileMode.Open)) {
                using (var br = new BinaryReader(fs)) {
                    while (fs.CanRead) {
                        // It is important to read all the values here in the order
                        // they were written, not just the search item.
                        a = br.ReadInt32();
                        var b = br.ReadString();
                        c = br.ReadInt32();

                        if (s == b)
                            return true;
                    }
                }
            }
            return false;
        }

        static void Main(string[] args) {
            Append(1, "A", 100);
            Append(2, "B", 200);

            int a, c;
            if (TryFindString("B", out a, out c)) {
                Console.WriteLine("Found string {0}, a={1} and b={2}", "B", a, c);
            }
        }
    }
}

希望这有帮助，

Fredrik

Hope this helps,
Fredrik

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