string str = "fkdfdsfdflkdkfk@dfsdfjk72388389@kdkfkdfkkl@jkdjkfjd@jjjk@";
str = str.Replace("@", Environment.NewLine);
richTextBox1.Text = str;

正如其他人所说，new line char将在windows中的文本文件中为您提供新行。 试试下面的方法:

using System;
using System.IO;

static class Program
{
    static void Main()
    {
        WriteToFile
        (
        @"C:\test.txt",
        "fkdfdsfdflkdkfk@dfsdfjk72388389@kdkfkdfkkl@jkdjkfjd@jjjk@",
        "@"
        );

        /*
        output in test.txt in windows =
        fkdfdsfdflkdkfk@
        dfsdfjk72388389@
        kdkfkdfkkl@
        jkdjkfjd@
        jjjk@ 
        */
    }

    public static void WriteToFile(string filename, string text, string newLineDelim)
    {
        bool equal = Environment.NewLine == "\r\n";

        //Environment.NewLine == \r\n = True
        Console.WriteLine("Environment.NewLine == \\r\\n = {0}", equal);

        //replace newLineDelim with newLineDelim + a new line
        //trim to get rid of any new lines chars at the end of the file
        string filetext = text.Replace(newLineDelim, newLineDelim + Environment.NewLine).Trim();

        using (StreamWriter sw = new StreamWriter(File.OpenWrite(filename)))
        {
            sw.Write(filetext);
        }
    }
}

然后将之前的答案修改为:

Console.Write(strToProcess.Replace("@", "@" + Environment.NewLine));

如果您不希望文本文件中出现换行符，那么就不要保存它。

前面的答案很接近，但为了满足@符号保持接近的实际要求，您希望它是str.Replace("@"， "@" + System.Environment.NewLine)。这将保留@符号，并为当前平台添加适当的换行符。

一个简单的字符串替换就可以完成这项工作。看看下面的示例程序:

using System;

namespace NewLineThingy
{
    class Program
    {
        static void Main(string[] args)
        {
            string str = "fkdfdsfdflkdkfk@dfsdfjk72388389@kdkfkdfkkl@jkdjkfjd@jjjk@";
            str = str.Replace("@", "@" + Environment.NewLine);
            Console.WriteLine(str);
            Console.ReadKey();
        }
    }
}

根据你对其他人的回复，这就是你想要的。

string file = @"C:\file.txt";
string strToProcess = "fkdfdsfdflkdkfk@dfsdfjk72388389@kdkfkdfkkl@jkdjkfjd@jjjk@";
string[] lines = strToProcess.Split(new char[] { '@' }, StringSplitOptions.RemoveEmptyEntries);

using (StreamWriter writer = new StreamWriter(file))
{
    foreach (string line in lines)
    {
        writer.WriteLine(line + "@");
    }
}