Question

我试图在21天内使用Sams Teach Yourself C＃来学习C＃的基础知识。

我通过从第1天类型和运行部分逐行复制来创建此程序。它编译得很好，但是当你运行它时会出现这个错误：“输入字符串的格式不正确”。

我正在从控制台运行程序。

我正在使用Visual Studio 2010 Express编辑器。

我复制的代码是：

using System;
using System.IO;

/// <summary>
/// Class to number a listing. Assumes fewer than 1000 lines.
/// </summary>

class NumberIT
{
    /// <summary>
    /// The main entry point for the application.
    /// </summary>

    public static void Main(string[] args)
    {
        // check to see if a file name was included on the command line.

        if (args.Length <= 0)
        {
            Console.WriteLine("\nYou need to include a filename.");
        }
        else
        {
            // declare objects for connecting to files...
            StreamReader InFile = null;
            StreamWriter OutFile = null;

            try
            {
                // Open file name included on command line...
                InFile = File.OpenText(args[0]);

                // Create the output file...
                OutFile = File.CreateText("outfile.txt");
                Console.Write("\nNumbering...");

                // Read first line of the file...
                string line = InFile.ReadLine();
                int ctr = 1;

                // loop through the file as long as not at the end...
                while (line != null)
                {
                    OutFile.WriteLine("{1}: {2}", ctr.ToString().PadLeft(3, '1'), line);
                    Console.Write("..{1]..", ctr.ToString());
                    ctr++;
                    line = InFile.ReadLine();
                }
            }

            catch (System.IO.FileNotFoundException)
            {
                Console.WriteLine("Could not find the file {0}", args[0]);
            }
            catch (Exception e)
            {
                Console.WriteLine("Error: {0}", e.Message);
            }
            finally
            {
                if (InFile != null)
                {
                    // Close the files
                    InFile.Close();
                    OutFile.Close();
                    Console.WriteLine("...Done.");
                }
            }
        }
    }
}

Answer 1

你的罪魁祸首是OutFile.WriteLine和Console.Write语句：

OutFile.WriteLine("{1}: {2}", ctr.ToString().PadLeft(3, '1'), line);
Console.Write("..{1]..", ctr.ToString());

应该是：

OutFile.WriteLine("{0}: {1}", ctr.ToString().PadLeft(3, '1'), line);
Console.Write("..{0}..", ctr.ToString());

请注意，格式字符串中的占位符从0开始。第二个语句的右括号是方括号而不是卷曲括号。

另一个提示：在后一种情况下，您无需在.ToString()上调用ctr，除非您想明确指定文化。

Answer 2

很少有事情需要注意：

OutFile.WriteLine("{1}: {2}", ctr.ToString().PadLeft(3, '1'), line);

索引基于0，因此它应为OutFile.WriteLine("{0}: {1}"...

Console.Write("..{1]..", ctr.ToString());

这里有拼写错误！（我希望！），再次它应该是0而不是1。

输入字符串格式错误

2 个答案: