Question

我编写的代码不应该接受错误的日期格式。 Mine显示无效选项，但在日志文件中存储了错误的日期格式。如果日期格式不正确，则不应将其存储在文本文件中。

using System;
using System.Collections;
using System.IO;
using System.Globalization;
class FunWithScheduling
{
    public void AddView()
    {
        FileStream s = new FileStream("Scheduler.txt",FileMode.Append,FileAccess.Write);
        StreamWriter w = new StreamWriter(s);
        Console.WriteLine("Enter the Name of the Person To Be Met:");
        string Name = Console.ReadLine();
        Console.WriteLine("Enter the Date Scheduled For the Meeting:");
        string Date = Console.ReadLine();
        DateTime date;

        if(!DateTime.TryParseExact(Date,"MM-dd-yyyy",new CultureInfo("en-US"),DateTimeStyles.None,out date))
        {
            Console.WriteLine("Invalid Choice");
        }
        Console.WriteLine("Enter the Time Scheduled For the Meeting:");
        string Time = Console.ReadLine();
        string line = Name + "                                "+ Date +"             " + Time;
        w.WriteLine(line);
        w.Flush();
        w.Close();
        s.Close();
    }

    static void Main()
    {
        FunWithScheduling a = new FunWithScheduling();
        a.AddView();
    }
}

此修改后的程序不起作用。虽然永远不会结束，但不接受日期的正确格式，也不保存在文本文件中。

我不允许使用字符串构建器。

using System;
using System.Collections;
using System.IO;
using System.Globalization;
class FunWithScheduling
{
    public void AddView()
    {
        FileStream s = new FileStream("Scheduler.txt",FileMode.Append,FileAccess.Write);
        StreamWriter w = new StreamWriter(s);
        Console.WriteLine("Enter the Name of the Person To Be Met:");
        string Name = Console.ReadLine();
        Console.WriteLine("Enter the Date Scheduled For the Meeting:");
        string Date = Console.ReadLine();
        DateTime date;
        if(!DateTime.TryParseExact(Date,"MM-dd-yyyy",new CultureInfo("en-US"),DateTimeStyles.None,out date))
        {
            Console.WriteLine("Invalid date format!");
            while(!DateTime.TryParseExact(Date,"MM-dd-yyyy",new CultureInfo("en-US"),DateTimeStyles.None,out date))
            {
                Console.WriteLine("Invalid Date Entered, please format MM-dd-yyyy");
                Date = Console.ReadLine();
            }
        }
        Console.WriteLine("Enter the Time Scheduled For the Meeting:");
        string Time = Console.ReadLine();
        string line = Name + "                                "+ Date +"             " + Time;
        w.WriteLine(line);
        w.Flush();
        w.Close();
        s.Close();
    }

    static void Main()
    {
        FunWithScheduling a = new FunWithScheduling();
        a.AddView();
    }
}

Answer 1

你必须添加：

return;

之后：

Console.WriteLine("Invalid Choice");

最好将FileStream和StreamWriter初始化移至条件检查之后：

using System;
using System.Collections;
using System.IO;
using System.Globalization;
class FunWithScheduling
{
     public void AddView()
     {
        Console.WriteLine("Enter the Name of the Person To Be Met:");
        string Name = Console.ReadLine();
        Console.WriteLine("Enter the Date Scheduled For the Meeting:");
        string Date = Console.ReadLine();
        DateTime date;
        if(!DateTime.TryParseExact(Date,"MM-dd-yyyy",new CultureInfo("en-US"),DateTimeStyles.None,out date))
        {
               Console.WriteLine("Invalid Choice");
               return;
        }
        Console.WriteLine("Enter the Time Scheduled For the Meeting:");
        string Time = Console.ReadLine();
        string line = Name + "                                "+ Date +"             " + Time;
        FileStream s = new FileStream("Scheduler.txt",FileMode.Append,FileAccess.Write);
        StreamWriter w = new StreamWriter(s);
        w.WriteLine(line);
        w.Flush();
        w.Close();
        s.Close();
      }
      static void Main()
      {
        FunWithScheduling a = new FunWithScheduling();
        a.AddView();
      }
}

Answer 2

我建议您使用“else”语句来解决“Date”问题。然后使用String Builder代替+并构建字符串。

我试图在这里帮助你，但我没有通过编译器运行它。

using System;
using System.Collections;
using System.IO;
using System.Globalization;
using System.Text;
class FunWithScheduling
{
     public void AddView()
     {
        FileStream s = new FileStream("Scheduler.txt",FileMode.Append,FileAccess.Write);
        StreamWriter w = new StreamWriter(s);
        var builder = new StringBuilder();
        Console.WriteLine("Enter the Name of the Person To Be Met:");
        string Name = Console.ReadLine();
        builder.Append(Name);
        Console.WriteLine("Enter the Date Scheduled For the Meeting:");
        string Date = Console.ReadLine();
        DateTime date;
        if(!DateTime.TryParseExact(Date,"MM-dd-yyyy",new CultureInfo("en-US"),DateTimeStyles.None,out date))
        {
               Console.WriteLine("Invalid Choice");
        } else {
            builder.Append(date.ToString("MMMM dd, yyyy"));
        }
        Console.WriteLine("Enter the Time Scheduled For the Meeting:");
        string Time = Console.ReadLine();
        builder.Append(Time);
        w.WriteLine(builder.ToString());
        w.Flush();
        w.Close();
        s.Close();
      }
      static void Main()
      {
        FunWithScheduling a = new FunWithScheduling();
        a.AddView();
      }
}

您也可以尝试使用与此类似的while语句，以强制用户输入正确的日期。

    while(!DateTime.TryParseExact(Date,"MM-dd-yyyy",new CultureInfo("en-US"),DateTimeStyles.None,out date)){
        Console.WriteLine("Invalid Date Entered, please format MM-dd-yyyy");
        Date = Console.ReadLine();
    }

Answer 3

//输入日期无效时，将日期设为空白;它不会存储在文本文件中。

if(!DateTime.TryParseExact(Date,"MM-dd-yyyy",
   new CultureInfo("en-US"),DateTimeStyles.None,out date))
{
    Console.WriteLine("Invalid Choice");
    Date = "";
}

Answer 4

首先，是的，使用StringBuilder而不是+ with string，因为当你这样做时，string将乘以两个字符串的内存使用量，这意味着你有2个内存分配用于2个独立的字符串，并且1对于受影响的，只是未来的提示。

你需要做的就是做

StringBuilder sb = new StringBuilder();

sb.Append(Name);

if(!DateTime.TryParseExact(Date,"MM-dd-yyyy",new CultureInfo("en-US"),DateTimeStyles.None,out date))
    {
           Console.WriteLine("Invalid Choice");

    }
    else 
    {
        sb.Append(Date);
    }

然后当您写入文件本身时，只需执行

w.WriteLine(sb.ToString());

Answer 5

当用户输入错误的日期时，您有2个选项：

关闭流并退出代码。
要求用户通过指定格式重新输入日期。

要关闭流并退出，您必须在以下代码后添加以下代码：

Console.WriteLine("Invalid Choice");
w.Flush();
w.Close();
s.Close();
return;

和

要让用户重新输入，直到他指定正确答案，请在以下代码后添加以下代码：

Console.WriteLine("Invalid Choice");

while(!DateTime.TryParseExact(Date, "MM-dd-yyyy", new CultureInfo("en-US"), DateTimeStyles.None, out date))
{    
    Console.WriteLine("Invalid Date Entered, please format MM-dd-yyyy");
    Date = Console.ReadLine();
}

在我的c＃程序中没有获得预期的输出，日期的错误格式被写入文件中

5 个答案: