仅限用户输入数字

Question

全新的C#[4小时新:)],但希望有一些关于Board Feet Calculator的指针,将用户输入仅限制为数字,不允许使用字母或特殊字符.

首先,限制是在类,方法和/或程序中进行的吗？(我相信课程和方法)

其次,我在下面看到了一个例子,我会使用类似的东西吗？

第三,如果是这样,我是否需要为KeyPress和KeyPressEventArgs创建单独的类？(我相信他们自动在那里,例如 public char KeyChar { get; set; }

private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
{
    // allows only letters
    if (!char.IsLetter(e.KeyChar))
    {
        e.Handled = true;
    }
}

我的计划

namespace BoardFt_MyTry_
{
    class Program
    {
        static void Main(string[] args)
        {
            Board board = new Board();

        board.lengthOfboard = Convert.ToDouble(askQuestion("What is the length of your board in inches?"));
        board.widthOfboard = Convert.ToDouble(askQuestion("What is the width of your board in inches?"));
        board.thicknessOfboard = Convert.ToDouble(askQuestion("What is the thickness of your board in inches?"));

        Console.WriteLine("Your board has {0} board feet.", board.CalcBoardFt());

        Console.ReadLine();
    }
    private static string askQuestion(string question)
    {
        Console.WriteLine(question);
        return Console.ReadLine();
    }

}

我的董事会成员

namespace BoardFt_MyTry_
{
    class Board
    {
        public double lengthOfboard;
        public double widthOfboard;
        public double thicknessOfboard;

    public double CalcBoardFt()
    {
        double boardft = 0;

        boardft = (this.lengthOfboard * this.widthOfboard * this.thicknessOfboard) / 144;

        return boardft;
    }
}
}

Answer 1

你不能在控制台应用程序中真正做到这一点.您所能做的就是允许用户输入错误数据,然后告诉用户数据不好.

你可以尝试这样的事情:

class Program
{
    public double AskDnoubleQuestion(string message){
        do {
        Console.Write(message);
        var input = Console.ReadLine();

        if (String.IsNullOrEmpty(input)){
            Console.WriteLine("Input is required");
            continue;
         }
         double result;
         if (!double.TryParse(input, out result)){
           Console.WriteLine("Invalid input - must be a valid double");
           continue;
         }
         return result;
    }

    static void Main(string[] args)
    {
        Board board = new Board();

    board.lengthOfboard = AskDoubleQuestion("What is the length of your board in inches?");
    board.widthOfboard = AskDoubleQuestion(askQuestion("What is the width of your board in inches?");
    board.thicknessOfboard = AskDoubleQuestion(askQuestion("What is the thickness of your board in inches?");

    Console.WriteLine("Your board has {0} board feet.", board.CalcBoardFt());

    Console.ReadLine();
}