这必须是数值 [英] This must be a numeric value

问题描述

我希望如果我写一个字符串就会出错。我怎么能写这个代码只取一个数值。

Hi,
I want that if I write a string that it gives an error. How can I write that this code only take a numeric value.

//This must be a numeric value

           Console.Write("Geef je startsalaris in: ");
           salaris = Convert.ToDouble(Console.ReadLine());
           while(//here should i say that if the user gives a string it will give this error)
           {
               Console.WriteLine("dit is geen numeriek waarde");
               Console.Write("Geef je startsalaris in: ");
               salaris = Convert.ToDouble(Console.ReadLine());
           }

我的尝试：



i尝试了很多东西，但没有任何解决方案。

What I have tried:

i have tried many things but without any solution.

推荐答案

TryParse功能是专为此类操作而设计的。

The TryParse function is specially designed for this type of operation.

Console.Write("Geef je startsalaris in: ");
while(!double.TryParse(Console.ReadLine(), out salaris))
{
    Console.WriteLine("dit is geen numeriek waarde");
    Console.Write("Geef je startsalaris in: ");
}

试试这个 -

Try this -

double x = 0.0;
bool flag = true;

Console.WriteLine("Enter value : ");

while (flag)
{
    try
    {
        x = Convert.ToDouble(Console.ReadLine());
        flag = false;
    }
    catch (Exception ex)
    {
        Console.WriteLine("Enter correct value :");
        flag = true;
    }
}

Console.WriteLine("ok :" + x);

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