This must be a numeric value

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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.

C#

//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());
           }

What I have tried:

i have tried many things but without any solution.

Posted 18-Nov-16 23:36pm

akhandafm17

Updated 19-Nov-16 1:03am

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2 solutions

Solution 1

Try this -

C#

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);

Posted 18-Nov-16 23:54pm

pparya27

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Midi_Mick · Accepted Answer · 2016-11-19T01:03:00

Solution 2

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

C#

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: ");
}

Posted 19-Nov-16 1:03am

Midi_Mick