How to validate negative string number

Question

i'm currently doing a C# WPf application. May i know how to validate for the string value? Example "0.00" or "-1.00",etc?

Because both of them is return as a string that i retrieve from SAP, is there anyway to check?

Sorry I'm still new to C# , not really familiar with the function that have in the C#.

Validate it based on what rules? What aspect do you want validated? — Jeroen Vannevel, Jun 25 '15 at 09:27
negative string means? do you want to check the content is a number and wether its negative? — Joseph, Jun 25 '15 at 09:29
@JeroenVannevel Actually i was trying to check for current balance left, if the SAP return me positive balance then i proceed, if it return negative value then i stop the process. Example "Current Balance : 10.00" then proceed , else if "Current Balance: -15.00" then exit program — Marcus Tan, Jun 25 '15 at 09:30
Dending where you do it, it looks like floating numbers, so you could try do to Double.TryParse("the string",out doubleVariable) it returns a booleans if it is a double or not — Henrik Bøgelund Lavstsen, Jun 25 '15 at 09:30
@MarcusTan If thats the Case i would look into regualar expression, because the value is mixed with characters — Henrik Bøgelund Lavstsen, Jun 25 '15 at 09:32
Anyway, I'm not checking whether the string is number or not. What i wanted to check is whether the string that return is negative value or not. Please don't simply mark this is duplicate or what... — Marcus Tan, Jun 25 '15 at 09:33
You may check the result from `decimal.TryParse(s, NumberStyles.Any, CultureInfo.InvariantCulture, out temp_decimal)`. InvariantCulture is necessary if your string is always point sign. — i486, Jun 25 '15 at 09:35

David Pilkington · Accepted Answer · 2015-06-25T09:42:15.920

1

I assume you want to check if the number that you get back is a negative number?

double number = 0;
if(double.TryParse(myString,out number)){
   if (number > 0)
       \\Do something
}

edited Jun 25 '15 at 09:42

answered Jun 25 '15 at 09:32

David Pilkington

Yes, you are right. I wanted to check the number whether i get is negative number or not. Unlike those simply mark the question withoutht understand the question asked. Let me try it out firsts. thanks for your answer – Marcus Tan Jun 25 '15 at 09:34
and for your correction it was if(double.TryParse(myString,out number)) – Marcus Tan Jun 25 '15 at 09:41

Bellash · Answer 2 · 2015-06-26T08:01:24.793

0

you can use TryParse() as bellow

    string s="0.00";
    double dvalue=0;
    if(!double.TryParse(s,out dvalue)){
       //not valid
    }

edited Jun 26 '15 at 08:01

answered Jun 25 '15 at 09:30

Bellash

Pedro Isaaco · Answer 3 · 2015-06-25T09:32:50.653

0

Do you always have a double value? Try

Double.Parse(...)

edit: corrected method

edited Jun 25 '15 at 09:32

answered Jun 25 '15 at 09:30

Pedro Isaaco

3 Answers3