How would I parse an empty string? int.Parse(Textbox1.text) gives me an error:
Input string was not in a correct format.
System.FormatException: Input string was not in a correct format.
If the text is empty (Textbox1.text = ''), it throws this error. I understand this error but not sure how to correct this.
If you're looking to default to 0 on an empty textbox (and throw an exception on poorly formatted input):
int i = string.IsNullOrEmpty(Textbox1.Text) ? 0 : int.Parse(Textbox1.Text);
If you're looking to default to 0 with any poorly formatted input:
int i;
if (!int.TryParse(Textbox1.Text, out i)) i = 0;
int i; if (!int.TryParse(Textbox1.Text, out i)) i = 0; or someone thinks the following would work int i = -1; int.TryParse(Textbox1.Text, out i);
out i - it will be assigned to 0 if not parsed, so for zero check and assignment are extra.
IsNullOrWhitespace for this.Well, what do you want the result to be? If you just want to validate input, use int.TryParse instead:
int result;
if (int.TryParse(Textbox1.Text, out result)) {
// Valid input, do something with it.
} else {
// Not a number, do something else with it.
}
if(!String.IsNullOrEmpty(Textbox1.text))
var number = int.Parse(Textbox1.text);
Or even better:
int number;
int.TryParse(Textbox1.Text, out number);
Try this:
int number;
if (int.TryParse(TextBox1.Text, out number))
{
//Some action if input string is correct
}
If the input is a number or an empty string this will work. It will return zero if the string is empty or else it will return the actual number.
int.Parse("0"+Textbox1.Text)
You could also use an extension method like this:
public static int? ToNullableInt32(this string s)
{
int i;
if (Int32.TryParse(s, out i)) return i;
return null;
}
Here's the reference: How to parse a string into a nullable int in C# (.NET 3.5)
I had the same problem with int.TryParse() erroring with negative numbers.
Here's what I used and it worked:
int.TryParse("-1",NumberStyles.Number, CultureInfo.InvariantCulture, out var num);
The NumberStyles enum can be OR'd together with '|', so you can pick and choose the format combinations. NumberStyles.Number covers about any number.
you can wrap it with simple try/catch...
catch(System.FormatException)
