CODEWITHSUNDEEP
c#
yappy
yappy

Reputation: 25

How to convert textbox to float only if not empty?

How can I convert a textbox into a float only when the textbox has value?

I currently have this float test = (float)Convert.ToDouble(textbox.Text);

It works fine, But gives an error if the textbox is empty.

Upvotes: 0

Views: 740

Answers (4)

Fruchtzwerg
Fruchtzwerg

Reputation: 11389

A very common way is to use double.TryParse to do the conversion. This way you can handle empty and invalid values with a single statement.

bool success = double.TryParse(textbox.Text, out value);

Don't forget to check success and handle a possible failure.

Upvotes: 0

daniell89
daniell89

Reputation: 2272

I think that better solution will be:

float test = float.NaN;
if(float.TryParse(textbox.Text, out test ))
{
     // your code here
}

Upvotes: 1

fdsafdsafdsafdsafs
fdsafdsafdsafdsafs

Reputation: 169

It really is as simple as including this in an If statement. 

float test;

if(textbox.Text.Length > 0) //Or (textbox.Text != "")
    test = (float)Convert.ToDouble(textbox.Text);

As an additional suggestion, multiple layers of validation is always a good thing. If you have something like a submit button, you should test against required fields being empty on the UI BEFORE it gets to the point where it is converted.

Upvotes: 0

MotKohn
MotKohn

Reputation: 3965

There are many ways to do this, but generally you test with an if. For example:

float test;
if (!string.IsNullOrWhiteSpace(textbox.text))
    test = (float)Convert.ToDouble(textbox.Text);

Upvotes: 0

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