Question

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Whats the main difference between int.Parse() and Convert.ToInt32

I would like to know what are PRO and CONS of using Convert.ToInt32 VS int.Parse.

Here an example of syntax I am using:

            int myPageSize = Convert.ToInt32(uxPageSizeUsersSelector.SelectedValue);

            int myPageSize = int.Parse(uxPageSizeUsersSelector.SelectedValue);

I also found out these articles, maybe they can help for a discussion:

• http://dotnetperls.com/int-parse
• http://aspdotnethacker.blogspot.com/2010/04/difference-between-int32parsestring.html
• http://aspdotnethacker.blogspot.com/p/visual-studio-performance-wizard.html

Answer 1

Convert.ToInt32 is for dealing with any object that implements IConvertible and can be converted to an int. Also, Convert.ToInt32 returns 0 for null, while int.Parse throws a ArgumentNullException.

int.Parse is specifically for dealing with strings.

As it turns out, the string type’s IConvertible implementation merely uses int.Parse in its ToInt32 method.

So effectively, if you call Convert.ToIn32 on a string, you are calling int.Parse, just with slightly more overhead (a couple more method calls).

This is true for any conversion from string to some primitive type (they all call Parse). So if you’re dealing with strongly-typed string objects (e.g., you’re parsing a text file), I’d recommend Parse, simply because it’s more direct.

Converting arbitrary objects (returned to you by some external library, for instance) is the scenario where I’d opt for using the Convert class.