Difference between (int), Int32.Parse and Convert.ToInt32?

Question

Hi,

  I have been wondering. In which scenario, I should be using (int), Int32.Parse and Convert.ToInt32?

  Or are they the same? I do notice in certain condition that i cannot cast directly using (int) and I have to use Convert.ToInt32.

  I am not that sure why i do that. I just need some confirmations from you all.

Thank you.

Cheers.

Answer 1

Good question.

Oddly enough, it appears that Convert.ToInt32() has a completely different stack trace than Int32.Parse().

I wonder why the implementation is different?

Answer 2

Basically the Convert class makes it easier to convert between all the base types.

The Convert.ToInt32(String, IFormatProvider) underneath calls the Int32.Parse. So the only difference is that if a null string is passed to Convert it returns 0, whereas Int32.Parse throws an ArgumentNullException.

It is really a matter of choice whichever you use.

Also have a look at the new .NET 2.0 method Int32.TryParse, which attempts to convert a string to an int without throwing an exception.

Answer 3

Thanks for the replies.

Now i understand. One more question.

Is (int) same with Int32.Parse? So underneath of (int) is Int32.Parse?

Thanks.

Answer 4

Doh!

It does help to be looking at the right method in Reflector.

Answer 5

Chua Wen Ching wrote:

Thanks for the replies. Now i understand. One more question. Is (int) same with Int32.Parse? So underneath of (int) is Int32.Parse? Thanks.

No. (int) will only convert types that can be represented as an integer (ie double, long, float, etc) although some data loss may occur.

Int32.Parse will only convert strings to integers.  You can't cast (ie (int)mystring) strings to integers.

Answer 6

David,

  Thanks a lot. I understand now.

Cheers.

Answer 7

Hi.

 

Does anyone know what is the difference between int and integer in BizTalk 2006 ?

 

I mean when i define some namespace  xmlns:int  versus  xmlns:integer  ???

 

 

thnx.

Answer 8

I just want to thanks David M.Kean for his nice clarifications about this point

 

Thanks agian

 

Mohamed

Answer 9

I was experimenting with these 3 conversion methods and I ran into an issue using (int) with objects coming out of an ArrayList.  I have to use Convert.ToInt32, because the object being returned is of type "object { decimal }" (see code below).  Is this showing the "boxed" value?

Code Block

            decimal myDecimalValue = 12312414.12M;

            //int implicitCast = myDecimalValue;            /* Compile Time Error */
            int explicitCast = (int)myDecimalValue;
            //int parseCast = Int32.Parse(myDecimalValue);  /* Compile Time Error */
            int convertCast = Convert.ToInt32(myDecimalValue);

            ArrayList myDecimalCollection = new ArrayList();
            myDecimalCollection.Add(myDecimalValue);

            //int int1 = (int)myDecimalCollection[0];      /* Run-Time Exception, cannot convert "Object{decimal} to int" */
            int int2 = Convert.ToInt32(myDecimalCollection[0]);

Answer 10

check out this post: Why Convert.ToInt32 Might be Dangerous .

Answer 11

I think int32.parse will throw an exception if the argument is null

 

 

GOD BLESS U

Answer 12

Hello,

Refer the link below good explanation of difference between the three.

http://aspdotnethacker.blogspot.com/2010/04/difference-between-int32parsestring.html

Also refer to this link to checkout which is fastest out of three

http://aspdotnethacker.blogspot.com/p/visual-studio-performance-wizard.html

Answer 13

Basically the Convert class makes it easier to convert between all the base types.

The Convert.ToInt32(String, IFormatProvider) underneath calls the Int32.Parse. So the only difference is that if a null string is passed to Convert it returns 0, whereas Int32.Parse throws an ArgumentNullException.

It is really a matter of choice whichever you use.

Also have a look at the new .NET 2.0 method Int32.TryParse, which attempts to convert a string to an int without throwing an exception.

thanks a lot for this clearification

Answer 14

A bit late but Thx anyway for this clearification!

 

Ends