Personally I expected the compiler to complain about it, but then I don't have the resolution steps memorised. AdamHouldsworth: It's not strange at all - that's how overload resolution works, as there's a conversion from null to string and null to object so both are candidate methods , and string to object , but not object to string so the conversion to string is a "better" conversion.
It's overloading, not overriding, by the way. JonSkeet Yeah, I know it was overloading, I just typed the wrong word. So it picks the most derived overload when null is provided? Saying that, just tried it with my own method and it chose the non- object route, I didn't realise it handled object like that - I was expecting the ambiguous call error which I get when specifying yet another overload of a reference type.
Sounds like a good answer, but clicking on the link doesn't lead to the text you seem to have quoted. Was this text removed, or did you make it up? Show 1 more comment. Well, the method could have been documented to return 1, or int. MinValue etc What does the default value of Int32 being zero have anything to do with the fact Int32 cannot be null unless you make it nullable and the method in question when presented by a null value turns 0. As Jon points out if the reason you point out was really the reason they would have returned perhaps int.
MinValue and made sure to covert it to a non-signed integer. Tim S. Parse null , on the other hand, throws ArgumentNullException. It is appropriate. Shyju Shyju k gold badges silver badges bronze badges. For you to have an InvalidCastException you have to make a non-controlled cast. The use of Convert. ToInt32 var Is useful when you distrust the value in var , as when reading from a database. Daniel Ferreira Daniel Ferreira 86 2 2 bronze badges. Did it work at some point? Sign up or log in Sign up using Google.
Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown. The Overflow Blog. Stack Gives Back Safety in numbers: crowdsourcing data on nefarious IP addresses. Featured on Meta. New post summary designs on greatest hits now, everywhere else eventually. Linked Related You can use a couple built in methods, as shown below, to convert a string to int. Both of these would throw an exception if the string value is not a valid integer.
The built-in methods Convert. ToInt32 and int. Parse produce the same results, except for the null string scenario. If we peek under the covers to see what the source code for Convert. ToInt32 does, you can see it has special logic to look for null and calls int. Parse internally. Bad data is inevitable. You should definitely handle potential exceptions when parsing data and converting datatypes. In this example, possible exceptions converting a string to int.
Luckily, the. NET Framework provides int. TryParse which is designed for this exact problem. Below is an example of how to properly use it.
The only problem is that the variable parsedResult will end up being a 0 if the TryParse fails. Forgot your password? Ask a Question. How to safe cast dbnull value to int in C. Please Sign up or sign in to vote. See more: C. Hello I am retrive the Int value from datagridview to int variable. Some time datagridview row value will be null. Copy Code. Add a Solution. Top Rated Most Recent. Accept Solution Reject Solution. You can't cast a DBNull value to any type: that's what DBNull is saying - it's a special value which says "the database contains no value in this column".
Trying to cast it to an integer is like trying to make this sum work:. Posted May am OriginalGriff. Thanks sir satisfy with answer.
Posted May am omerkamran.
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