CODEWITHSUNDEEP
c#
user1968030
user1968030

Reputation:

Casting object that has short value to int in C#

Consider this code: 

private static void Main(string[] args)
{
    short age = 123;
    object ageObject = age;
    //var intAge = (int)ageObject;//Specified cast is not valid.
    int newAge= (short)intAge;
    Console.ReadLine();
}

I have to assign a short value to object and again cast to int, but when I try to this: var intAge = (int)ageObject; I get : Specified cast is not valid. I don't know why?

After search in google i found that should cast to short and assign to int:int newAge= (short)intAge;

Why we should casting to short and assign to int?

Why compiler has this behavior?

Upvotes: 2

Views: 3284

Answers (4)

uguracar
uguracar

Reputation: 21

I didn't understand why you are trying to convert short to object and then int.

You could do short -> int conversion in following ways:

{
short age = 123;
int intAge1 = (short)age;
int intAge2 = (int)age;
int intAge3 = Int16.Parse(age.ToString());
}

Upvotes: 1

Murugavel
Murugavel

Reputation: 279

Use

Convert.ToInt32(ageObject) instead.

It will work

Upvotes: 3

Rohit
Rohit

Reputation: 10236

A boxed value can only be unboxed to a variable of the exact same type This restriction helped in speed optimization that made .NET 1.x feasible before generics came into picture.Take a look at this

simple value types implement the IConvertible interface. Which you invoke by using the Convert class

      short age= 123;
    int ix = Convert.ToInt32(age);

Upvotes: 1

SteveLove
SteveLove

Reputation: 3207

The failure is a runtime error.

The reason for it is the age value has been boxed into an object; unboxing it to the incorrect type (int) is a failure - it's a short.

The cast on the line which you've commented out is an unboxing operation, not just a cast.

Upvotes: 5

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