For integral types, this means the range of the source type is a proper subset of the range for the target type. For more information, see How to convert a byte array to an int, How to convert a string to a number, and How to convert between hexadecimal strings and numeric types.įor built-in numeric types, an implicit conversion can be made when the value to be stored can fit into the variable without being truncated or rounded off. ![]() For more information, see User-defined conversion operators.Ĭonversions with helper classes: To convert between non-compatible types, such as integers and System.DateTime objects, or hexadecimal strings and byte arrays, you can use the System.BitConverter class, the System.Convert class, and the Parse methods of the built-in numeric types, such as Int32.Parse. User-defined conversions: User-defined conversions are performed by special methods that you can define to enable explicit and implicit conversions between custom types that do not have a base class–derived class relationship. Typical examples include numeric conversion to a type that has less precision or a smaller range, and conversion of a base-class instance to a derived class. Casting is required when information might be lost in the conversion, or when the conversion might not succeed for other reasons. Examples include conversions from smaller to larger integral types, and conversions from derived classes to base classes.Įxplicit conversions (casts): Explicit conversions require a cast expression. Implicit conversions: No special syntax is required because the conversion always succeeds and no data will be lost. In C#, you can perform the following kinds of conversions: These kinds of operations are called type conversions. Or you might need to assign a class variable to a variable of an interface type. For example, you might have an integer variable that you need to pass to a method whose parameter is typed as double. However, you might sometimes need to copy a value into a variable or method parameter of another type. error CS0029: Cannot implicitly convert type 'string' to 'int' Therefore, after you declare i as an int, you cannot assign the string "Hello" to it, as the following code shows: int i For example, the string cannot be implicitly converted to int. If the string to convert isn't static, it may be better to use a different method, since an if statement checking whether it can be parsed or a try makes it take longer to code and execute than one of the other solutions.Because C# is statically-typed at compile time, after a variable is declared, it cannot be declared again or assigned a value of another type unless that type is implicitly convertible to the variable's type. This is my personal favorite way to convert a string or char to an int, since it's pretty easy to make sense of once you understand the conversions that are performed both explicitly and implicitly. ke圜ode actually implicitly converts ke圜ode to a char first so that it can retrieve a specific index, which is why you need to invoke ToString() on it before you can parse it. ![]() Parse only works if the input is a string that contains only numbers, so it's not always the best to use unless TryParse (the method that checks whether you can parse a string or not) has been invoked and returns true, but in this case, since your input string is always a number, you can use Parse without using TryParse first. This command can be explained like this: int is shorthand for Int32, which contains a Parse(string) method. Instead, you want a more complex conversion, which is the following: int n = Int32.Parse( ke圜ode.SubString( 1, 1 ) ) Īs Ofir said, another method is int number = int.Parse(ke圜ode.ToString()). But if from '2' you want to get 2, that's not the conversion you want. These mappings stipulate that the character '2' corresponds to the number 50, just as they stipulate that the character 'A' corresponds to the number 65.Ĭonvert.ToInt32( char c ) performs a very rudimentary conversion, it essentially reinterprets the character as a number, so it allows you to see what number the character corresponds to. Unicode is such a mapping, ASCII is another mapping that you may have heard of. So, there is a mapping that tells us what number to use to represent each character. But of course, inside the computer, everything is represented as a number. It is not correct to expect that Convert.ToInt32( '2' ) will give you 2, because then what would you expect if you did Convert.ToInt32( 'A' ) ?Ī character is not a number. ![]() That's correct.Īpparently, you did not expect to get 50, you expected to get 2. You observed that when you do int n = Convert.ToInt32( '2' ) you get 50.
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