Char Data Type (Visual Basic)
Holds unsigned 16-bit (2-byte) code points ranging in value from 0 through 65535. Each code point, or character code, represents a single Unicode character.
Char data type when you need to hold only a single character and do not need the overhead of
String. In some cases you can use
Char(), an array of
Char elements, to hold multiple characters.
The default value of
Char is the character with a code point of 0.
The first 128 code points (0–127) of Unicode correspond to the letters and symbols on a standard U.S. keyboard. These first 128 code points are the same as those the ASCII character set defines. The second 128 code points (128–255) represent special characters, such as Latin-based alphabet letters, accents, currency symbols, and fractions. Unicode uses the remaining code points (256-65535) for a wide variety of symbols, including worldwide textual characters, diacritics, and mathematical and technical symbols.
Visual Basic does not convert directly between
Char and the numeric types. You can use the Asc or AscW function to convert a
Char value to an
Integer that represents its code point. You can use the Chr or ChrW function to convert an
Integer value to a
Char that has that code point.
If the type checking switch (the Option Strict Statement) is on, you must append the literal type character to a single-character string literal to identify it as the
Char data type. The following example illustrates this. The first assignment to the
charVar variable generates compiler error BC30512 because
Option Strict is on. The second compiles successfully because the
c literal type character identifies the literal as a
Option Strict On Module CharType Public Sub Main() Dim charVar As Char ' This statement generates compiler error BC30512 because Option Strict is On. charVar = "Z" ' The following statement succeeds because it specifies a Char literal. charVar = "Z"c End Sub End Module
Charis an unsigned type and cannot represent a negative value. In any case, you should not use
Charto hold numeric values.
Interop Considerations. If you interface with components not written for the .NET Framework, for example Automation or COM objects, remember that character types have a different data width (8 bits) in other environments. If you pass an 8-bit argument to such a component, declare it as
Charin your new Visual Basic code.
Chardata type widens to
String. This means you can convert
Stringand will not encounter a System.OverflowException.
Type Characters. Appending the literal type character
Cto a single-character string literal forces it to the
Charhas no identifier type character.
Framework Type. The corresponding type in the .NET Framework is the System.Char structure.