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.
Remarks
Use the 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.
Unicode Characters
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.
You can use methods like IsDigit and IsPunctuation on a Char
variable to determine its Unicode classification.
Type Conversions
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 Char
value.
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
Programming Tips
Negative Numbers.
Char
is an unsigned type and cannot represent a negative value. In any case, you should not useChar
to 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
Byte
instead ofChar
in your new Visual Basic code.Widening. The
Char
data type widens toString
. This means you can convertChar
toString
and will not encounter a System.OverflowException.Type Characters. Appending the literal type character
C
to a single-character string literal forces it to theChar
data type.Char
has no identifier type character.Framework Type. The corresponding type in the .NET Framework is the System.Char structure.
See also
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