Char.IsLetter Method (Char)
Microsoft Silverlight will reach end of support after October 2021. Learn more.
Indicates whether the specified Unicode character is categorized as a Unicode letter.
Namespace: System
Assembly: mscorlib (in mscorlib.dll)
Syntax
'Declaration
Public Shared Function IsLetter ( _
c As Char _
) As Boolean
public static bool IsLetter(
char c
)
Parameters
- c
Type: System.Char
The Unicode character to evaluate.
Return Value
Type: System.Boolean
true if c is a letter; otherwise, false.
Remarks
This method determines whether a Char is a member of any category of Unicode letter. Unicode letters include the following:
Uppercase letters, such as U+0041 (LATIN CAPITAL LETTER A) through U+005A (LATIN CAPITAL LETTER Z), or U+0400 (CYRILLIC CAPITAL LETTER IE WITH GRAVE) through U+042F (CYRILLIC CAPITAL LETTER YA). These characters are members of the UnicodeCategory.UppercaseLetter category.
Lowercase letters, such as U+0061 (LATIN SMALL LETTER A) through U+007A (LATIN SMALL LETTER Z), or U+03AC (GREEK SMALL LETTER ALPHA WITH TONOS) through U+03CE (GREEK SMALL LETTER OMEGA WITH TONOS). These characters are members of the UnicodeCategory.LowercaseLetter category.
Title case letters, such as U+01C5 (LATIN CAPITAL LETTER D WITH SMALL LETTER Z WITH CARON) or U+1FFC (GREEK CAPITAL LETTER OMEGA WITH PROSGEGRAMMENI). These characters are members of the UnicodeCategory.TitlecaseLetter category.
Modifiers, such as U+02B0 (MODIFIER LETTER SMALL H) through U+02C1 (MODIFIER LETTER REVERSED GLOTTAL STOP), or U+1D2C (MODIFIER LETTER CAPITAL A) through U+1D61 (MODIFIER LETTER SMALL CHI). These characters are members of the UnicodeCategory.ModifierLetter category.
Other letters, such as U+05D0 (HEBREW LETTER ALEF) through U+05EA (HEBREW LETTER TAV), U+0621 (ARABIC LETTER HAMZA) through U+063A (ARABIC LETTER GHAIN), or U+4E00 (<CJK Ideograph, First>) through U+9FC3 (<CJK Ideograph, Last>). These characters are members of the UnicodeCategory.OtherLetter category.
Examples
The following example demonstrates IsLetter.
Module Example
Public Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)
Dim ch8 As Char
ch8 = "8"c
outputBlock.Text &= Char.IsLetter(ch8) & vbCrLf ' Output: "False"
outputBlock.Text += String.Format(Char.IsLetter("sample string", 5)) & vbCrLf ' Output: "True"
End Sub
End Module
using System;
public class Example
{
public static void Demo(System.Windows.Controls.TextBlock outputBlock)
{
char ch = '8';
outputBlock.Text += Char.IsLetter(ch).ToString() + "\n";
outputBlock.Text += Char.IsLetter("sample string", 7).ToString() + "\n";
}
// The example displays the following output:
// False
// True
}
Version Information
Silverlight
Supported in: 5, 4, 3
Silverlight for Windows Phone
Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0
XNA Framework
Supported in: Xbox 360, Windows Phone OS 7.0
Platforms
For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.