Using IFormattable to make your output more convenient

Module Module1
Sub Main()
Dim Microsoft_example_about_Account_Number As New Account_Number(34567)
Dim Microsoft_example_about_Tempture As New Temperature(333)
Dim formatProvider() As FormatProvider_class = {
New FormatProvider_class(New Globalization.CultureInfo("de-DE")),
New FormatProvider_class(New Globalization.CultureInfo("fr-FR"))
}
Dim fmt = "{0:H}" & vbNewLine &
"{1:E}" & vbNewLine &
"{2:G}" & vbNewLine &
"{3:G}" & vbNewLine &
"{4:G}" & vbNewLine &
"{5:F}" & vbNewLine
For Each fmtProvider As FormatProvider_class In formatProvider
Console.WriteLine("==========" & fmtProvider.CultureInfo.Name & "============")
Console.WriteLine(String.Format(fmtProvider, fmt,
Microsoft_example_about_Account_Number,
123.45,
#2024/03/12 12:03:24#,
New TimeSpan(12345678),
DayOfWeek.Friday,
Microsoft_example_about_Tempture))
Next
Console.WriteLine($"
{Microsoft_example_about_Account_Number:H}
{123.45:E}
{#2024/03/12 12:03:24#}
{New TimeSpan(12345678)}
{DayOfWeek.Friday:G}
{Microsoft_example_about_Tempture:F}
")
Console.ReadKey()
Console.WriteLine($"{New CultureInfomation_on_Windows():C}") : Console.ReadKey()
BrowseHtml.Show($"{New CultureInfomation_on_Windows():W}")
End Sub
Class BrowseHtml
Class Register_RunTime_data
Sub New(Optional OldFilePath As Boolean = True)
If OldFilePath Then GetHtmlFilePath()
If String.IsNullOrEmpty(HtmlFilePath) Then
HtmlFilePath = IO.Path.ChangeExtension(HtmlFilePath2, "html")
End If
End Sub
Protected Overrides Sub finalize()
SaveHtmlFilePath()
End Sub
Const Myblog = "MyBlog_7", Key = "TempFile"
Public Shared Sub SaveHtmlFilePath()
Interaction.SaveSetting(Reflection.Assembly.GetExecutingAssembly.GetName.Name,
Myblog, Key, HtmlFilePath)
End Sub
Public Shared Sub GetHtmlFilePath()
Try
HtmlFilePath =
Interaction.GetSetting(Reflection.Assembly.GetExecutingAssembly.GetName.Name,
Myblog, Key)
Catch ex As Exception
End Try
End Sub
End Class
Public Shared msedge_exe As String =
IO.Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ProgramFilesX86),
"Microsoft\Edge\Application\msedge.exe")
Public Shared HtmlFilePath1 As String = IO.Path.GetTempFileName
Public Shared HtmlFilePath2 As String = IO.Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop),
IO.Path.GetRandomFileName)
Shared HtmlFilePath As String
Public Shared Sub Show(Html_content As String)
Static For_HtmlFilePath As New Register_RunTime_data()
Using HtmlFile As New IO.StreamWriter(HtmlFilePath, False, Text.Encoding.UTF8),
BrowserProcess As New Process
HtmlFile.Write(Html_content)
HtmlFile.Flush()
BrowserProcess.StartInfo = New ProcessStartInfo(HtmlFilePath) With {
.Verb = "open",
.UseShellExecute = True
}
If Not BrowserProcess.Start() Then Throw New Exception("error in BrowserProcess")
End Using
End Sub
End Class
'#Const trace_it = True
Class FormatProvider_class
Implements IFormatProvider, ICustomFormatter
Public CultureInfo As Globalization.CultureInfo
Sub New(cultureinfo As Globalization.CultureInfo)
If cultureinfo Is Nothing Then
Me.CultureInfo = Globalization.CultureInfo.CurrentCulture
Else
Me.CultureInfo = cultureinfo
End If
Trace_string = New Text.StringBuilder
End Sub
Function GetFormat(FormatType As Type) As Object Implements IFormatProvider.GetFormat
Trace_string.Append(
$"(IFormatProvider.GetFormat) FormatType={FormatType} CultureName={CultureInfo.Name}")
Try
Select Case FormatType
Case GetType(ICustomFormatter)
Return Me
Case GetType(Globalization.NumberFormatInfo)
Trace_string.Append($"Use NumberFormatInfo to parse/format")
Return CultureInfo.NumberFormat
Case GetType(Globalization.DateTimeFormatInfo)
Trace_string.Append($"Use DateTimeFormat to parse/format")
Return CultureInfo.DateTimeFormat
Case Else
Return Nothing
End Select
Catch ex As Exception
Return Nothing
Finally
#If TRACE = trace_it Then
Console.WriteLine(Trace_string) : Trace_string.Clear()
#End If
End Try
End Function
Public Function Format(fmt As String, arg As Object, formatProvider As IFormatProvider) As String _
Implements ICustomFormatter.Format
Trace_string.Append($"(ICustomFormatter.Format__IN){arg.GetType.Name,15} ")
Try
Select Case arg.GetType()
Case GetType(Account_Number)
Case GetType(Temperature)
Case Else
End Select
Return CType(arg, IFormattable).ToString(fmt, Me.CultureInfo)
Finally
Trace_string.Append("(ICustomFormatter.Format__OUT)")
#If TRACE = trace_it Then
Console.WriteLine(Trace_string) : Trace_string.Clear()
#End If
End Try
End Function
Dim Trace_string As Text.StringBuilder
End Class
Structure Account_Number
Implements IFormattable
Public value As Long
Public Sub New(value As Long)
Me.value = value
End Sub
Public Overrides Function ToString() As String
Return Me.ToString("H", Globalization.CultureInfo.CurrentCulture)
End Function
Public Overloads Function ToString(fmt As String) As String
Return ToString(fmt, Globalization.CultureInfo.CurrentCulture)
End Function
Const ACCT_LENGTH = 12I
Public Overloads Function ToString(fmt As String, provider As IFormatProvider) _
As String Implements IFormattable.ToString
#If TRACE = trace_it Then
If provider Is Nothing Then Console.WriteLine($"fmt=({fmt}) Nothing <------------- provider")
#End If
Dim Bool_fmt As Boolean = fmt = "I" OrElse fmt = "H"
If Not Bool_fmt Then Return value.ToString() & " <----- format specifier not supported"
' Convert argument to a string.
Dim result As String = value.ToString()
' If account number is less than 12 characters, pad with leading zeroes.
If result.Length < ACCT_LENGTH Then result = result.PadLeft(ACCT_LENGTH, "0"c)
' If account number is more than 12 characters, truncate to 12 characters.
If result.Length > ACCT_LENGTH Then result = Left(result, ACCT_LENGTH)
If fmt = "I" Then ' Integer-only format.
Return result
' Add hyphens for H format specifier.
ElseIf fmt = "H" Then ' Hypenated format.
Return Left(result, 5) & "-" & Mid(result, 6, 3) & "-" & Right(result, 4)
End If
Return result
End Function
End Structure
Public Const Celsius_Str = " °C"
Public Const Fahrenheit_Str = " °F"
Public Const Kelvin_Str = " K"
Public Class Temperature
Implements IFormattable
Protected temp As Decimal
Public Sub New(Temperature As Decimal)
If Temperature < -273.15R Then
Throw New Exception($"{Temperature} is less than absolute zero.")
End If
Me.temp = Temperature
End Sub
Public ReadOnly Property Celsius As Decimal
Get
Return temp
End Get
End Property
Public ReadOnly Property Fahrenheit As Decimal
Get
Return temp * 9 / 5 + 32
End Get
End Property
Public ReadOnly Property Kelvin As Decimal
Get
Return temp + 273.15D
End Get
End Property
Public Overrides Function ToString() As String
Return Me.ToString("G", Globalization.CultureInfo.CurrentCulture)
End Function
Public Overloads Function ToString(format As String) As String
Return Me.ToString(format, Globalization.CultureInfo.CurrentCulture)
End Function
Public Overloads Function ToString(Format As String, provider As IFormatProvider) _
As String Implements IFormattable.ToString
If (String.IsNullOrEmpty(Format)) Then Format = "G"
If (provider Is Nothing) Then provider = Globalization.CultureInfo.CurrentCulture
Select Case (Format.ToUpperInvariant())
Case "G", "C"
Return Celsius.ToString("F2", provider) + Celsius_Str
Case "F"
Return Fahrenheit.ToString("F2", provider) + Fahrenheit_Str
Case "K"
Return Kelvin.ToString("F2", provider) + Kelvin_Str
Case Else
Throw New FormatException($"The {Format} format string is not supported.")
End Select
End Function
End Class
End Module
Public Class CultureInfomation_on_Windows
Implements IFormattable
Protected Cultures As Globalization.CultureInfo()
Public Sub New()
Me.Cultures = Globalization.CultureInfo.GetCultures(Globalization.CultureTypes.AllCultures)
End Sub
Public Overrides Function ToString() As String
Return Me.ToString("G", Globalization.CultureInfo.CurrentCulture)
End Function
Public Overloads Function ToString(Format As String, provider As IFormatProvider) _
As String Implements IFormattable.ToString
If (String.IsNullOrEmpty(Format)) Then Format = "G"
If (provider Is Nothing) Then provider = Globalization.CultureInfo.CurrentCulture
Select Case (Format.ToUpperInvariant())
Case "G", "W"
Dim Html_Str As New Text.StringBuilder("<!DOCTYPE html>
<html dir=""ltr"" , lang=""zh-tw"">
<head>
<meta charset=""utf-8"" />
<title>Cultures information on Windows</title>
</head>
<body>
<table>
<colgroup>
<col />
<col style=""background-color:chartreuse"" />
<col />
<col style=""background-color:chartreuse"" />
<col />
<col style=""background-color:chartreuse"" />
<col />
<col style=""background-color:chartreuse"" />
</colgroup>
<tr><th>index</th><th>LCID</th><th>Name</th><th>NativeName</th><th>IsNeutral</th><th>EnglishName</th></tr>
")
Dim index As Int32 = 0
For Each culture As Globalization.CultureInfo In Cultures
index += 1
Html_Str.Append(
$"<tr><td>{index}</td>
<td>{culture.LCID}</td>
<td>{culture.Name}</td>
<td>{culture.NativeName}</td>
<td>{culture.IsNeutralCulture}</td>
<td>{culture.EnglishName}</td>
</tr>")
Next
Html_Str.Append("</table></body></html>")
Return Html_Str.ToString
Case "C"
Dim Console_Str As New Text.StringBuilder()
Console_Str.AppendLine("index LCID Name" &
" NativeName NeutralCulture")
Dim index As Int32 = 0
For Each culture As Globalization.CultureInfo In Cultures
index += 1
Dim NativeName As String = culture.NativeName
Console_Str.AppendLine(
$"{index,5} {culture.LCID,5} {culture.Name,14} {NativeName,50} {culture.IsNeutralCulture,6}")
Next
Return Console_Str.ToString
Case Else
Throw New FormatException($"The {Format} format string is not supported.")
End Select
End Function
End Class