Изменить формат времени с 20:30 на 20.5

Result = Format(Now,"HH." & 100/60*CInt"mm")

Public Class Form1
 
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Dim Result
        Result = Format(Now, "HH." & 100 / 60 * CInt("mm"))
        MsgBox(Result.ToString)
    End Sub
End Class

Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
        Dim Result As String = Format(Now, "HH." & Math.Round(100 / 60 * Format(Now, "mm")))
        MsgBox(Format(Now, "HH:mm = ") & Result)
    End Sub

Dim Result As String = Format(Now, "HH." & Math.Round(100 / 60 * (Format(Now, "mm")) + (Format(Now, "ss") / 100)))
Text = Format(Now, "HH:mm = ") & Result

Dim Result As String = Format(Now, "HH." & Math.Round(100 / 60 * (Format(Now, "mm")) + Math.Round(100 / 60 * (Format(Now, "ss") / 100))))

Sub Main()
    Console.WriteLine(TimeToDouble(DateTime.Parse("20:30")))
    Console.WriteLine("{0:hh\:mm}", DoubleToTime(20.5))
    Console.Read()
End Sub
''' <summary>
''' Перевод часов в дробное число
''' </summary>
Private Function TimeToDouble(time As DateTime) As Double
    Dim d = New DateTime(time.Year, time.Month, time.Day)
    Return (time - d).TotalHours
End Function
''' <summary>
''' Перевод дробного числа в часы
''' </summary>
Private Function DoubleToTime(val As Double) As TimeSpan
    Dim d As New DateTime(DateTime.Now.Year, DateTime.Now.Month, DateTime.Now.Day)
    Return d.AddHours(val) - d
End Function

Textbox2.Text = TimeToDouble(DateTime.Parse(Textbox1.Text))
 
 
'Перевод часов в дробное число
Private Function TimeToDouble(time As DateTime) As Double
    Dim d = New DateTime(time.Year, time.Month, time.Day)
    Return (time - d).TotalHours
End Function

TextBox2.Text = Split(TextBox1.Text, ":")(0) & "." & Math.Round(100 / 60 * Split(TextBox1.Text, ":")(1))

TextBox2.Text = TimeSpan.Par se(TextBox1.Texte).TotalHours.ToString()