How to handle extra space in result in textbox in vb.net

I'm Trying to handle extra space in result in textbox in vb.net

Is there something wrong with my code?

or there is another solution?

Please Guide me

Thanks

Below is the code I used :

Public Class Form6
    Public Function Terbilang(ByVal nilai As Integer) As String
        Dim bilangan As String() = {"", "Satu", "Dua", "Tiga", "Empat", "Lima", "Enam", "Tujuh", "Delapan", "Sembilan", "Sepuluh", "Sebelas"}
        If nilai < 12 Then
            Return " " & System.Text.RegularExpressions.Regex.Replace(bilangan(CInt(nilai)), "^\s+|\s+$", " ")
        ElseIf nilai < 20 Then
            Return System.Text.RegularExpressions.Regex.Replace(Terbilang(nilai - 10) & " Belas", "^\s+|\s+$", " ")
        ElseIf nilai < 100 Then
            Return System.Text.RegularExpressions.Regex.Replace((Terbilang(CInt((nilai \ 10))) & " Puluh") + Terbilang(nilai Mod 10), "^\s+|\s+$", " ")
        ElseIf nilai < 200 Then
            Return System.Text.RegularExpressions.Regex.Replace(" Seratus" & Terbilang(nilai - 100), "^\s+|\s+$", " ")
        ElseIf nilai < 1000 Then
            Return System.Text.RegularExpressions.Regex.Replace((Terbilang(CInt((nilai \ 100))) & " Ratus") + Terbilang(nilai Mod 100), "^\s+|\s+$", " ")
        ElseIf nilai < 2000 Then
            Return System.Text.RegularExpressions.Regex.Replace(" Seribu" & Terbilang(nilai - 1000), "^\s+|\s+$", " ")
        ElseIf nilai < 1000000 Then
            Return System.Text.RegularExpressions.Regex.Replace((Terbilang(CInt((nilai \ 1000))) & " Ribu") + Terbilang(nilai Mod 1000), "^\s+|\s+$", " ")
        ElseIf nilai < 1000000000 Then
            Return System.Text.RegularExpressions.Regex.Replace((Terbilang(CInt((nilai \ 1000000))) & " Juta") + Terbilang(nilai Mod 1000000), "^\s+|\s+$", " ")
        ElseIf nilai < 1000000000000 Then
            Return System.Text.RegularExpressions.Regex.Replace((Terbilang(CInt((nilai \ 1000000000))) & " Milyar") + Terbilang(nilai Mod 1000000000), "^\s+|\s+$", " ")
        ElseIf nilai < 1000000000000000 Then
            Return System.Text.RegularExpressions.Regex.Replace((Terbilang(CInt((nilai \ 1000000000000))) & " Trilyun") + Terbilang(CInt(nilai Mod 1000000000000)), "^\s+|\s+$", " ")
        Else
            Return ""
        End If
    End Function
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        TextBox2.Text = Terbilang(CInt(TextBox1.Text))
    End Sub
End Class

Below are examples of problems with extra space :

Example 1
Input	350000
Output	`Tiga Ratus Lima Puluh Ribu Rupiah`
Expected	`Tiga Ratus Lima Puluh Ribu Rupiah`

Example 2
Input	20000
Output	`Dua Puluh Ribu Rupiah`
Expected	`Dua Puluh Ribu Rupiah`

Example 3
Input	100
Output	`Seratus Rupiah`
Expected	`Seratus Rupiah`

After updated code from @AndrewMorton

Example 1
Input	350000
Output	`Tiga Ratus Lima Puluh Ribu Rupiah`
Expected	`Tiga Ratus Lima Puluh Ribu Rupiah`

Example 2
Input	20000
Output	`Dua Puluh Ribu Rupiah`
Expected	`Dua Puluh Ribu Rupiah`

Only example 3 solved

Example 3
Input	100
Output	`Seratus Rupiah`
Expected	`Seratus Rupiah`

Update code recommendation from @WiktorStribiżew

Public Function Terbilang(ByVal nilai As Integer) As String
        Dim bilangan As String() = {"", "Satu", "Dua", "Tiga", "Empat", "Lima", "Enam", "Tujuh", "Delapan", "Sembilan", "Sepuluh", "Sebelas"}
        If nilai < 12 Then
            Return Trim(bilangan(CInt(nilai)))
        ElseIf nilai < 20 Then
            Return Trim(Terbilang(nilai - 10) & " Belas")
        ElseIf nilai < 100 Then
            Return Trim(Terbilang(CInt((nilai \ 10))) & " Puluh" + Terbilang(nilai Mod 10))
        ElseIf nilai < 200 Then
            Return Trim(" Seratus" & Terbilang(nilai - 100))
        ElseIf nilai < 1000 Then
            Return Trim(Terbilang(CInt((nilai \ 100))) & " Ratus" + Terbilang(nilai Mod 100))
        ElseIf nilai < 2000 Then
            Return Trim(" Seribu" & Terbilang(nilai - 1000))
        ElseIf nilai < 1000000 Then
            Return Trim(Terbilang(CInt((nilai \ 1000))) & " Ribu" + Terbilang(nilai Mod 1000))
        ElseIf nilai < 1000000000 Then
            Return Trim(Terbilang(CInt((nilai \ 1000000))) & " Juta" + Terbilang(nilai Mod 1000000))
        ElseIf nilai < 1000000000000 Then
            Return Trim(Terbilang(CInt((nilai \ 1000000000))) & " Milyar" + Terbilang(nilai Mod 1000000000))
        ElseIf nilai < 1000000000000000 Then
            Return Trim(Terbilang(CInt((nilai \ 1000000000000))) & " Trilyun" + Terbilang(CInt(nilai Mod 1000000000000)))
        Else
            Return ""
        End If
    End Function
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        TextBox2.Text = Trim(Terbilang(CInt(TextBox1.Text)) + " Rupiah")
    End Sub

so only example 1 is unsolved and Others Solved

Example 1
Input	350000
Output	`Tiga RatusLima Puluh Ribu Rupiah`
Expected	`Tiga Ratus Lima Puluh Ribu Rupiah`

Solution

Getting the white spaces right is not that trivial. Therefore, I suggest building the result in a List(Of String) and then join the result with a white space as separator.

I split the task in a main function initializing the list, calling a Sub doing the calculation and joining the result:

Public Function Terbilang(ByVal nilai As Long) As String
    Dim result = New List(Of String)

    TerbilangRecursive(result, nilai)
    Return String.Join(" ", result)
End Function

The calculation happens in a recursive Sub. It is passed the result list where it can add elements and the value as parameter.

Private Sub TerbilangRecursive(result As List(Of String), nilai As Long)
    Static bilangan As String() = {"", "Satu", "Dua", "Tiga", "Empat", "Lima",
        "Enam", "Tujuh", "Delapan", "Sembilan", "Sepuluh", "Sebelas"}

    If nilai < 12 Then
        If nilai > 0 Then ' Do not add an empty entry
            result.Add(bilangan(nilai))
        End If
    ElseIf nilai < 20 Then
        TerbilangRecursive(result, nilai - 10)
        result.Add("Belas")
    ElseIf nilai < 100 Then
        TerbilangRecursive(result, nilai \ 10)
        result.Add("Puluh")
        TerbilangRecursive(result, nilai Mod 10)
    ElseIf nilai < 200 Then
        result.Add("Seratus")
        TerbilangRecursive(result, nilai - 100)
    ElseIf nilai < 1_000 Then
        TerbilangRecursive(result, nilai \ 100)
        result.Add("Ratus")
        TerbilangRecursive(result, nilai Mod 100)
    ElseIf nilai < 2_000 Then
        result.Add("Seribu")
        TerbilangRecursive(result, nilai - 1_000)
    ElseIf nilai < 1_000_000 Then
        TerbilangRecursive(result, nilai \ 1_000)
        result.Add("Ribu")
        TerbilangRecursive(result, nilai Mod 1_000)
    ElseIf nilai < 1_000_000_000 Then
        TerbilangRecursive(result, nilai \ 1_000_000)
        result.Add("Juta")
        TerbilangRecursive(result, nilai Mod 1_000_000)
    ElseIf nilai < 1_000_000_000_000 Then
        TerbilangRecursive(result, nilai \ 1_000_000_000)
        result.Add("Milyar")
        TerbilangRecursive(result, nilai Mod 1_000_000_000)
    ElseIf nilai < 1_000_000_000_000_000 Then
        TerbilangRecursive(result, nilai \ 1_000_000_000_000)
        result.Add("Trilyun")
        TerbilangRecursive(result, nilai Mod 1_000_000_000_000)
    Else
        ' No action
    End If
End Sub

A few things to note:

I made the bilangan array with the Indonesian number names Static. This means that this array will be created and initialized only once instead of at each call of the Sub.
You are using numbers which exceed the maximum range of Integer which is roughly 2 billions. Therefore I am using the 64 bit type Long having a maximum of about 9.22 * 10^18 instead of the 32 bit Integer type.
Integer division \ already returns a truncated integer value. Therefore, there is no need to use CInt(...) or CLng(...).
We must take care not to add the empty "" for the zero digit.
Some numbers are very long. Starting with Visual Basic 2017, we can use the underscore character _ as a digit separator to enhance readability. I used it as thousands separator.

As test setup I used this routine in a Console application:

Sub Test()
    Dim examples As (value As Long, expected As String)() = {
        (350_000, "Tiga Ratus Lima Puluh Ribu Rupiah"),
        (20_000, "Dua Puluh Ribu Rupiah"),
        (100, "Seratus Rupiah")}

    For Each example In examples
        Console.WriteLine($"Value = {example.value}")
        Console.WriteLine($"Expected = {example.expected}")
        Console.WriteLine($"> Result = {Terbilang(example.value)} Rupiah")
        Console.WriteLine()
    Next
    Console.ReadKey()
End Sub

It creates an example array of Tuples with an input value and the expected result and then executes every example in a loop. I am also using Interpolated Strings. It produces the following output:

Value = 350000
Expected = Tiga Ratus Lima Puluh Ribu Rupiah
> Result = Tiga Ratus Lima Puluh Ribu Rupiah

Value = 20000
Expected = Dua Puluh Ribu Rupiah
> Result = Dua Puluh Ribu Rupiah

Value = 100
Expected = Seratus Rupiah
> Result = Seratus Rupiah