Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim numtoDisturbute As String
numtoDisturbute = Trim(txtSource.Text)
If numtoDisturbute.Length = 0 Then Exit Sub
Dim arr As New List(Of String)
For Each Cha As Char In numtoDisturbute
arr.Add(Cha)
Next
For i As Integer = 0 To arr.Count - 1
Dim text As String = arr.Item(i)
Select Case i
Case 0
TextBox1.Text = text
Case 1
TextBox2.Text = text
Case 2
TextBox3.Text = text
Case 3
TextBox4.Text = text
End Select
Next
End Sub