Public Class Form1
Dim Licens_Dealer() As String = {"aa", "bbb", "ccc"}


Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
Dim Input_txt_length As Integer
Dim Input_txt As String
Dim Dealer_txt_length As Integer
Dim Dealer_txt As String
Dim myC As Integer = 0
Input_txt_length = TextBox1.TextLength
Input_txt = TextBox1.Text
Dim myStr As String

For Each str As String In Licens_Dealer
Dealer_txt = Licens_Dealer(myC).ToString
Dealer_txt_length = Dealer_txt.Length

myC += 1
myStr = Mid(Input_txt, 1, Dealer_txt_length)
Label1.Text = Dealer_txt
Label2.Text = myStr & " " & Dealer_txt_length
If Dealer_txt = myStr Then
MsgBox(myStr)
Else
MsgBox("NO")
End If
Next
End Sub


End Class