Multiple text box prob

[JENKINS]

I am trying to make a login program that uses number buttons instead of the keyboard. the program has ten number buttons(like a keypad), I can't seem to figure out how to get the number buttons to put data into the text box that is CURRENTLY SELECTED. If textBoxID was selected and then I entered some numbers, when I select the PinTextBox the numbers still go into the textBoxID, here's the entire code:

Public Class Form7
    Inherits System.Windows.Forms.Form
    Dim strPinNumber, strIDNumber As String

  Private Sub ButtonBack_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ButtonBack.Click
        Dim f1 As New Form1
        f1.Show()
        Me.Hide()
    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        strPinNumber += "1"
        strIDNumber += "1"

        If TextBoxAccountID.SelectionStart Then
            TextBoxAccountID.Text = strIDNumber
        Else
            TextBoxPinNumber.Text = strPinNumber
        End If
    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        strPinNumber += "2"
        strIDNumber += "2"

        If TextBoxAccountID.SelectionStart Then
            TextBoxAccountID.Text = strIDNumber
        Else
            TextBoxPinNumber.Text = strPinNumber
        End If
    End Sub

    Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
        strPinNumber += "3"
        strIDNumber += "3"

        If TextBoxAccountID.SelectionStart Then
            TextBoxAccountID.Text = strIDNumber
        Else
            TextBoxPinNumber.Text = strPinNumber
        End If
    End Sub

    Private Sub Button4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click
        strPinNumber += "5"
        strIDNumber += "5"

        If TextBoxAccountID.SelectionStart Then
            TextBoxAccountID.Text = strIDNumber
        Else
            TextBoxPinNumber.Text = strPinNumber
        End If

    End Sub

    Private Sub Button5_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button5.Click
        strPinNumber += "6"
        strIDNumber += "6"

        If TextBoxAccountID.SelectionStart Then
            TextBoxAccountID.Text = strIDNumber
        Else
            TextBoxPinNumber.Text = strPinNumber
        End If
    End Sub

    Private Sub Button6_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button6.Click
        strPinNumber += "7"
        strIDNumber += "7"

        If TextBoxAccountID.SelectionStart Then
            TextBoxAccountID.Text = strIDNumber
        Else
            TextBoxPinNumber.Text = strPinNumber
        End If

    End Sub

    Private Sub Button7_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button7.Click
        strPinNumber += "7"
        strIDNumber += "7"

        If TextBoxAccountID.SelectionStart Then
            TextBoxAccountID.Text = strIDNumber
        Else
            TextBoxPinNumber.Text = strPinNumber
        End If
    End Sub

    Private Sub Button8_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button8.Click
        strPinNumber += "8"
        strIDNumber += "8"

        If TextBoxAccountID.SelectionStart Then
            TextBoxAccountID.Text = strIDNumber
        Else
            TextBoxPinNumber.Text = strPinNumber
        End If
    End Sub

    Private Sub Button9_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button9.Click
        strPinNumber += "9"
        strIDNumber += "9"

        If TextBoxAccountID.SelectionStart Then
            TextBoxAccountID.Text = strIDNumber
        Else
            TextBoxPinNumber.Text = strPinNumber
        End If
    End Sub

    Private Sub Button0_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button0.Click
        strPinNumber += "0"
        strIDNumber += "0"

        If TextBoxAccountID.SelectionStart Then
            TextBoxAccountID.Text = strIDNumber
        Else
            TextBoxPinNumber.Text = strPinNumber
        End If
    End Sub

    Private Sub ButtonLogin_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ButtonLogin.Click

    End Sub

    Private Sub ButtonClearText_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ButtonClearText.Click

        If TextBoxAccountID.SelectionStart Then
            TextBoxAccountID.Text = Mid(TextBoxAccountID.Text, 1, TextBoxAccountID.Text.Length - 1)
            strIDNumber = strIDNumber.Substring(0, strIDNumber.Length - 1)
        Else
            TextBoxPinNumber.Text = Mid(TextBoxPinNumber.Text, 1, TextBoxPinNumber.Text.Length - 1)
            strPinNumber = strPinNumber.Substring(0, strPinNumber.Length - 1)

        End If
    End Sub
End Class