VB.NET- Changing .Text property of Textbox throws Null Reference Exception - nullreferenceexception

Question

This MUST be trivial. I do this for a living and CAN NOT figure out why I am getting this exception:
System.NullReferenceException was unhandled Message=Object reference
not set to an instance of an object.
Here is the code:
Public Class frmMain
Private Sub frmMain_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim counties() As String
counties = {"", "Huntsville, AL", "Madison, AL", "Rural Madison County, AL", "Taft, TN"}
Me.cbCounties.DataSource = counties
Me.lblStatus.Text = "[ Please select a county ]"
Me.lblStatus.Left = Me.ClientSize.Width \ 2 - Me.lblStatus.Width \ 2
End Sub
Private Sub cbCounties_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cbCounties.SelectedIndexChanged
Select Case cbCounties.SelectedIndex
Case 1
txtTaxRate.Text = "8.00%" 'Issue is these, when index is changed.
Case 2
txtTaxRate.Text = "8.50%"
Case 3
txtTaxRate.Text = "5.50"
Case 4
txtTaxRate.Text = "9.50%"
Case Else
txtTaxRate.Text = Nothing
End Select
Me.lblStatus.Text = "[ Please enter net amount ]"
Me.lblStatus.Left = Me.ClientSize.Width \ 2 - Me.lblStatus.Width \ 2
End Sub
End Class
Help?

Answer 1

Is this after you changed it a couple of times?
Setting txtTaxRate = Nothing and later trying to set txtTaxRate.Text to something else will cause some problems.
You are setting the textbox object to nothing, and later trying to reference one of its properties.
Try changing
txtTaxRate = Nothing
to
txtTaxRate.Text = ""