Q:

VB.NET Addin How do I select current worksheet

I'm trying to create an Excel VSTO Addin with VS2015 for a handful of VBA macros that I have.  I could do this using VBA, but want to get my feet wet in VB.NET.  The problem I'm facing though is how to get the active worksheet and assign it to a variable.  Then, I need to pass in a range that I converted to text previous.  
The macro essentially enables a user to compare two lists of data by selecting the ranges and then highlighting items that appear in both lists.

Here's the code that executes when a user tries to select the range (works fine)
    Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
    Try
        Me.Hide()
        Dim R As Microsoft.Office.Interop.Excel.Range
        Dim A As String
        'note how the Application.InputBox brings up different settings to just InputBox
        R = Globals.ThisAddIn.Application.InputBox(Prompt:="Please select the reference range", Type:=8)
        A = R.Address
        Me.TextBox1.Text = A
        Me.Show()
        Me.TopMost = True
        Exit Sub

    Catch
        MsgBox("Please select a valid range!")
        Me.Show()
    End Try
End Sub

Here's the code behind the "Search and Highlight" button, that should compare the two ranges and highlight duplicates.  However, when I run this it highlights cells in a different workbook, presumable the first one that I have open.  How do I make sure it's opening the current workbook that I'm operating in?
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click

    Dim xlApp As New Excel.Application
    Dim ws As Excel.Worksheet
    Dim sheetName As String
    Dim cell_1 As Excel.Range
    Dim cell_2 As Excel.Range
    Dim rng_1 As Excel.Range
    Dim rng_2 As Excel.Range

    xlApp = GetObject(, "Excel.Application")
    ws = xlApp.ActiveSheet
    sheetName = ws.Name

    rng_1 = ws.Range(Me.TextBox2.Text)
    rng_2 = ws.Range(Me.TextBox1.Text)

    For Each cell_1 In rng_1
        For Each cell_2 In rng_2
            If cell_2.Text = cell_1.Text Then
                cell_2.Interior.ColorIndex = 6

            End If
        Next cell_2
    Next cell_1

    Me.Close()

End Sub

A:

I found the answer, so I'm posting it for the next time I have to search for this. In the code below just make sure to change ThisAddIn to the name of your actual add-in.
    Dim wb As Excel.Workbook = Globals.ThisAddIn.Application.ActiveWorkbook
    Dim ws As Excel.Worksheet = Globals.ThisAddIn.Application.ActiveSheet

