Update TextBox wile in Background Worker : **Unable to update textbox value while in background worker,
value to be updated is sum of column("TaxableValue") of a datatable created inside background worker.**

On Button Click following event is raised


    Private Sub btnCalcTax_Click(sender As Object, e As EventArgs) Handles btnCalcTax.Click        
            BackgroundWorker1.RunWorkerAsync()
        End Sub

I have created a function to calculate TAX.
    
      Public Function TAXCALC
        Dim taxcalcdt As New DataTable

        'Code For Calculating Tax Begins.
                 ......
        'Code For Calculating Tax End.

        TextBox1.Text = taxcalcdt.Compute("Sum(TaxableValue)", String.Empty).ToString
      End Sub
I am unable to update sum of column("TaxableValue") to Textbox1.text

Code For BackgroundWorker_DoWork is

        Private Sub BackgroundWorker1_DoWork(sender As Object, e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork
                TAXCALC()
     End Sub
