getting value or output result of an system calculator in vb.net textbox

Looks to be mildly complicated.

Try the answers at https://social.msdn.microsoft.com/Forums/en-US/e9b2c76c-c96e-46a8-b5cc-d26798e831ae/get-windows-calc-values-using-vbnet?forum=isvvba

Perhaps you'd like to emply 'mates8.dll' (in the attached file there is an example). There needs to be a reference to the dll and the imports statement. Then, you may parse simple expressions calling the Expression.parseExpression method.

Imports m8 = mates8

Public Class Form1

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles btnCalculate.Click
        Try
             Dim expr As m8.Expression = m8.Expression.parseExpression(tBoxExpression.Text)
            tBoxResult.Text = expr.ToString
        Catch ex As Exception

        End Try
    End Sub
End Class

Sorry, the original file was not attached.

You can do it using AutoIt (free). If you create the AutoItX object within your program you can get the value in the calculator by

calc = "Calculator"

If aut.WinExists(calc) Then
    result = aut.WinGetText(calc)
Else
    MsgBox(calc & " window not found")
End If