Visual basic 2003: Convert 'String' to 'Double'

I'm trying to do deployment with strict on.
However, editstudCourse Fee.text is giving me error="option strict on disallows implicit conversions from string to double."
Hope someone can shed some light on this.

    Dim TaxValue As Double = 5
    Dim TaxValueContainer As String

    Dim courseFee As Double = 0
    Dim courseFeeContainer As String

    Dim TaxDisplay As Double
    Dim TaxValueInput As Double
    'Dim noContainer As String
    Dim no1, no2, no3, no4 As Double

...continue

   editstudTaxAmount.Text = editstudCourseFee.Text * TaxValue / 100   <--How to convert editstudCourseFee.Text from 'string' to 'double'
            no1 = Double.Parse(editstudCourseFee.Text)
            no2 = Double.Parse(editstudTaxAmount.Text)
            editstudTotalPayable.Text = Round(no1 + no2, 2).ToString

            no3 = Double.Parse(editstudTotalPayable.Text)
            no4 = Double.Parse(editstudTotalPaid.Text)
            editstudTotalBalance.Text = Round(no3 - no4).ToString