need help, newbie here

ok, so I am not sure what I'm doing wrong. I wrote this code for an assignment and it is giving me this error: Conversion from string "" to type 'Double' is not valid...on this line r = CDbl(txtResthr.Text)

Here is the full program:

Public Class Form1

Private Sub txtAge_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles txtAge.TextChanged

End Sub

Private Sub txtResthr_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles txtResthr.TextChanged

End Sub

Private Sub btnCompute_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCompute.Click
Dim a, r As Double
Dim trainingheartrate As Double
a = CDbl(txtAge.Text)
r = CDbl(txtResthr.Text)
trainingheartrate = 0.7 * (220 - a) + 0.3 * r
trainingheartrate = Math.Round(trainingheartrate, 1)
txtTrainhr.Text = "Your THR is" & trainingheartrate & " beats per minute"
End Sub

Private Sub txtTrainhr_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles txtTrainhr.TextChanged

End Sub

End Class

Can someone point me in the right direction? Thanks!!

Comments

Sign In or Register to comment.

Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!

Categories

In this Discussion