If Statement isn’t evaluating out correctly
I am trying to learn VB.Net using VB Studio 2005 Express edition and a pretty good text book. I thought I was beginning to understand concepts until this exercise came up - now I wonder... No matter what value I put into txtOrderTotal.Text, I get the same dDiscountTotal... This is 'hand-fed' code that is directly entered from the textbook (and I verified accuracy). Is it maybe something to do with the text-to-decimal change? Here is the code:
Dim dOrderTotal As Decimal
Dim dDiscountPct As Decimal
Dim dDiscountAmount As Decimal
Dim dInvoiceTotal As Decimal
dOrderTotal = txtOrderTotal.Text
If dOrderTotal >= 500 Then
dDiscountPct = 0.2
ElseIf dOrderTotal >= 250 And dOrderTotal < 500 Then
dDiscountPct = 0.15
ElseIf dOrderTotal >= 100 And dOrderTotal < 250 Then
dDiscountPct = 0.1
Else
dDiscountPct = 0
End If
dDiscountAmount = dOrderTotal * dDiscountPct
dInvoiceTotal = dOrderTotal - dDiscountAmount
lblDiscountAmount.Text = dDiscountAmount
lblInvoiceTotal.Text = dInvoiceTotal
txtOrderTotal.Focus()
Thanks in advance for any assistance,
R Brown
Software/Hardware used:
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ASKED:
April 21, 2009 8:00 PM
UPDATED:
April 23, 2009 12:03 PM
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Answer Wiki:
Guys,
I figured it out... the conditions weren't being defined well enough for the 'between' values. Here are the changes I made to the If...Then... Else statements:
If dOrderTotal >= 500 Then
dDiscountPct = 0.2
ElseIf dOrderTotal >= 250 And dOrderTotal < 500 Then
dDiscountPct = 0.15
ElseIf dOrderTotal >= 100 And dOrderTotal < 250 Then
dDiscountPct = 0.1
Else '(dDiscountPct < 100)
dDiscountPct = 0
End If
I appreciate all of your assistance - you guys got me to thinking a little more clearly.
Ruth
To see all answers submitted to the Answer Wiki: View Answer History.
And, what value are you getting for dDiscountTotal ?
When you say “No matter what value I put into txtOrderTotal.Text, I get the same dDiscountTotal”, you mean that you are entering values in the txtOrderTotal box at runtime, right ? Or are you trying assigning values to it programmatically ?
I have just created a test project with a text box, two labels and a button, and copied your code, and it works ok for me.
The code does look like it works. Do you mean lblDiscountAmount.Text = dDiscountAmount or lblInvoiceTotal.Text doesn’t change?
I will try to give a little better answer about what I am seeing… When I go into Runtime, no matter what value I enter for txtOrderTotal.Text, I get the same dDiscountTotal.
If I put in 550 for txtOrderTotal.Text, I should see a 20% discount. If I put in 300, I should get a 15% discount. If I put in 100, I should see a 10% discount. Less than 100 should get no discount.
What I am seeing is that for any OrderTotal (500, 300, 100, 50) I get the same 20% discount. It’s like the code is ignoring the additional statements. Just reading through the code, it looks like it should work, but I am working on my first true exercise in this textbook and am probably overlooking something. That’s why I asked about the use of the .text ending on the txtOrderTotal.text – could it not be converting the text to number correctly? I even tried it using the Select Case method & got the same thing…
I really appreciate you guys trying to help me out.
Ruth
I’m glad you figured it out, and thanks for sharing, but I don’t see the difference with the original code.
The only difference in the code is that I added a ‘between’ value. Before, it only had > or >= values. I added the < value for the in between numbers that need to be >= one and < the other. I guess what made me think to try it was the fact that I have to do that when I code VBA in Access…
Ruth