Problems with Inputbox

[Josh704]

I want to make it so when cancel is used it exits the loop but I need the Input as a decimal. Thanks for any help.

Do

            txtItems.Text = intCounter.ToString

            intCounter = intCounter + 1

            msgInput = CDec(InputBox("Enter Item Price", "Item Price", ""))


            decSubTotal = msgInput + decSubTotal

            txtItemPrice.Text = msgInput.ToString("C2")



            txtSubTotal.Text = decSubTotal.ToString("C2")
            If msgInput = 0 Then
                Exit Do
            End If
        Loop

        decTax = CDec(decSubTotal * 0.065)

        decTotal = decTax + decSubTotal

        txtSalexTax.Text = decTax.ToString("C2")
        txtTotalSale.Text = decTotal.ToString("C2")

[jmcilhinney]

The primary problem with InputBox is that it exists. You should basically avoid using it if you possibly can. If you have to use it because the assignment says so, which I suspect is the case here, then you are stuck. Otherwise, you should create your own form that matches the rest of your UI and display it as a modal dialogue.

Assuming that you must use InputBox then here is some pseudo-code:

Do
    Call InputBox and get result

    If result is empty
        Exit Do
    Else
        Try to convert input to number and use as required
    End If
Loop

Unless you have been told that you can assume that the user input will always be a valid number, you should be using Decimal.TryParse to validate and convert rather than CDec, which will throw an exception if the data is not a valid number.

[Josh704]

The primary problem with InputBox is that it exists. You should basically avoid using it if you possibly can. If you have to use it because the assignment says so, which I suspect is the case here, then you are stuck. Otherwise, you should create your own form that matches the rest of your UI and display it as a modal dialogue.

Assuming that you must use InputBox then here is some pseudo-code:

Do
    Call InputBox and get result

    If result is empty
        Exit Do
    Else
        Try to convert input to number and use as required
    End If
Loop

Unless you have been told that you can assume that the user input will always be a valid number, you should be using Decimal.TryParse to validate and convert rather than CDec, which will throw an exception if the data is not a valid number.

Thank you very much, yeah I was gonna go back and use tryparse to validate it after I finished most of it.

[Josh704]

Could I somehow convert it all to a decimal after the string goes in?

[jmcilhinney]

Could I somehow convert it all to a decimal after the string goes in?

That's what Decimal.TryParse does.

[Josh704]

If I put the tryparse before this then it would convert it to a decimal before?

msgInput = CDec(InputBox("Enter Item Price", "Item Price", ""))

[jmcilhinney]

How could you put the TryParse before that line when that line is the one that gets the user input? All you have to do is read my pseudo-code and do what it says. Get the input first, then check whether it's empty, then try to convert it if it's not.

[Josh704]

How could you put the TryParse before that line when that line is the one that gets the user input? All you have to do is read my pseudo-code and do what it says. Get the input first, then check whether it's empty, then try to convert it if it's not.

Yeah I see what your saying, I ended up figuring it out though. Thank you for the help!