C#•2w ago

Workshop calculate not working

Here is my code both in form1 and designer. I know I messed up and had a dislexic moment and switched two words around but when i try to fix it, it gives me errors. But I also cant get the calculate button to work when running the program. I just cant seem to get these assignments with calculations to work. https://paste.mod.gg/eykezrwgbwdh/0

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54 Replies

Pobiega•2w ago

Can you be more specific about what doesnt work and how it doesnt? ie, what is the expected result, and what are you seeing I'm seeing some unusual variable names thou, that might cause some confusion..

        double dayslabel;
        double registrationFeeLabel;
        double lodgingFeeLabel;

        double dayslabel;
        double registrationFeeLabel;
        double lodgingFeeLabel;

these are just variables for storing floating point numbers, they are in no way connected to their respective labels also, all those variables are declared in the class member scope, but are only ever used as local variables in the calculateButton_Click method @Nightswyng

NightswyngOP•2w ago

Apologies had to step away

NightswyngOP•2w ago

so, i deleted the errors, but when I had the label double lodgingTotalLabel it is showing as unused

NightswyngOP•2w ago

when i tried to change it to the totalLodgingLabel it would give me an error

Pobiega•2w ago

All those variables are declared in the wrong place, if you ask me. Every single one.

NightswyngOP•2w ago

Pobiega•2w ago

And that switch is a mess too :p set the value with a switch expression, then update the label afterwards will cut that down a lot in size and complexity

NightswyngOP•2w ago

I am not sure what you mean

Pobiega•2w ago

before

switch (selectedLocation)
{
    case "Austin":
        lodgingFeeLabel = 150;
        totalLodgingLabel.Text = "$150";
        break;
    case "Chicago":
        lodgingFeeLabel = 225;
        totalLodgingLabel.Text = "$225";
        break;
    case "Dallas":
        lodgingFeeLabel = 175;
        totalLodgingLabel.Text = "$175";
        break;
    case "Orlando":
        lodgingFeeLabel = 300;
        totalLodgingLabel.Text = "$300";
        break;
    case "Phoenix":
        lodgingFeeLabel = 175;
        totalLodgingLabel.Text = "$175";
        break;
    case "Raleigh":
        lodgingFeeLabel = 150;
        totalLodgingLabel.Text = "$150";
        break;
}

switch (selectedLocation)
{
    case "Austin":
        lodgingFeeLabel = 150;
        totalLodgingLabel.Text = "$150";
        break;
    case "Chicago":
        lodgingFeeLabel = 225;
        totalLodgingLabel.Text = "$225";
        break;
    case "Dallas":
        lodgingFeeLabel = 175;
        totalLodgingLabel.Text = "$175";
        break;
    case "Orlando":
        lodgingFeeLabel = 300;
        totalLodgingLabel.Text = "$300";
        break;
    case "Phoenix":
        lodgingFeeLabel = 175;
        totalLodgingLabel.Text = "$175";
        break;
    case "Raleigh":
        lodgingFeeLabel = 150;
        totalLodgingLabel.Text = "$150";
        break;
}

after

lodgingFee = selectedLocation switch
{
    "Austin" => 150,
    "Chicago" => 225,
    "Dallas" => 175,
    "Orlando" => 300,
    "Phoenix" => 175,
    "Raleigh" => 150,
    _ => throw new ArgumentOutOfRangeException() // Invalid location selected
};
totalLodgingLabel.Text = $"${lodgingFee}";

lodgingFee = selectedLocation switch
{
    "Austin" => 150,
    "Chicago" => 225,
    "Dallas" => 175,
    "Orlando" => 300,
    "Phoenix" => 175,
    "Raleigh" => 150,
    _ => throw new ArgumentOutOfRangeException() // Invalid location selected
};
totalLodgingLabel.Text = $"${lodgingFee}";

which one is easier to read and maintain?

NightswyngOP•2w ago

the second one is alot cleaner can you explain that last line $"${lodgingFee}";

Pobiega•2w ago

sure, the first dollar sign is BEFORE the string quotation mark

Pobiega•2w ago

that means that string is using string interpolation

$ - string interpolation - format string output - C# reference

String interpolation using the $ token provides a more readable and convenient syntax to format string output than traditional string composite formatting.

Pobiega•2w ago

a fancy way of saying, I want to "inject" some variables into the string think of {lodgingFee} as a placeholder that will be replaced with the value of lodingFee so it becomes $150 for example

NightswyngOP•2w ago

if i throw it in to VS, I would have to rewrite everything because its giving me so many errors, so how do I clean this up to work? also with the current code, when I run the program and select each item, hit calculate nothing works or shows up in the 4 boxes Am I using the wrong thing(label)?

Pobiega•2w ago

I can't tell, because you didn't show that part of the code oh you did, you just didnt give it a filename. okay I see lemme look I don't see any binding to the click event

NightswyngOP•2w ago

oh wow I see that now, there is no event

Pobiega•2w ago

ie, your button doesnt actually invoke the method

NightswyngOP•2w ago

how did that happen?

Pobiega•2w ago

¯\_(ツ)_/¯ also, I think you have several calculation issues too totalCost = lodgingFeeLabel * registrationFeeLabel; doesn't seem right lodingfee TIMES registrationfee? also, you update theactual lodgingfee label twice both in the switch, with hardcoded values, then later with the calculated one (* days) but ppleeease rename your variables lol daysLabel is a baaad name. numberOfDays is muuuch better

NightswyngOP•2w ago

I was going off the directions and previous instruction I will change it

Pobiega•2w ago

oh, and also look at this beauty

var (numberOfDays, registrationFee) = selectedWorkshop switch
{
    "Handling Stress" => (3, 1000),
    "Time Management" => (3, 800),
    "Supervision Skills" => (3, 1500),
    "Negotiation" => (5, 1300),
    "How to Interview" => (1, 500),
    _ => throw new ArgumentOutOfRangeException() // Invalid workshop selected
};

var (numberOfDays, registrationFee) = selectedWorkshop switch
{
    "Handling Stress" => (3, 1000),
    "Time Management" => (3, 800),
    "Supervision Skills" => (3, 1500),
    "Negotiation" => (5, 1300),
    "How to Interview" => (1, 500),
    _ => throw new ArgumentOutOfRangeException() // Invalid workshop selected
};

🤤 switch expressions :catlove:

NightswyngOP•2w ago

so when I put that in, it was telling me there was an error with the underscore

Pobiega•2w ago

what error?

NightswyngOP•2w ago

CS 7.3 and using something higher than 8.0

Pobiega•2w ago

oh, you made the project using .NET framework 4.x not modern .NET 9

NightswyngOP•2w ago

yea, that was what I was told to use

Pobiega•2w ago

For shame.

NightswyngOP•2w ago

still learning the difference

Pobiega•2w ago

Your teachers are bad and should feel bad. .NET framework "died" in 2016 I can see schools not updating directly and still teaching old stuff for a few years, but 9 whole years?

NightswyngOP•2w ago

I think thats why i am struggling, alot of the resources are showing different versions

Pobiega•2w ago

Most resources online will assume modern .NET versions these days again, it has been 9 years.

NightswyngOP•2w ago

I will schedule a zoom meeting with my professor to clarify since we are going of the book, I don't want to be outdated in my learning

Pobiega•2w ago

I think the book is in fact using the old version thou, unless I am remembering wrong

NightswyngOP•2w ago

But pointing out there was no events in the designer helped immensely and it works!

Pobiega•2w ago

We talked about this on your last thread, I think

NightswyngOP•2w ago

You are correct, we did discuss that last time

Pobiega•2w ago

so just to recap, if I were to write this, it'd be something like...

private void calculateButton_Click(object sender, EventArgs e)
{
    if (workshopListBox.SelectedIndex == -1)
    {
        // If none selected
        MessageBox.Show("Select a Workshop, Please.");
        return; // we can't continue if no workshop is selected
    }
    
    if (locationListBox.SelectedIndex == -1)
    {
        // If no location selected
        MessageBox.Show("Select a Location, Please.");
        return;
    }

    var selectedWorkshop = workshopListBox.SelectedItem.ToString();
    
    var (numberOfDays, registrationFee) = selectedWorkshop switch
    {
        "Handling Stress" => (3, 1000),
        "Time Management" => (3, 800),
        "Supervision Skills" => (3, 1500),
        "Negotiation" => (5, 1300),
        "How to Interview" => (1, 500),
        _ => throw new ArgumentOutOfRangeException() // Invalid workshop selected
    };
    
    totalDaysLabel.Text = numberOfDays.ToString();
    feeOutputLabel.Text = registrationFee.ToString("c");

    var selectedLocation = locationListBox.SelectedItem.ToString();

    var lodgingFee = selectedLocation switch
    {
        "Austin" => 150,
        "Chicago" => 225,
        "Dallas" => 175,
        "Orlando" => 300,
        "Phoenix" => 175,
        "Raleigh" => 150,
        _ => throw new ArgumentOutOfRangeException() // Invalid location selected
    };

    // Calculate Lodging cost
    lodgingFee = numberOfDays * lodgingFee;
    totalLodgingLabel.Text = lodgingFee.ToString("c");

    // Calculate Total cost
    var totalCost = lodgingFee + registrationFee;
    totalCostLabel.Text = totalCost.ToString("c");
}

private void calculateButton_Click(object sender, EventArgs e)
{
    if (workshopListBox.SelectedIndex == -1)
    {
        // If none selected
        MessageBox.Show("Select a Workshop, Please.");
        return; // we can't continue if no workshop is selected
    }
    
    if (locationListBox.SelectedIndex == -1)
    {
        // If no location selected
        MessageBox.Show("Select a Location, Please.");
        return;
    }

    var selectedWorkshop = workshopListBox.SelectedItem.ToString();
    
    var (numberOfDays, registrationFee) = selectedWorkshop switch
    {
        "Handling Stress" => (3, 1000),
        "Time Management" => (3, 800),
        "Supervision Skills" => (3, 1500),
        "Negotiation" => (5, 1300),
        "How to Interview" => (1, 500),
        _ => throw new ArgumentOutOfRangeException() // Invalid workshop selected
    };
    
    totalDaysLabel.Text = numberOfDays.ToString();
    feeOutputLabel.Text = registrationFee.ToString("c");

    var selectedLocation = locationListBox.SelectedItem.ToString();

    var lodgingFee = selectedLocation switch
    {
        "Austin" => 150,
        "Chicago" => 225,
        "Dallas" => 175,
        "Orlando" => 300,
        "Phoenix" => 175,
        "Raleigh" => 150,
        _ => throw new ArgumentOutOfRangeException() // Invalid location selected
    };

    // Calculate Lodging cost
    lodgingFee = numberOfDays * lodgingFee;
    totalLodgingLabel.Text = lodgingFee.ToString("c");

    // Calculate Total cost
    var totalCost = lodgingFee + registrationFee;
    totalCostLabel.Text = totalCost.ToString("c");
}

NightswyngOP•2w ago

ahh ok, so you put the messages at the top pretty much to establish and get out of the way. I really like the cleaned up version and what is the throw new mean?

Pobiega•2w ago

its how we do errors in C# so the _ => throw new ArgumentOutOfRangeException() line means "if its ANY OTHER value than the ones specified above, create a new error object and throw it up the call stack"

NightswyngOP•2w ago

oh ok can you be my professor? 😆 I will have to add that to my notes for the future

Pobiega•2w ago

Would if it paid decently 😛

NightswyngOP•2w ago

Its an online class so whats some extra income? lol I am gonna save your code to use as reference to clean up, but I was able to get the existing on working so I will submit that and set up with my professor one the version

Pobiega•2w ago

The trick to writing code like this is to break the problem down into smaller problems and handle them one at a time

NightswyngOP•2w ago

I was going over everything and couldnt figure it out until you pointed out there were no bindings then it clicked

Pobiega•2w ago

We can't do anything if the user didn't select values, so we check that first. Then we get the numbers for the workshop, then the location, and finally we do the math

NightswyngOP•2w ago

I have to remember to break it down, just get frazzled and lose sight

Pobiega•2w ago

You are far from alone in doing that. The code you pasted looks a lot like what most beginners code looks like

NightswyngOP•2w ago

its honestly what they show in the book

Pobiega•2w ago

Its more natural to think "if the user selected a valid value, calculate the registration fee..."

NightswyngOP•2w ago

Pobiega•2w ago

Rather than "if the user didn't select a valid value, stop them" Well the book is using ancient versions of C# so it doesn't have switch expressions :p

NightswyngOP•2w ago

lol can you do me a favor, and if you have a more updated modern suggestion on a book, I will gladly get it and read it to improve the outdated basics

Pobiega•2w ago

Sorry, I don't. The book I used to learn was outdated 20 years ago 😉 Gonna sleep, nn

NightswyngOP•2w ago

lol thats ok and totally fair, jsut thought i would ask. Thank you again for your help! much appreciated! sleep well

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