Help with GUI attempt #3 :P

Prime b

Vulpes, I am not sure if you read my last post in the old GUI thread, but I said I spent around 7 minutes to find that Form Designer lol...
Anyways I have done what you told me to do in last thread.
I found few more bugs, could you help me fix it ?
Like it will crash when I click previous and next button for like 3 or 4 times then they get disabled. My skip to first or skip to last works fine.
I also added option that date of birth calendar is not enabled in the view mode but only in edit mode, same with age box. Cause its the part of the requirements. But the age wont calculate automatically, logically when you select new age in the calendar it should update age box automatically right.
Its something about array, when my teacher crashed it he was saying something about how array is bad you should use some property that I have no idea about.

14 Replies

Know the answer? Post it — somebody with the same question will find it here.

Vulpes14y ago
Accepted answer
Yes, I noticed that but it's all there in Solution Explorer if you have a nose around :)

We are in fact using a List, namely 'ready'. We can't do anything about the RetreiveStudents() method in the PersistantData class returning an array as we're not alllowed to alter that but we can convert it to a List in the form class which is what we're doing.

The Age property will only recalculate when you 'get' it. The only place I can where this happens is in the DisplayStudent() method. If you're wanting to recalculate it automatically when editing the date of birth field, then you'll have to 'get' it again when focus leaves that textbox and redisplay it.

The reason for the bugs you mentioned is that there are still some changes you've overlooked from my list of changes in the last thread:

private void renameButton(object sender, EventArgs e)
{
//remove this student
DialogResult dr = MessageBox.Show("Are you sure you want to remove this student?", "Remove Student Confirmation", MessageBoxButtons.YesNo);
if (dr == DialogResult.No) return; // ** needs adding

// if (ready.Count == 0) return; // ** needs removing

data.RemoveStudent(ready[corn]);
ready.RemoveAt(corn);
//display the student before the one removed if there is one, otherwise display first student
if (corn > 0)
--corn;
else
corn = 0;

if (ready.Count > 0)
DisplayStudent(ready[corn]);
else
{
DisplayStudent(null);
viewStudEdit.Enabled = false;
viewStudRemove.Enabled = false;
}
if (corn == 0)
{
skipToFirstStudent.Enabled = false;
previousStudent.Enabled = false;
}
if (ready.Count < 2)
{
nextStudent.Enabled = false;
skipToLastStudent.Enabled = false;
}
}

private void previousButton(object sender, EventArgs e)
{
//shows the prev student
DisplayStudent(ready[--corn]);
if (corn == 0) // ** needs changing from corn == 1 to 0
{
skipToFirstStudent.Enabled = false;
previousStudent.Enabled = false;
}
if (corn == ready.Count - 2)
{
nextStudent.Enabled = true;
skipToLastStudent.Enabled = true;
}

}

private void skipBackButton(object sender, EventArgs e)
{
// shows the first student
// if (ready.Count == 0) return; // ** needs remmoving
if (corn == 0) return; // ** needs adding
corn = 0;
DisplayStudent(ready[corn]);
skipToFirstStudent.Enabled = false; // Disabled skip student when there's no students
previousStudent.Enabled = false; // Disables next student when there's no students
nextStudent.Enabled = true;
skipToLastStudent.Enabled = true;
}

Incidentally, 'renameButton' should of course be 'removeButton' if you fancy trying to refactor that.
Prime b14y ago
Yup, it all worked perfectly! Thank you VULPES.
Vulpes14y ago
OK, that's a bug on my part but I think I've fixed it by adding the highlighted code:

private void addStudentButton(object sender, EventArgs e)
{
viewStudRemove.Enabled = false;

if (addFirstNameTextBox.Text.Trim() == "" || addLastNameTextBox.Text.Trim() == "" || addStudentIdTextBox.Text.Trim() == "")
{
MessageBox.Show("All fields need to be completed", "Add student Error");
addFirstNameTextBox.Focus();
return;
}

int id = Convert.ToInt32(this.addStudentIdTextBox.Text);

foreach (Student s in students)
{
if (s.IdNumber == id)
{
MessageBox.Show("There's already a student with the same ID number", "Add Student Error");
addStudentIdTextBox.Focus();
return;
}
}
//adds student to storage
Student temp = new Student(this.addFirstNameTextBox.Text, this.addLastNameTextBox.Text, this.addDateOfBirth.Value, Convert.ToInt32(this.addStudentIdTextBox.Text));
data.AddStudent(temp);
students.Add(temp);
currentIndex = students.Count - 1;
// display the student just added
DisplayStudent(students[currentIndex]);
//clear Add fields for next add
nextStudent.Enabled = false;
skipToLastStudent.Enabled = false;

if (students.Count == 1)
{
viewStudEdit.Enabled = true;
viewStudRemove.Enabled = true;
}
else if (students.Count == 2)
{
skipToFirstStudent.Enabled = true;
previousStudent.Enabled = true;
}

addFirstNameTextBox.Text = "";
addLastNameTextBox.Text = "";
addStudentIdTextBox.Text = "";
addDateOfBirth.Value = new DateTime(1990, 1, 1);
viewStudRemove.Enabled = true;
}

The 4 navigation buttons will still be disabled when (after first deleting all the records) you add the first record as there's nowhere to go.

However, when the second record is added (inevitably at the end of the list), the 'skip to first' and 'previous' buttons will be enabled so the user can navigate to the first record.
Prime b14y ago
Vulpes, it works! thank you, there's last problem left. If you delete all the students and then add students the buttons are unavailable , only edit and remove available.
Here I uploaded updated version
Vulpes14y ago
Well, once the DatOfBirth property has been set, you have to 'get' the Age property to cause the necessary calculations to be performed.

So in your editButton method you need to add the highlighted lines (I'm using the old variable names for now):

if (dr == DialogResult.Yes)
{
ready[corn].FirstName = viewFirstNameTextBox.Text;
ready[corn].LastName = viewLastNameTextBox.Text;
ready[corn].DateOfBirth = viewDateOfBirth.Value;
viewAgeTextBox.Text = ready[corn].Age.ToString();
data.EditStudent(ready[corn]);
}

Notice that the age will only be recalculated once the Save button is pressed.
Prime b14y ago
Vulpes , so I want the age textbox display new age automatically . You said I have to 'get' it? What do you mean?
Vulpes14y ago
There's a lot of IT stuff that can become addictive - even posting on programming forums!

Anyway, addicted or not, I'm impressed by your obvious skills in the video game arena :)

The only Apple product I've ever bought is an IPad2 and - I must admit - it's a great piece of kit!

However, I agree that you certainly have to pay premium prices for their stuff - their laptops seem very overpriced compared to the Windows equivalents.

Also, I've never fancied programming for the Mac OS platform - even the thought of using Objective-C makes me feel queasy :(

If I were you, I'd stick to the Windows platform - Windows 7 laptops are pretty good and reasonably priced.
Prime b14y ago
I'll change that.
Well my passion for video games grew in to semi-addiction. I was pretty good at it too, was competing professionally(not sure if you know much about video games).
But i realized video games took over me and my time. So now I go to college do homework which is programming mostly and read books. It just sucks to waste 7 years on worthless video games, when I could have doing programming for 7 years instead, and I would have been a "professional" programmer. There's few things I learned from video games : practicing with best makes you the best in a lot shorter time than if you would have played with players that have same level of expertise as you are. I will catch up quick, I am just not sure enough if programming if that's what I want to do with my life.
I keep trying to sell my awesome video card so I can buy laptop but none is buying it... But return taxes are coming so I am going to use this money for new laptop.

You think apple is any good? I hear people talk about apple so much, but they are so overpriced just like anything else apple creates.
Vulpes14y ago
I thought 'ready' was a strange name for the List. I'd have called it 'students'.

Playing Video games has never had much appeal for me. Creating software has much more fascination for me than consuming it.
Prime b14y ago
I used corn as u advised and for snark I used studentAge. I didn't see any other confusing identifiers , do you remember any other confusing ones?
Also, do you play any video games?
Vulpes14y ago
Ah, I see :)

For 'corn' I'd use 'currentIndex' as it's the index in the List of the current student.

For 'snark' I'd use 'age' (as opposed to Age) because that's what it is.
Prime b14y ago
lol unfortunately I didn't make them up nor they mean anything in Russian. I have to change them to something meaningful
Vulpes14y ago
If you're asking me what those variable names are supposed to mean then I've no idea. I've never seen them used before in a programming context.

In fact, I though you'd made them up yourself and that they might mean something in Russian ;)
Prime b14y ago
Vulpes, whats corn and snark, in this form?