Develop Reference

Organizing inventory by alphabetical order

So I created a method to populate the inventory system I have created in Unity, however I can't seem to figure out a way to order them in alphabetical order. Each button is created as a child of the button holder panel which is a game object variable. This method is called whenever the player picks something up.
private void Populate_Inventory ( )
{
Button btn_CurrentItem;
int int_Count;
for ( int_Count = int_PreviousCount; int_Count < strList_Inventory.Count; int_Count++ )
{
btn_CurrentItem = Instantiate ( btn_Item, pnl_ButtonHolder.transform );
btn_CurrentItem.name = strList_Inventory [ int_Count ];
btn_CurrentItem.GetComponentInChildren<Text> ( ).text = strList_Inventory [ int_Count ];
btn_CurrentItem.gameObject.AddComponent<Inventory_Item> ( );
btn_CurrentItem.GetComponent<Inventory_Item> ( ).str_Name = cls_Pickup.str_PickupName;
btn_CurrentItem.GetComponent<Inventory_Item> ( ).str_Information = cls_Pickup.str_PickupInformation;
int_PreviousCount = int_Count;
}
int_PreviousCount++;
}
If anyone can help it would be very appreciated.
Jonathan Palmer

The primary issue with this approach is that you're adding single buttons at a time whenever you pick up an item, and those buttons are created as children of the pnl_ButtonHolder object, but your method has no knowledge of previous buttons that have been created.
Option 1 (Bad)
You can use the GetComponentsInChildren<Button>() method on the pnl_ButtonHolder object to get all of the button components that have been previously created once you've added a new button, and then sort your buttons according to their name.
This isn't ideal as GetComponentsInChildren<>() is an expensive method, and doesn't make use of the idea of an Inventory very well.
Option 2 (Good)
Create an Inventory class that manages your actual inventory, including sorting items. It might look something like this:
public class Inventory_Button : MonoBehaviour
{
public Button button = default;
public void Initialize(Intenvory_Item item)
{
button.name = item.name;
// Other work here.
}
}
public class Inventory : MonoBehaviour
{
public GameObject inventoryItemPrefab = default;
public Transform inventoryParent = default;
private List<Inventory_Item> _inventory = new List<Inventory_Item>();
private List<Inventory_Button> _inventoryButtons = new List<Inventory_Button>();
public void AddItem(Intenvory_Item item)
{
_inventory.Add(item);
Inventory_Button button = GameObject.Instantiate(inventoryItemPrefab, inventoryParent).GetComponent<Inventory_Button>();
button.Initialize(item);
_inventoryButtons.Add(button);
_inventoryButtons.Sort((x, y) => x.name.CompareTo(y.name));
}
public void RemoveItem(Inventory_Item item)
{
// Do work to remove the item.
}
}
This kind of setup is useful for several reasons:
Your inventory management is now handled by a single class rather than a collection of objects. This makes it easy to interact with.
It will make removing items much easier in the future. With your current implementation, it looks like you'd have a difficult time removing an item from the player's inventory.
It separates responsibility between an Inventory class, an Inventory_Item class, and an Inventory_Button class, each of which stands on its own and works together.
A few final notes:
I've left out some details in the two classes above. You should fill them in to fit the needs of your game.
You can be more efficient with sorting by using something like Insertion Sort. This solution will get the job done.
Using prefixes for naming your variables can be quite confusing to people trying to read your code. I recommend you check out a style guide. There's a great one here.

Is there a simple method to get coordinates of a particular item in a checkedlistbox?

I am making a simple class extending CheckedListBox that just adds a small textbox to the right of an item when it is checked. My issue is finding a good way to place the box at the correct location.
I had initially though I could use the Controls.Find() along with the ItemCheckEventArgs index to get the coordinates of the checkbox in question, and move to the right edge of the column from there. However, that did not work, and a brief look through the CheckedListBox class seemed to show that it does not actually contain any CheckBox controls, but merely draws images of them.
I then came up with the following method:
void CreateAmountBox(int index)
{
int itemsPerCol = Height/ItemHeight;
int x = GetColumn(index, itemsPerCol)*ColumnWidth - boxWidth;
int y = (index % itemsPerCol)*ItemHeight - offset;
System.Windows.Forms.TextBox NewAmountTextBox = new System.Windows.Forms.TextBox();
NewAmountTextBox.Location = new System.Drawing.Point(x, y);
NewAmountTextBox.Name = Items[index] + "Amount";
NewAmountTextBox.Size = new System.Drawing.Size(20, boxWidth);
Controls.Add(NewAmountTextBox);
}
where GetColumn(...) returns the column of the given index (from the CheckEventArgs). This works, but it feels like a hack and is not very readable.
Two other ideas I thought of:
1) I could just create all the TextBoxes at the start, and simply hide them until they are needed. Controls like these are all created dynamically throughout the rest of the program however, and I don't want these ones to be the odd exception. It also means that some more functionality needs to be added for cases when an item is added or removed.
2) I could use mouse position, which of course won't work if the input is via keyboard. I don't anticipate it ever being so, but best not to leave that possibility.
With some googling, the only other way I found of possibly doing this was using the ListBoxItem and TranslatePoint method, but I haven't gotten that to work, and I'm unsure as to whether it even can with a CheckedListBox instead of a ListBox.
So, is there a simple way of finding the x and y of the checked item that I don't know of? Or am I limited to simply extracting the x and y declarations above into a method and leaving it there?

You can just use the GetItemRectangle function to accomplish that:
void checkedListBox1_ItemCheck(object sender, ItemCheckEventArgs e) {
Rectangle r = checkedListBox1.GetItemRectangle(e.Index);
TextBox newAmountTextBox = new TextBox();
newAmountTextBox.Location = new Point(r.Left, r.Top);
//...
}

Entity framework object context saves new entities that were not added

I have been working with Entity Framework (VS2010 Framework 4.0) in my proyect. I had some trouble with using a different object context per form. What I did then, was to create a object context in the Main Menu Form (stays opened) and everytime I create and show one form, I pass that object context to this new form. Example:
public partial class frm_Menu : Base
{
public Sistema_financiero_Entities db = new Sistema_financiero_Entities();
private void cancelarCuotaToolStripMenuItem_Click(object sender, EventArgs e)
{
frm_Cancelacion_Cuota Form1 = new frm_Cancelacion_Cuota();
Form1.db = db;
Form1.Show();
}
}
Ok, that solution worked fine until now because I needed to use and pass objects throw the differents forms sometimes, and if the objects contexts were different, I got an error.
Now, I have detected a huge issue using it this way. I have a form, where I can pay for the different installments of a loan. I´ll attach an image so then you can see what I´m talking about.
There, you select the different installments you want to pay for. Then, you introduce the value you will finally pay in "Total cobrado". Here is the important thing: When the checkbox image is checked (the blue one - already checked in the image), I create a "payment" entity per installment. Every "payment" object is stored in a list. If I uncheck it, I can change the value and the same thing is done. Obviously, I´m clearing the list before doing a list.Clear();. Then, one the checkbox checked, I can press "Aceptar" (accept). There I add to the database every "payment"(PAGO) in the list. After that, I save all changes.
foreach (Pago p in Lista_nuevos_pagos)
{
db.AddToPago(p);
}
try
{
db.SaveChanges();
this.Close();
}
My problem, is that it´s not only adding those "payments" in the list but the other "payments" entities that were in the list before clearing it. I reach the conclusion that when I clear the list, the objects remains in the object context. I thought that if the entity is not in the database, I have to Add it to the entity in the object context as I did with pago (db.AddToPago(p);).
I wanted to ask you guys how can I solve this issues. I solved it now doing this:
private void cancelarCuotaToolStripMenuItem_Click(object sender, EventArgs e)
{
Sistema_financiero_Entities db = new Sistema_financiero_Entities();
frm_Cancelacion_Cuota Form1 = new frm_Cancelacion_Cuota();
Form1.db = db;
Form1.Show();
}
Instead of creating just one global db for all forms, I create one in the Main Menu for every form. Then, in that form closed event, I dispose that object context.
Then, when i check the checkbox image, before creating the "payments", I delete every "Pago" entity from the object context:
foreach (Pago p in Lista_nuevos_pagos)
{
db.DeleteObject(p);
}
Lista_nuevos_pagos.Clear();
Doing this works correctly, but I´m still having trouble with some other created entities (Installments) that are not deleted when I clear a list. I think I´m doing it wrongly, thats why I need some direction to use EF correctly. I really need to get this done really soon, I don´t have too much time to read EF tutorials.
Just in case, this is how I create every "Pago" (payment)
Pago p = new Pago();
p.desc_aumento_intereses = nudwb1.Value;
p.desc_aumento_punitorios = nudwb2.Value;
p.desc_aumento_gastos = nudwb3.Value;
p.desc_aumento_comision = nudwb4.Value;
p.cotizacion = ntxt_Cotizacion.Value;
p.fecha_hora = fecha_hora;
Cuota c = new Cuota();
string name = tbx.Name.Substring(tbx.Name.IndexOf("-") + 1);
int nro_cuota = Convert.ToInt32(name);
c = Lista_cuotas_cobrar.Where(x => x.num_cuota == nro_cuota).First();
p.Cuota.Add(c);
Thank you for reading, I know this is a lot of info. Hope some guide soon..

I guess that you have references to those object in your Lista_nuevos_pagos list. This is why they will be duplicated.

How to hold a table of data for user edition (before saving in the the database)?

I've been using this programming style, that I've seen in an example and just started using it, because it does the job... I would like to know other programmers' opinion about it...
So the situation is when you have a GridView, or a control based on it like the RadGrid, and you want to keep track of a data table while you are adding, editing, reordering and deleting rows.
Using the session to hold the data table (or list of data) may not be the best solution, because the user may open two identical web pages… Using the ViewState to hold the data may be and option... I have been using an approach like the following:
public partial class DefaultPage : System.Web.UI.Page
{
protected DataLine DefaultDataLine()
{
DataLine dl = new DataLine();
dl = new DataLine();
dl.Number = 0;
dl.Title = "";
dl.Text = "";
return dl;
}
protected class DataLine
{
public int Number { get; set; }
public string Title { get; set; }
public string Text { get; set; }
}
protected static List<DataLine> tempLines;
protected void Page_Load(object sender, EventArgs e)
{
if (!this.IsPostBack)
{
tempLines = RadGridBindStartUpData();
}
}
protected void RadGrid1_NeedDataSource(object source, Telerik.Web.UI.GridNeedDataSourceEventArgs e)
{
RadGrid1.DataSource = tempLines;
}
protected void RadGrid1_InsertCommand(object source, Telerik.Web.UI.GridCommandEventArgs e)
{
GridEditableItem editedItem = e.Item as GridEditableItem;
List<DataLine> table = tempLines;
DataLine newRow = new DataLine ();
RadTextBox rtb;
rtb = (RadTextBox)editedItem.FindControl("RadTextBoxTitle");
newRow.Title = rtb.Text;
rtb = (RadTextBox)editedItem.FindControl("RadTextBoxDescription");
newRow.Description = rtb.Text;
RadNumericTextBox number = (RadNumericTextBox)editedItem.FindControl("RadNumericTextBoxNumber");
newRow.Number = number.Value.HasValue ? Convert.ToInt32(number.Value.Value) : 0;
table.Add(newRow);
}
// ...
So using a static List variable, of a custom object (class), declared in the code-behind of the Aspx page, and updating it whenever the data is edited.
What are your thoughts about this approach? Is it okay? How do you hold your table-format data for edition (prior to saving it in the database)?

Not exactly sure what you're going for, but using a static variable is probably not what you want to do. Static properties are shared across all user/threads, so all concurrent users would be editing the same data.
If you are just looking to persist a small data set across post-backs to the same page, use the ViewState instead. Just be mindful of potential performance issues if you plan on cramming lots of data into it.

It depends on what you're wanting to achieve
Viewstate will keep the data on that page - it won't be available on any other pages (or tabs, or windows)
Session will keep the data on the server, this means it will be available for any page the user is looking at (on your site) and it will keep it until the session times out.
Theres a lot of advtanges/disadvantages to either method, therefore you need to research your situation, here is a start.

You mentioned storing in the session, and how this could cause issues if the user opens up multiple copies of the page, etc...
We had a similar issue so I made a property in code behind on the page and on first page load (if not postback blah blah) I generate a new guid. Then I use the guid value as my session key and I know it'll be unique per page.
You could make a spify property like this...
Public ReadOnly Property SessionDataKey() As String
Get
If ViewState("SessionDataKey") Is Nothing Then
ViewState("SessionDataKey") = Guid.NewGuid()
End If
Return ViewState("SessionDataKey").ToString()
End Get
End Property
But in short, I just use the session.

Thank you very much for your replies! With your help, and some research, I see that both approaches, storing in session or using the static variable are indeed wrong, at least for the purpose I was using them... All your answers were helpful, and although I can only mark one as correct, I would like to leave my appreciation.
Well, for anyone stumbling across the same problem, here’s what I’ve implemented in my pages:
public partial class ScriptAdd : System.Web.UI.Page
{
private List<MyItem> tempMyItems
{
get
{
//if (ViewState["tempMyItemsList"] == null)
// ViewState["tempMyItemsList"] = new List<MyItem>();
return (List<MyItem>)ViewState["tempMyItemsList"];
}
set
{
ViewState.Add("tempMyItemsList", value);
}
}
protected void Page_Load(object sender, EventArgs e)
{
// ...
}
}
And then use it whenever I want to add / insert / update lines to my temporary list:
List<MyItem> table = tempMyItems;
table.RemoveAt(idx);
MyItem newRow = new MyItem ();
// ...
table.Insert(idx, newRow);
Finally, if intended, I store all the items in the database.

Correct way to implement web part personalisation for listboxes

Trying to work out this whole web part personalisation, and trying to implement it for a list box.
Well the end result will be two list boxes, with interchangeable values (ie, a value will only exist in one of the listboxes)
But I can't maintain the datasource for it. So maybe I'm going about it wrong?
This is what I have for a test H2 tag on the page
[Personalizable(PersonalizationScope.User)]
public string LabelText {
get { return h2Test.InnerText; }
set { h2Test.InnerText = value; }
}
And it works fine, if I have a textbox and use it to change the value of LabelText, then when I close the browser it automagically persists the change.
So I thought, ok, then maybe the same will work with a list box
[Personalizable(PersonalizationScope.User)]
public DomainList Domains {
get { return (DomainList)lstBxDomains.DataSource; }
set {
lstBxDomains.DataSource = value;
lstBxDomains.DataBind();
}
}
Where DomainList is just a class which extends List, and Domain is just a three field class, int, string, string.
But it doesn't, so is this too complicated for the webpart personalisation automagican, or have i just implement it wrongly (Which is more than likely)
This is my event handler to remove the items from the list:
protected void btnRemDomain_Click(object sender, EventArgs e) {
if (IsPostBack && lstBxDomains.SelectedIndex > -1) {
for (int i = 0; i < lstBxDomains.Items.Count; i++) {
if (lstBxDomains.Items[i].Selected) {
Domains.Remove(Domains.Find(d => d.ID.ToString() == lstBxDomains.Items[i].Value));
}
}
Domains = Domains;
}
}
The Domains=Domains; line is in there to see if explicitly setting the value made a difference (as Removing doesn't acutally reset the value of the field), but it doesn't. I've also tried creating a new local DomainList setting it to the global one, and then doing the remove/find on it, and then setting the local one to the global. But not working either.

I have managed to resolve this by using WebPart.SetPersonalizationDirty(this); in the set accessor of Domains, but would someone mind confirming if this is an appropriate way to do it?