How to arm selected checkbox in an array in c#

Question

Hello, I’m new in development in c# and have in my form an option for fruit selection

Grape[] Pera[x] Apple[] Banana[x]

How I could store in an array only the selected checkbox?

Answer 1

In this case you can use a Checkboxlist and navigate through the options(Items) by checking which one you are selecting. In the example I put 2 of the 4 marked options and used LINQ to go through all and add in an array only the selected ones:

HTML

<form id="form1" runat="server">
    <div>
        <asp:CheckBoxList ID="ckbFrutas" runat="server">
            <asp:ListItem Selected="True" Value="1">Uva</asp:ListItem>
            <asp:ListItem Value="2">Pêra</asp:ListItem>
            <asp:ListItem Selected="True" Value="3">Maça</asp:ListItem>
            <asp:ListItem Value="4">Banana</asp:ListItem>
        </asp:CheckBoxList>
    </div>
</form>

---

C#

protected void Page_Load(object sender, EventArgs e)
{
    //LINQ
    ListItem[] selected2 = ckbFrutas.Items.Cast<ListItem>().Where(li => li.Selected).ToArray();
}

As I do not know which event is doing this put in Page_load even just to demonstrate. If you prefer to use a normal foreach instead of LINQ and if the Checkboxlist options are being filled dynamically (the amount may vary), use a list(List) structure instead of an array so you don’t have to resize all the time.

To capture the value take the "Value":

//LINQ
List<string> selected2 = ckbFrutas.Items.Cast<ListItem>().Where(li => li.Selected).Select(li => li.Value).ToList();

Or:

foreach (ListItem item in ckbFrutas.Items)
{
    if (item.Selected)
    {
       string selectedValue = item.Value;
    }
}

See that in the case I showed it will return the values "1" and "3"