C# – How to get Selected items in WPF CheckBox ListBox

ccheckboxlistboxwpf

Am Using the checkbox in listbox items, how to get the selected checkboxes from the list

<ListBox ItemsSource="{Binding NameList}"  HorizontalAlignment="Left" Margin="16,68,0,12" Name="listBox1" Width="156" IsEnabled="True" SelectionMode="Multiple" Focusable="True" IsHitTestVisible="True" IsTextSearchEnabled="False" FontSize="12" Padding="5" SelectionChanged="listBox1_SelectionChanged">
            <ListBox.ItemTemplate>
                <DataTemplate> 
                        <StackPanel Orientation="Horizontal">                      
                               <CheckBox Content="{Binding Path=CNames}" />
                        </StackPanel>
                </DataTemplate>
            </ListBox.ItemTemplate>
        </ListBox>

I tried to loop thru the selected items in the listboxitems, but it throws exception in listboxitem

 private void btnSelected(object sender, RoutedEventArgs e)
    {
        foreach (ListBoxItem item in listBox1.Items)
        {
            if (item.ToString() == "true")
            {
                MessageBox.Show(item.Content.ToString());
            }
        }
    }

Best Answer

You could move the data context for each of these items away from the UI and create an ObservableCollection of objects

public ObservableCollection<CheckedItem> List { get;set;}

public class CheckedItem : INotifyPropertyChanged
{
  private bool selected;
  private string description;

  public bool Selected 
  { 
     get { return selected; }
     set 
     {
        selected = value;
        OnPropertyChanged("Selected");
     }
  }

  public string Description 
  { 
     get { return description; }
     set
     {
         description = value;
         OnPropertyChanged("Description");
     }
   }

  /* INotifyPropertyChanged implementation */
}

Then in your ListBox ItemTemplate

<ItemTemplate>
  <DataTemplate>
    <CheckBox IsChecked="{Binding Path=Selected}" 
              Content={Binding Path=Description}" />
  </DataTemplate>
</ItemTemplate>

Your selected items are now available in the ObservableCollection rather than looping through UI elements

Related Solutions

C# – How to get a consistent byte representation of strings in C# without manually specifying an encoding

Contrary to the answers here, you DON'T need to worry about encoding if the bytes don't need to be interpreted!

Like you mentioned, your goal is, simply, to "get what bytes the string has been stored in".
(And, of course, to be able to re-construct the string from the bytes.)

For those goals, I honestly do not understand why people keep telling you that you need the encodings. You certainly do NOT need to worry about encodings for this.

Just do this instead:

static byte[] GetBytes(string str)
{
    byte[] bytes = new byte[str.Length * sizeof(char)];
    System.Buffer.BlockCopy(str.ToCharArray(), 0, bytes, 0, bytes.Length);
    return bytes;
}

// Do NOT use on arbitrary bytes; only use on GetBytes's output on the SAME system
static string GetString(byte[] bytes)
{
    char[] chars = new char[bytes.Length / sizeof(char)];
    System.Buffer.BlockCopy(bytes, 0, chars, 0, bytes.Length);
    return new string(chars);
}

As long as your program (or other programs) don't try to interpret the bytes somehow, which you obviously didn't mention you intend to do, then there is nothing wrong with this approach! Worrying about encodings just makes your life more complicated for no real reason.

Additional benefit to this approach: It doesn't matter if the string contains invalid characters, because you can still get the data and reconstruct the original string anyway!

It will be encoded and decoded just the same, because you are just looking at the bytes.

If you used a specific encoding, though, it would've given you trouble with encoding/decoding invalid characters.

Javascript – How to check whether a checkbox is checked in jQuery

How do I successfully query the checked property?

The checked property of a checkbox DOM element will give you the checked state of the element.

Given your existing code, you could therefore do this:

if(document.getElementById('isAgeSelected').checked) {
    $("#txtAge").show();
} else {
    $("#txtAge").hide();
}

However, there's a much prettier way to do this, using toggle:

$('#isAgeSelected').click(function() {
    $("#txtAge").toggle(this.checked);
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<input type="checkbox" id="isAgeSelected"/>
<div id="txtAge" style="display:none">Age is something</div>

Best Answer

Related Solutions

C# – How to get a consistent byte representation of strings in C# without manually specifying an encoding

Javascript – How to check whether a checkbox is checked in jQuery

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