Question

jQuery can select the Child of something, or Parent, or next tag. Does C# have something similar to this behavior. For example, I have a horizontal StackPanel that has a Label, a TextBox, and a Button.

Can I target the Label to change color if the TextBox is currently selected without using if else statements referring to the name of the Label? Some function like “this label” in this StackPanel that this TextBox is in.

Example: Whenever a text box is selected, the label next to it changes to yellow background.

I’m not sure how to write this in C# so I will try to explain with regular text.

if (this) textbox is selected
    get the label next to it
    change the label background to a color

else
    remove the color if it is not selected

The Method() will trigger based on the currently selected TextBox.

A function like this can have the same code but be able to target different Labels once the focus changes to a different TextBox. Is this possible?

Answer 1

Yes, You can; you should handle events. for example in this case you handle ‘TextBox.GotFocus` event.

void tb_GotFocus(object sender, GotFocusEventArgs e)
{
     // here you can get the StackPanel as the parent of the textBox and 
     // search for the Lable
     TextBox tb=(TextBox)sender;
     StackPanel sp=tb.Parent as StackPanel;

     // and ...
}

If you want to omplete this example let me know.

Edit
This is a working Example:

Use this Window to show the results:

Window win = new Window();
        StackPanel stack = new StackPanel { Orientation = Orientation.Vertical };
        stack.Children.Add(new CustomControl());
        stack.Children.Add(new CustomControl());
        stack.Children.Add(new CustomControl());
        stack.Children.Add(new CustomControl());
        win.Content = stack;
win.ShowDialog();

Here, is the CustomControl class:

public class CustomControl : Border
{
    Label theLabel = new Label {Content="LableText" };
    TextBox theTextbox = new TextBox {MinWidth=100 };

    public CustomControl()
    {
        StackPanel sp = new StackPanel { Orientation=Orientation.Horizontal};
        this.Child = sp;
        sp.Children.Add(theLabel);
        sp.Children.Add(theTextbox);

        theTextbox.GotFocus += new RoutedEventHandler(tb_GotFocus);
        theTextbox.LostFocus += new RoutedEventHandler(tb_LostFocus);
    }


    void tb_GotFocus(object sender, RoutedEventArgs e)
    {
        theLabel.Background = Brushes.Yellow;
    }
    void tb_LostFocus(object sender, RoutedEventArgs e)
    {
        theLabel.Background = Brushes.Transparent;
    }
}