Question

I actually have two questions:

(1) Is it possible to put another image on top of an ImageButton that already has an ImageUrl set (without changing the ImageUrl – literally just add the second image ‘on top’)? Even by using CSS?

(2) I have a dynamically set number of ImageButtons contained within a ListView. When a user clicks on an ImageButton, I change the .CssClass property of the one clicked in order to ‘highlight’ it. My question is this: whenever an ImageButton is click, I need to not only highlight it, but make sure I unhighlight all the others. However, I’m having trouble getting the others. I get the clicked ImageButton using

((ImageButton)sender).CssClass = "SelectedImageButton";

in the event handler. However, how do I get all the others so I can set their style ‘back’ to the unhighlighted style?

Thanks in advance for any help!

UPDATE: ANSWERED!
I’ve solved the issue mentioned in (2) using the following algorithm. Note, I’ve marked @OFConsulting’s answer below as the correct answer because without his algorithm, I would have never gotten the following algorithm (which came from tweaking his algorithm slightly). Thanks @OFConsulting!

// Cast the sender to an ImageButton to have the clicked ImageButton
ImageButton clickedImageButton = sender as ImageButton;

// The ListView has ListViewDataItems and the ImageButtons are in 
// THOSE children controls, thus match on the ImageButtons' Parents' IDs
Control parentControl = clickedImageButton.Parent;
List<ListViewDataItem> allOtherImageButtons = MyListView.Controls.OfType<ListViewDataItem().AsQueryable().Where(i => i.ID != clickedImageButton.Parent.ID).ToList();

// Highlight
clickedImageButton.CssClass = "HighlightedStyle";

// Unhighlight
foreach (ListViewDataItem button in allOtherImageButtons)
{
    // The ImageButton is always the 2nd child control of the ListViewDataItem
    ImageButton childImageButton = (ImageButton)button.Controls[1];
    childImageButton.CssClass = "NoHighlightedStyle";
}

Answer 1

For Part (1) of that question, setting the background image within your css class might do the trick, but you never really explained why you just couldn’t change the ImageUrl. You can always throw everything on an update panel if you need it to be dynamic without the hassle of a bunch of script.

Part (2) seems pretty straight forward. Just use a little bit of linq against the relevant control collection within your page.

protected void ImageButton5_Click(object sender, ImageClickEventArgs e)
{
    ImageButton clickImageButton = sender as ImageButton;

    // This example assumes all the image buttons have the same parent.
    // Tweak as needed depending on the layout of your page
    Control parentControl = clickImageButton.Parent;
    List<ImageButton> allOtherImageButtons = parentControl.Controls.OfType<ImageButton>().AsQueryable().Where(i => i.ID != clickImageButton.ID).ToList();

    // Highlight
    clickImageButton.CssClass = "WhateverHighlights";

    // Unhighlight
    foreach (ImageButton button in allOtherImageButtons)
    {
        button.CssClass = "WhateverClears";
    }
}

Edit: One more thing. Make sure any controls you are adding dynamically get added before Page_Load (I.E. during Init). There are some viewstate issues associated with adding control too late.