i am trying to create a simple image button rollover.. i have
searched this forum and found a number of solutions but none seem to
work. i am just trying to get the onmouseover to swap the image then
restore when rolled out on a web page in vb.net. please can someone
help?
I did it on the server side, while I was setting up the page. Most of
my pages have an OK button and a Cancel button. For consistency's
sake, the images are all named the same. That is, the standard buttons
end in ".jpg" and the hover style ends in "_hover.jpg".
We use ImageButton controls to represent buttons so that we can
respond to click events server-side. When I'm designing the form, I
always only set the ImageUrl property, and I always only set it to the
*unhovered* image.
I wrote a method in the page's base class called SetButtonImages, that
looks something like this:
Protected Sub SetButtonImages(ByVal button As ImageButton)
Dim imageUrl As String
imageUrl = button.imageUrl
' Set the image that appears when the user moves the mouse off
' of the button.
image.Attributes.Add("onmouseout", "src=""" & imageUrl & """")
' Remove the .jpg extension, and add the "_hover.jpg" extension
imageUrl = imageUrl.SubString(0, imageUrl.Length - 4)
imageUrl &= "_hover.jpg"
' Set the image that appears when the user hovers the mouse
' over the image button.
button.Attributes.Add("onmouseover", "src=""" & imageUrl & """")
End Sub
(WARNING: I'm recalling this from memory, since the boss just tweaked
our firewall, and I can't peak at the source code to refresh my
memory, so I'm sorry if there are bugs.)
The method is invoked in the derived pages, like this:
Protected Sub PageLoad(ByVal sender As Object, ByVal e As EventArgs)
Handles Page.Load
...
SetButtonImages(btnOk)
SetButtonImages(btnCancel)
End Sub
This implementation saved me a lot of time, but it's based on a base
class for your pages. If you're not using a base class, you can simply
put the SetButtonImages function in a sepraate class, or even in a
module and invoke it from there (so that you don't have to repeat it
in every page). Once you have that method working the way you want it
to, it becomes highly reusable. You can change the file extension to
match whatever image types or file names you're using.
The caveat, of course, is that you have a consistent image naming
scheme. You can, of course, change the arguments to the method to pass
in the names of the images. That simplifies the entire task, and is
likely far more reliable if your file names aren't consistent. (A lack
of consistency doesn't mean anything--it's a frequent phenomenon, and
just indicates that the images likely came from disparate sources.)
I hope this helps!
Mike
