Dynamically setting a MasterPage's <body> tag style

Mark Rae · Jul 10, 2006

Hi,

It's easy enough for a child page to manipulate its MasterPage's header
simply by modifying the MasterPage thus:

<header runat="server">
....
....
</header>

Then, in code, we can do stuff like Header.Title = "Welcome";

However, is it possible to do the same for the MasterPage's <body > tag?

Specifically, I'm looking for a way to get a child page to create the
following HTML on some pages but not on others:

<body style="BACKGROUND-POSITION: center bottom; BACKGROUND-ATTACHMENT:
fixed; BACKGROUND-IMAGE: url(images/skylinelogo.gif); BACKGROUND-REPEAT:
no-repeat">

I don't really want to have a second MasterPage just for this, because this
background image is the only change to the basic layout of this site - only
the contents of the child pages changes, obviously... However, I do
appreciate that that would be a very simple and quick workaround...

Any assistance gratefully received.

Mark

Guest · Jul 10, 2006

Mark,
Wouldn't you be better off setting the body Style css in a Stylesheet
instead of inline on the tag, and then just arranging to load the correct
stylexx.css dynamically into the page?
Peter

Mark Rae · Jul 10, 2006

Peter,

Wouldn't you be better off setting the body Style css in a Stylesheet
instead of inline on the tag, and then just arranging to load the correct
stylexx.css dynamically into the page?

Yes, I could do that.

So, is there no easy way of manipulating a MasterPage's <body /> tag in the
same way is its <head /> tag...?

Mark

=?ISO-8859-1?Q?G=F6ran_Andersson?= · Jul 11, 2006

Mark said:
Peter,

Yes, I could do that.

So, is there no easy way of manipulating a MasterPage's <body /> tag in the
same way is its <head /> tag...?

Mark

Aren't you missing the point here? If you set the style using a css file
you don't have to do any manipulation of the body tag at all.

Mark Rae · Jul 11, 2006

Aren't you missing the point here? If you set the style using a css file
you don't have to do any manipulation of the body tag at all.

Dynamically...

Sometimes the child page needs the background, sometimes it doesn't...

=?ISO-8859-1?Q?G=F6ran_Andersson?= · Jul 11, 2006

Mark said:
Dynamically...

Sometimes the child page needs the background, sometimes it doesn't...

Yes, dynamically. You can for instance use themes.

Mark Rae · Jul 11, 2006

Yes, dynamically. You can for instance use themes.

Or two MasterPages, even...

Thanks anyway.

John Timney \(MVP\) · Jul 11, 2006

example of dynamically choosing CSS as Peter suggested......

http://www.codeproject.com/aspnet/setcssfilelink.asp

Regards

John Timney (MVP)

JT · Jul 11, 2006

Sometimes people just want their questions answered. Seems reasonable,
especially since I'm interested in the same answer.

John Timney \(MVP\) · Jul 11, 2006

The answer is probably quite sparse as people are following the methods
suggested in the thread. You should not set the body tag, you should change
the master page dynamically. If you wish to set only a CSS element (like
body styling) then switch the CSS to an alternate. You should avoid
embedding CSS against single elements as it creates less seperation between
logic and UI.

If you want to work just with the body tag then you could allocate a runat
server attribute to your body tag In the master page.
<body runat="server" id="masterBody">

in the Page_Load event of the container add something like:
HtmlGenericControl body = (HtmlGenericControl)
Page.Master.FindControl("masterBody");
body.Attributes.Add("style", "BACKGROUND-POSITION: center bottom;");

You would only need to add this to load events in containers that required
it. I've never tried it mind you, it might not work!!!

Regards

John Timney (MVP)

Mark Rae · Jul 12, 2006

John,

If you want to work just with the body tag then you could allocate a runat
server attribute to your body tag In the master page.
<body runat="server" id="masterBody">

in the Page_Load event of the container add something like:
HtmlGenericControl body = (HtmlGenericControl)
Page.Master.FindControl("masterBody");
body.Attributes.Add("style", "BACKGROUND-POSITION: center bottom;");

You would only need to add this to load events in containers that required
it. I've never tried it mind you, it might not work!!!

Thanks for this! Firstly, I can confirm that it does work...

However, curiously, the line which instantiates the HtmlGenericControl
object generates an error which is not caught by the standard try..catch
handler. By which I mean that stepping through the code below I can see that
an error is raised, but this doesn't jump into the error handler, and
continues through the code.

The MasterPage body tag is as follows:

<body id="objBody" runat="server">

The Page_Load of the child page is as follows:

protected void Page_Load(object sender, EventArgs e)
{
try
{
HtmlGenericControl objBody =
(HtmlGenericControl)Master.FindControl("objBody");
objBody.Attributes.Add("style", "background-image:
url(../images/skylinelogo.gif);");
}
catch (Exception ex)
{
CApplication.GlobalExceptionHandler(ex);
}
}

The error is:

{InnerText =
'((System.Web.UI.HtmlControls.HtmlContainerControl)(objBody)).InnerText'
threw an exception of type 'System.Web.HttpException'}
base {System.Web.UI.HtmlControls.HtmlContainerControl}: {InnerText =
'((System.Web.UI.HtmlControls.HtmlContainerControl)(((System.Web.UI.HtmlControls.HtmlGenericControl)(objBody)))).InnerText'
threw an exception of type 'System.Web.HttpException'}
TagName: "body"

Now, can anyone please tell me:

1) What the error means?

2) Why it isn't caught by the try...catch handler?

3) Is it safe to ignore it, since the code proceeds past it and does what
it's supposed to do?

Any assistance gratefully received.

Mark

John Timney \(MVP\) · Jul 12, 2006

To hazard a guess (I dont have a dev environment handy) could it be because
you have called your generic control and your body server control the same
names objBody, and your telling findcontrol to look for itself

Regards

John Timney (MVP)

Mark Rae · Jul 12, 2006

To hazard a guess (I dont have a dev environment handy) could it be
because you have called your generic control and your body server control
the same names objBody, and your telling findcontrol to look for itself

Nope - I already thought of that and changed the variable name, but that
made no difference.

Incidentally, doing the whole thing in one long line doesn't generate the
error... e.g.

This generates the error, on the first line:

HtmlGenericControl HTMLBody =
(HtmlGenericControl)Master.FindControl("objBody");
HTMLBody .Attributes.Add("style", "background-image:
url(images/skylinelogo.gif);");

But this doesn't:

((HtmlGenericControl)Master.FindControl("objBody")).Attributes.Add("style",
"background-image: url(images/skylinelogo.gif);");

Both work perfectly...

This has really piqued my curiosity now! Can anyone shed any light on what's
happening here...?

I'm about to get in trouble with the HTML <body></body> tags	10	Aug 12, 2023
Style Tag Problem	1	May 16, 2020
Centering a button using flexbox	2	Feb 5, 2023
I just want a background image	5	Jan 3, 2020
HTML Anchor tag not working	2	Dec 15, 2020
I need help fixing my website	2	Oct 15, 2023
How can I get my menu inside of a menu to function properly?	1	Jan 19, 2023
Background image not showing up on html page	3	Sep 23, 2023

Dynamically setting a MasterPage's <body> tag style

Mark Rae

Guest

Mark Rae

=?ISO-8859-1?Q?G=F6ran_Andersson?=

Mark Rae

=?ISO-8859-1?Q?G=F6ran_Andersson?=

Mark Rae

John Timney \(MVP\)

JT

John Timney \(MVP\)

Mark Rae

John Timney \(MVP\)

Mark Rae

Ask a Question

Similar Threads

Members online

Forum statistics

Latest Threads