[Mono-list] How to maintain values in a HtmlSelect when modifying the content with javascript ?

[John BouAntoun]

I suggest looking at the samples in the xsp project for drop down list.

If you are wanting to work with any html form controls on both the =
server side (C#) and the client side (javascript) then you really should =
look at using controls in the System.Web.UI.WebControls namespace and =
not the System.Web.UI.HtmlControls.

Controls in the System.Web.UI.WebControls namespace still render to the =
page as normal html form controls,
so you should be able to access them using javascript on the client.

A good tip to keep in mind when using javascript on =
System.Web.UI.WebControls, is that each control has a ClientID property =
that is the string value of the client side control's id.

So if you had a drowdown list called listbox1, when writing javascript =
to the page you would do something like this:

private void PageLoad()
{
	if(!IsPostback)
	{
		// build the client script to display the client side select item from =
the listbox1 object
		clientscript =3D "<script>alert('this is the client side list box =
control: ' + ";
		clientscript +=3D "document.getElementById('"
		clientscript +=3D listbox1.ClientID
		clientscript +=3D @"'));</script>";

		// register this script to run once the program has started
		Page.RegisterStartupScript("listbox1", clientscript);
	=09
	}
}

Hopefully that example shows you how interactions between client and =
server side work.

JBA

-----Original Message-----
From: Tiago Lima [mailto:tiago.lima@vianw.pt]
Sent: Friday, 12 December 2003 10:15 AM
To: John BouAntoun; mono-devel mailing list; mono-list mailing list
Subject: Re: [Mono-list] How to maintain values in a HtmlSelect when
modifying the content with javascript ?


Thanks, I will see that..

But in that case, how do I handle that in javascript, just like a =
<select>?

	Tiago Lima

On Thursday 11 December 2003 23:06, John BouAntoun wrote:
> Tiago,
>
> If you want to use the equivalent of a Html Select element, that is =
able to
> have it's values handle in C# on the server (i.e. on page load and =
after a
> postback etc) then why not simply use the
> System.Web.UI.WebControls.DropdownList item?
>
> You can bind the dropdown list option elements to records in a =
dataview or
> dataset and you can also get / set the selected index.
>
> I'm pretty sure that's what you are looking for.
>
> JBA
>
>
>
> -----Original Message-----
> From: Tiago Lima [mailto:tiago.lima@vianw.pt]
> Sent: Friday, 12 December 2003 10:00 AM
> To: mono-devel mailing list; mono-list mailing list
> Subject: [Mono-list] How to maintain values in a HtmlSelect when
> modifying the content with javascript ?
>
>
> Hi,
>
> I've a question regarding whether an HtmlSelect maintains the =
"options"
> inside it when these options get modified in javascript. I dont know =
how
> Microsoft .NET handles this...
>
> I have two HtmlSelects, one of them starts empty and the other one =
have all
> the elements... The user moves around the elements from one to another =
and
> then posts the result... I want to know the elements in the first
> HtmlSelect... How do I do this?
>
> If I select one of the elements in the first HtmlSelect then I get an
> error:
>
> System.IndexOutOfRangeException: Array index is out of range
> in [0x00074] (at /home/duncan/Mono/mcs/class/System.Web/
> System.Web.UI.HtmlControls/HtmlSelect.cs:209)
> =
System.Web.UI.HtmlControls.HtmlSelect:System.Web.UI.IPostBackDataHandler.=
Lo
>adPostData (string,System.Collections.Specialized.NameValueCollection)
> i
> ...
>
> this is because the HtmlSelect has no elements in the beggining !
>
> Is the System.Web.UI.WebControls.ListBox controls doing this?
>
> Thanks in advance,
> 	Tiago Lima
>
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