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I have a custom control and I want to dynamically insert a link to a stylesheet.
Might not be the best solution of the year but it needs to be done. Any idea how to do it?
Everytime I try, Page.Header is null.
890
If you want to change the CSS styles dynamically you'll have to attach this portion of code to some event. For example, if you want to change the styles of your element when clicking on a button, then you have to first listen to the click event and attach a function containing the previous code.
This is a collection of methods which give you the ability to query the stylesheets collection in a document, add and remove rules, and dynamically create new sheets.
ASP.NET Web pages function as HTML pages at run time. You can therefore use cascading style sheets (CSS) to set the appearance of any elements on the page other than Web server controls.
In Solution Explorer, right-click the name of the Web site, and then click Add New Item. In the list of templates, select Style Sheet. In the Name box, type Layout. css, and then click Add.
To avoid the problem of multiple stylesheets when adding the control 10 times to the page, change the above code slightly:
string styleSheet = "stylesheetName.css";
if (this.Page.Header.FindControl(styleSheet) == null)
{
HtmlLink cssLink = new HtmlLink();
cssLink.ID = styleSheet;
cssLink.Href = "~/styles/" + styleSheet;
cssLink.Attributes.Add("rel", "stylesheet");
cssLink.Attributes.Add("type", "text/css");
this.Page.Header.Controls.Add(cssLink);
}
By giving the control an ID you can check if it already exists, and so ensure that you only add it the once.
74
Here's how you would normally add a CSS programatically:
protected void Page_Init(object sender, EventArgs e)
{
var link = new HtmlLink();
link.Href = "~/styles/main.css";
link.Attributes.Add("rel", "stylesheet");
link.Attributes.Add("type", "text/css");
Page.Header.Controls.Add(link);
}
You might need to put a runat="server" in the head tag:
<head runat="server">
<title>Add CSS example</title>
</head>
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