ASP.NET - 如何包括CSS只有不alrealy包括它？ [英] ASP.NET - How to include CSS only if it isn't alrealy included?

问题描述

我用code波纹管动态包含一个CSS文件：

  HtmlHead头=（HtmlHead）Page.Header;
HtmlLink链接=新HtmlLink（）;
link.Attributes.Add（的href，Page.ResolveClientUrl（〜/ App_Themes文件/默认/ stylesheet.css中））;
link.Attributes.Add（型，文/ CSS）;
link.Attributes.Add（相对，样式）;
head.Controls.Add（链接）;
 

的问题是：我想这样做仅一次，且仅当它不alrealy包含在页面

。

我如何验证是否已经包含它？

编辑：

答案告诉我，在页面加载到包括使用！的IsPostBack 将不解决我的问题，因为这code将是一个Web用户控件和我的内页可能有很多相同的用户控制。

例如，我使用下面的code使用JavaScript来做到这一点：

 如果（！Page.ClientScript.IsClientScriptIncludeRegistered（jsScript））
{
    Page.ClientScript.RegisterClientScriptInclude（jsScript，RESOLVEURL（〜/工具/ myScript.js））;
}
 

解决方案

做到了......

在code我用如下：

 布尔cssAlrealyIncluded = FALSE;
        HtmlLink linkAtual;
        的foreach（在Page.Header.Controls控制CTRL）
        {
            如果（ctrl.GetType（）== typeof运算（HtmlLink））
            {
                linkAtual =（HtmlLink）CTRL;                如果（linkAtual.Attributes [HREF]。载有（datePicker.css））
                {
                    cssAlrealyIncluded = TRUE;
                }
            }
        }        如果（！cssAlrealyIncluded）
        {
            HtmlLink链接=新HtmlLink（）;
            link.Attributes.Add（的href，RESOLVEURL（〜/公共事业/ datePickerRsx / datePicker.css））;
            link.Attributes.Add（型，文/ CSS）;
            link.Attributes.Add（相对，样式）;
            Page.Header.Controls.Add（链接）;
        }
 

I use the code bellow to dynamically include a CSS file:

HtmlHead head = (HtmlHead)Page.Header;
HtmlLink link = new HtmlLink();
link.Attributes.Add("href", Page.ResolveClientUrl("~/App_Themes/Default/StyleSheet.css"));
link.Attributes.Add("type", "text/css");
link.Attributes.Add("rel", "stylesheet");
head.Controls.Add(link);

The problem is: I want to do it only once, and only if it isn't alrealy included in the page.

How do I verify if it is already included?

Edit:

Answers telling me to include in page load using !IsPostBack won't solve my problem, as this code will be inside a Web User Control and my page may have a lot of the same user control.

For example, I use the code below to do it with javascript:

if (!Page.ClientScript.IsClientScriptIncludeRegistered("jsScript"))
{
    Page.ClientScript.RegisterClientScriptInclude("jsScript", ResolveUrl("~/Utilities/myScript.js"));
}

解决方案

Did it...

the code I used is as follows:

        Boolean cssAlrealyIncluded = false;
        HtmlLink linkAtual;
        foreach (Control ctrl in Page.Header.Controls)
        {
            if (ctrl.GetType() == typeof(HtmlLink))
            {
                linkAtual = (HtmlLink)ctrl;

                if (linkAtual.Attributes["href"].Contains("datePicker.css"))
                {
                    cssAlrealyIncluded = true;
                }
            }
        }

        if (!cssAlrealyIncluded)
        {
            HtmlLink link = new HtmlLink();
            link.Attributes.Add("href", ResolveUrl("~/Utilities/datePickerRsx/datePicker.css"));
            link.Attributes.Add("type", "text/css");
            link.Attributes.Add("rel", "stylesheet");
            Page.Header.Controls.Add(link);
        }

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