c# - 如何使用正则表达式删除一些没有特定属性的 css 属性？

Question

示例：只保留颜色属性。

鉴于：

<span style="margin-left: 2em;color: #008000;font-size:14px;">some text</span>

输出：

<span style="color: #008000;">some text</span>

Answer 1

This answer was written on the assumption that JavaScript was being used. While this answer is still useful (under that assumption) the language has since been specified as C#. So this answer has become incorrect.

---

Given the HTML:

<span style="margin-left: 2em;color: #008000;font-size:14px;">some text</span>

The following JavaScript should work (currently untested):

var spans = document.getElementsByTagName('span'),
    color;

for (var i=0,len=spans.length;i<len;i++){
    color = spans[i].style.color;
    spans[i].removeAttribute('style');
    spans[i].style.color = color;
}​

JS Fiddle demo.

Answer 2

这是使用 Xml.Linq 的解决方案草图：

XElement Load(string xml)
{
    using (var reader = new StringReader(xml))
        return XElement.Load(reader);
}

string ProcessStyles(string input)
{
    var root = Load(input);
    var allElements = root.Descendants();
    var styleAttributes = allElements.Select(e => e.Attribute(XName.Get("style"))).Where(a => a != null);
    foreach (var styleAttribute in styleAttributes)
    {
        var value = styleAttribute.Value;
        var newValue = ProcessCss(value);
        styleAttribute.SetValue(newValue);
    }

    return root.ToString();
}

string ProcessCss(string value)
{
    var cssTokens = value.Split(';').Select(t => t.Trim());

    // implement your filtering rules here
    var filtered = cssTokens.Where(t => t.StartsWith("color"));

    return String.Join(";", filtered);
}

该解决方案假定“样式”属性的某些结构。它不适用于更复杂的 CSS（例如，带有注释）。

另请注意，输入字符串必须是格式良好的 XML 文档。（HTML5 通常不必是格式良好的 XML）。

Answer 3

如果您确实想使用正则表达式来完成这项工作，这里有一些代码片段；但我仍然建议你用styleobject 来处理这个问题。

搜索style=\"[^\"]*?([cC]olor:\s#[0-9a-fA-F]{1,6};?)[^\"]*?\"

用。。。来代替style="$1"