HtmlAgilityPack HasAttribute?

All I want to do is

node.Attributes["class"].Value

But if the node doesn't have the class attribute, it crashes. So, I have to check for its existence first, right? How do I do that? Attributes is not a dict (its a list tha开发者_Python百科t contains an internal dict??), and there's no HasAttribute method (just a HasAttributes which indicates if it has any attribute at all). What do I do?

Updated answer

Use node.Attributes["class"]?.Value to return null if the attribute is missing. This will be the same as the ValueOrDefault() below.

Original answer

Try this:

String val;
if(node.Attributes["class"] != null)
{
  val = node.Attributes["class"].Value;
}

Or you might be able to add this

public static class HtmlAgilityExtender
{
    public static String ValueOrDefault(this HtmlAttribute attr)
    {
        return (attr != null) ? attr.Value : String.Empty;
    }
}

And then use

node.Attributes["class"].ValueOrDefault();

I havent tested that one, but it should work.

Please try this:

String abc = String.Empty;     
      if (tag.Attributes.Contains(@"type"))
      {
          abc = tag.Attributes[@"type"].Value;
      }

This Code Can Be Used to get all text between two script tags.

String getURL(){
return @"some site address";
}
List<string> Internalscripts()
    {
        HtmlAgilityPack.HtmlDocument doc = new HtmlWeb().Load((@"" + getURL()));
        //Getting All the JavaScript in List
        HtmlNodeCollection javascripts = doc.DocumentNode.SelectNodes("//script");
        List<string> scriptTags = new List<string>();
        foreach (HtmlNode script in javascripts)
        {
            if(!script.Attributes.Contains(@"src"))
            {
                scriptTags.Add(script.InnerHtml);
            }
        }
        return scriptTags;
    }

HTML Agility Pack has the capability to check if a node has a particular class or provide a list of all classes.

    //Select nodes example, get all <p> tag nodes and check if they have a class and if they do, get the class attribute.
foreach (HtmlNode node in htmlAgilityDocument.DocumentNode.SelectNodes("//p"))
{
    if (node.HasClass("ClassName"))
    {
        HtmlAttribute classAttributes = node.Attributes["ClassName"];
        //Do something ...
    }
}

//Select nodes example, get all <p> tag nodes having a specified class name.
string className = "class";
foreach (HtmlNode node in htmlAgilityDocument.DocumentNode.SelectNodes("//p[@class='" + className + "']"))
{
    //Access via class attribute
    HtmlAttribute classAttribute = node.Attributes[className];
    //Do something ...
}

//Get all class names to check for a class
bool containsClass = htmlAgilityDocument.DocumentNode.GetClasses().Contains("ClassName");
if (containsClass == true)
{
    //Do something ...
}