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extracting the letter in between tags
okie let me give an example we have a file,where i need to open it in c# and scan and extract information ,like i want hi to be extracted which is between tag so only i want that to be extracted and copied to other file ,so what can i do??....and how to start about
<REFER> abcd</REFER>
<BODY>hi</BODY>
<p1>hello</p1>
You probably want to use an HTML-Parser (pick one) and then use it to retrieve the content between the tags.
Well, I'd start with looking in the System.IO namespace in order to learn how to read and write files...
Your data looks like it may be XML, so look at the XmlDocument class in System.Xml or the Linq XDocument class. If it's not XML then you're going to have to parse it yourself, so read up on the String class.
Well, this may be a trivial example, but if your document structure gets any more complex than this, I'd highly recommend HtmlAgilityPack.
For the example given, you'd use it like this:
string html = "<REFER> abcd</REFER><BODY>hi</BODY><p1>hello</p1>";
var doc = new HtmlDocument();
doc.LoadHtml(html);
HtmlNode root = doc.DocumentElement;
HtmlNode body = root.SelectSingleNode("BODY");
string extracted = body.InnerText;
That may seem like overkill; but like I said, if the document structure gets any more complex (I can't imagine that the documents you'll be parsing really look like the example), you'll be glad you did it.
Related
i want to copy or clone a specific node or Element from XML. I tried many codes, but no one worked. I am program with C#.
Here is my XML, I hope my problem is clear!
This is my XML before
I want this XML
I can´t do this manually, because I need more than 30 Tools more.
it really depends on what you are using to parse the xml.
I will give you info for the two most used classes for parsing an xml in .NET.
XmlDocument: then you can use .CloneNode
XDocument: then you can do something like this:
XElement toCopy = ...;
XElement copy = XElement.Parse(toCopy.ToString());
If you are not familiar with xml processing in .NET, there is enough information in msdn for XDocument and XmlDocument.
I have a string:
<div class="className1234"><p>Some html</p></div>
From this string, I would like to get <p>Some html</p> i.e. I would like to remove the surrounding div tags based on the fact that it's class contains 'className'.
What I've Tried
What I've tried works, but it's cludgey - and I know there'll be a better alternative like regex or something. What I currently do is chain a series of substring(), indexof() and replace() calls to strip out the divs.
EDIT: I've used the phrase 'innerhtml' because I'd like to think there's a library out there somewhere that would allow me to manipulate a string with regard to the tags within it.
PLEASE NOTE: There's no JQuery involved in this. It's all server-side C#.
(See tags)
I would suggest Html Agility Pack, it's designed to allow operations on html documents, kind of like the builtin support for XML in the framework.
It might be overkill, but it will get the work done, easily, and you won't have to care about bad html
How about:
XmlDocument doc = new XmlDocument();
doc.LoadXml(divStr);
// classAtr will be null if the root is not a div with a class with the value className1234
XmlNode classAtr = doc.SelectSingleNode("/div/#class[contains(., 'className1234')]");
string result = classAtr != null ? doc.DocumentElement.InnerXml : divStr;
Whenever you need to manipulate HTML, you should use a dedicated HTML parser/DOM library. One library I've found recommended here on StackOverflow for .Net is HTMLAgilityPack.
As others said HtmlAgilityPack is the best for html parsing, also be sure to download HAP Explorer from HtmlAgilityPack site, use it to test your selects, anyway this SelectNode command will get :
HtmlDocument doc = new HtmlDocument();
doc.Load(htmlFile);
var myNodes = doc.DocumentNode.SelectNodes("/div/#class[. = 'className1234']");
foreach (HtmlNode node in myNodes)
{
// you code
}
I'm trying to get a list of PDF links from different websites. First I'm using the Web client class to download the page source. I then use sgmlReader to convert the HTML to XML. So for one particular site, I'll get a tag that looks like this:
<p>1985 to 1997 Board Action Summary</p>
I need to grab all the links that contain ".pdf". Obviously not all websites are laid out the same, so just searching for a <p> tag, wont be dynamic enough. I'd rather not use linq, but I will if I have to. Thanks in advance.
Linq makes this easy...
var hrefs = doc.Root.Descendants("a")
.Where(a => a.Attrib("href").Value.ToUpper().EndsWith(".PDF"))
.Select(a => a.Attrib("href"));
away you go! (note: did this from memory, so you might have to fix it somewhat)
This will break down for <a/> tags that don't have an href (anchors) but you can fix that surely...
I think you have 2 options here. If you need only the links, you can use Regular Expressions to find the matches for strings ending with .pdf. If you need to manipulate the XML structure or get other values from the XML, it would be better to use XmlDocument and use an XPath query to find out the nodes which have a link to a pdf file in it. Using LINQ to XML just reduces the number of lines of code you have to write.
Knowing that I can't use HTMLAgilityPack, only straight .NET, say I have a string that contains some HTML that I need to parse and edit in such ways:
find specific controls in the hierarchy by id or by tag
modify (and ideally create) attributes of those found elements
Are there methods available in .net to do so?
HtmlDocument
GetElementById
HtmlElement
You can create a dummy html document.
WebBrowser w = new WebBrowser();
w.Navigate(String.Empty);
HtmlDocument doc = w.Document;
doc.Write("<html><head></head><body><img id=\"myImage\" src=\"c:\"/><a id=\"myLink\" href=\"myUrl\"/></body></html>");
Console.WriteLine(doc.Body.Children.Count);
Console.WriteLine(doc.GetElementById("myImage").GetAttribute("src"));
Console.WriteLine(doc.GetElementById("myLink").GetAttribute("href"));
Console.ReadKey();
Output:
2
file:///c:
about:myUrl
Editing elements:
HtmlElement imageElement = doc.GetElementById("myImage");
string newSource = "d:";
imageElement.OuterHtml = imageElement.OuterHtml.Replace(
"src=\"c:\"",
"src=\"" + newSource + "\"");
Console.WriteLine(doc.GetElementById("myImage").GetAttribute("src"));
Output:
file:///d:
Assuming you're dealing with well formed HTML, you could simply treat the text as an XML document. The framework is loaded with features to do exactly what you're asking.
http://msdn.microsoft.com/en-us/library/system.xml.xmldocument.aspx
Aside from the HTML Agility Pack, and porting HtmlUnit over to C#, what sounds like solid solutions are:
Most obviously - use regex. (System.Text.RegularExpressions)
Using an XML Parser. (because HTML is a system of tags treat it like an XML document?)
Linq?
One thing I do know is that parsing HTML like XML may cause you to run into a few problems. XML and HTML are not the same. Read about it: here
Also, here is a post about Linq vs Regex.
You can look at how HTML Agility Pack works, however, it is .Net. You can reflect the assembly and see that it is using the MFC and could be reproduced if you so wanted, but you'd be doing nothing more than moving the assembly, not making it any more .Net.
I'm working in Microsoft Visual C# 2008 Express.
Let's say I have a string and the contents of the string is: "This is my <myTag myTagAttrib="colorize">awesome</myTag> string."
I'm telling myself that I want to do something to the word "awesome" - possibly call a function that does something called "colorize".
What is the best way in C# to go about detecting that this tag exists and getting that attribute? I've worked a little with XElements and such in C#, but mostly to do with reading in and out XML files.
Thanks!
-Adeena
Another solution:
var myString = "This is my <myTag myTagAttrib='colorize'>awesome</myTag> string.";
try
{
var document = XDocument.Parse("<root>" + myString + "</root>");
var matches = ((System.Collections.IEnumerable)document.XPathEvaluate("myTag|myTag2")).Cast<XElement>();
foreach (var element in matches)
{
switch (element.Name.ToString())
{
case "myTag":
//do something with myTag like lookup attribute values and call other methods
break;
case "myTag2":
//do something else with myTag2
break;
}
}
}
catch (Exception e)
{
//string was not not well formed xml
}
I also took into account your comment to Dabblernl where you want parse multiple attributes on multiple elements.
You can extract the XML with a regular expression, load the extracted xml string in a XElement and go from there:
string text=#"This is my<myTag myTagAttrib='colorize'>awesome</myTag> text.";
Match match=Regex.Match(text,#"(<MyTag.*</MyTag>)");
string xml=match.Captures[0].Value;
XElement element=XElement.Parse(xml);
XAttribute attribute=element.Attribute("myTagAttrib");
if(attribute.Value=="colorize") DoSomethingWith(element.Value);// Value=awesome
This code will throw an exception if no MyTag element was found, but that can be remedied by inserting a line of:
if(match.Captures.Count!=0)
{...}
It gets even more interesting if the string could hold more than just the MyTag Tag...
I'm a little confused about your example, because you switch between the string (text content), tags, and attributes. But I think what you want is XPath.
So if your XML stream looks like this:
<adeena/><parent><child x="this is my awesome string">This is another awesome string<child/><adeena/>
You'd use an XPath expression that looks like this to find the attribute:
//child/#x
and one like this to find the text value under the child tag:
//child
I'm a Java developer, so I don't know what XML libraries you'd use to do this. But you'll need a DOM parser to create a W3C Document class instance for you by reading in the XML file and then using XPath to pluck out the values.
There's a good XPath tutorial from the W3C schools if you need it.
UPDATE:
If you're saying that you already have an XML stream as String, then the answer is to not read it from a file but from the String itself. Java has abstractions called InputStream and Reader that handle streams of bytes and chars, respectively. The source can be a file, a string, etc. Check your C# DOM API to see if it has something similar. You'll pass the string to a parser that will give back a DOM object that you can manipulate.
Since the input is not well-formed XML you won't be able to parse it with any of the built in XML libraries. You'd need a regular expression to extract the well-formed piece. You could probably use one of the more forgiving HTML parsers like HtmlAgilityPack on CodePlex.
This is my solution to match any type of xml using Regex:
C# Better way to detect XML?
The XmlTextReader can parse XML fragments with a special constructor which may help in this situation, but I'm not positive about that.
There's an in-depth article here:
http://geekswithblogs.net/kobush/archive/2006/04/20/75717.aspx