HtmlToXml C# Reference Documentation

HtmlToXml

Class for converting HTML to well-formed XML for the purpose of programmatically extracting (scraping) information from any HTML page.

Object Creation

Chilkat.HtmlToXml obj = new Chilkat.HtmlToXml();

Properties

public string DebugLogFilePath {get; set; }

If set to a file path, causes each Chilkat method or property call to automatically append it's LastErrorText to the specified log file. The information is appended such that if a hang or crash occurs, it is possible to see the context in which the problem occurred, as well as a history of all Chilkat calls up to the point of the problem. The VerboseLogging property can be set to provide more detailed information.

This property is typically used for debugging the rare cases where a Chilkat method call hangs or generates an exception that halts program execution (i.e. crashes). A hang or crash should generally never happen. The typical causes of a hang are:

  1. a timeout related property was set to 0 to explicitly indicate that an infinite timeout is desired,
  2. the hang is actually a hang within an event callback (i.e. it is a hang within the application code), or
  3. there is an internal problem (bug) in the Chilkat code that causes the hang.

public bool DropCustomTags {get; set; }

If set to true, then any non-standard HTML tags will be dropped when converting to XML.

public string Html {get; set; }

The HTML to be converted by the ToXml method. To convert HTML to XML, first set this property to the HTML string and then call ToXml. The ConvertFile method can do file-to-file conversions.

public string LastErrorHtml {get; }

Provides information in HTML format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

public string LastErrorText {get; }

Provides information in plain-text format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

Concept of LastErrorText

LastErrorText Standard Information

public string LastErrorXml {get; }

Provides information in XML format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

public bool LastMethodSuccess {get; set; }

Introduced in version 9.5.0.52

Indicate whether the last method call succeeded or failed. A value of true indicates success, a value of false indicates failure. This property is automatically set for method calls. It is not modified by property accesses. The property is automatically set to indicate success for the following types of method calls:

  • Any method that returns a string.
  • Any method returning a Chilkat object, binary bytes, or a date/time.
  • Any method returning a standard boolean status value where success = true and failure = false.
  • Any method returning an integer where failure is defined by a return value less than zero.

Note: Methods that do not fit the above requirements will always set this property equal to true. For example, a method that returns no value (such as a "void" in C++) will technically always succeed.

public int Nbsp {get; set; }

Determines how to handle   HTML entities. The default value, 0 will cause   entites to be convert to normal space characters (ASCII value 32). If this property is set to 1, then  's will be converted to &#160. If set to 2, then &nbps;'s are dropped. If set to 3, then &nbsp's are left unmodified.

public bool VerboseLogging {get; set; }

If set to true, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is false. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.

public string Version {get; }

Version of the component/library, such as "9.5.0.63"

public string XmlCharset {get; set; }

The charset, such as "utf-8" or "iso-8859-1" of the XML to be created. If XmlCharset is empty, the XML is created in the same character encoding as the HTML. Otherwise the HTML is converted XML and converted to this charset.

Methods

public bool ConvertFile(string inHtmlPath, string destXmlPath);

Converts an HTML file to a well-formed XML file that can be parsed for the purpose of programmatically extracting information.

Returns true for success, false for failure.

public void DropTagType(string tagName);

Allows for any specified tag to be dropped from the output XML. To drop more than one tag, call this method once for each tag type to be dropped.

public void DropTextFormattingTags();

Causes text formatting tags to be dropped from the XML output. Text formatting tags are: b, font, i, u, br, center, em, strong, big, tt, s, small, strike, sub, and sup.

public bool IsUnlocked();

Returns true if the component is already unlocked. Otherwise returns false.

public byte[] ReadFile(string path);

Convenience method for reading a complete file into a byte array.

Returns an empty byte array on failure

public string ReadFileToString(string filename, string srcCharset);

Convenience method for reading a text file into a string. The character encoding of the text file is specified by srcCharset. Valid values, such as "iso-8895-1" or "utf-8" are listed at: List of Charsets.

Returns null on failure

public bool SaveLastError(string path);

Saves the last-error information (the contents of LastErrorXml) to an XML formatted file.

Returns true for success, false for failure.

public void SetHtmlBytes(byte[] inData);

Sets the Html property from a byte array.

public bool SetHtmlFromFile(string filename);

Sets the Html property by loading the HTML from a file.

Returns true for success, false for failure.

public string ToXml();

Converts the HTML in the "Html" property to XML and returns the XML string.

Returns null on failure

(C#) Convert an HTML Table to Plain-Text

(Mono C#) Convert an HTML Table to Plain-Text

(.NET Core C#) Convert an HTML Table to Plain-Text

(PowerShell) Convert an HTML Table to Plain-Text

public void UndropTagType(string tagName);

Causes a specified type of tag to NOT be dropped in the output XML.

public void UndropTextFormattingTags();

Causes text formatting tags to NOT be dropped from the XML output. Text formatting tags are: b, font, i, u, br, center, em, strong, big, tt, s, small, strike, sub, and sup.

Important: Text formatting tags are dropped by default. Call this method to prevent text formatting tags from being dropped.

public bool UnlockComponent(string unlockCode);

Unlocks the component. An arbitrary unlock code may be passed to automatically begin a 30-day trial.

Returns true for success, false for failure.

Diagnosing UnlockComponent Problems

UnlockComponent LastErrorText shows exact string passed to it.

Verify UnlockComponent Success w/ Purchased Unlock Code

LastErrorText Standard Information

public bool WriteFile(string path, byte[] fileData);

Convenience method for saving a byte array to a file.

Returns true for success, false for failure.

public bool WriteStringToFile(string stringToWrite, string filename, string charset);

Convenience method for saving a string to a file. The character encoding of the output text file is specified by charset (the string is converted to this charset when writing). Valid values, such as "iso-8895-1" or "utf-8" are listed at: List of Charsets.

Returns true for success, false for failure.