TChilkatRss

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.

The binary data returned by the last (binary data returning) method called. Only available if Chilkat.Global.KeepBinaryResult is set to 1. This provides a means for obtaining large varbinary results in the SQL Server environment (where limitations exist in getting large amounts of data returned by method calls, but where temp tables can be used for binary properties).

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.

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.

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.

Indicate whether the last method call succeeded or failed. A value of 1 indicates success, a value of 0 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 = 1 and failure = 0.
• 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 1. For example, a method that returns no value (such as a "void" in C++) will technically always succeed.

The string return value of the last (string returning) method called. Only available if Chilkat.Global.KeepStringResult is set to 1. This provides a means for obtaining large string results in the SQL Server environment (where limitations exist in getting long strings returned by method calls, but where temp tables can be used for string properties).

The length, in characters, of the string contained in the LastStringResult property.

The number of channels in the RSS document.

The number of items in the channel.

If set to 1, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is 0. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.

Version of the component/library, such as "9.5.0.94"

Adds a new channel to the RSS document. Returns the Rss object representing the Channel which can then be edited.

Returns nil on failure

Adds a new image to the RSS document. Returns the Rss object representing the image, which can then be edited.

Returns nil on failure

Adds a new Item to an Rss channel. Returns the Rss object representing the item which can then be edited.

Returns nil on failure

Downloads an RSS document from the Internet and populates the Rss object with the contents.

Returns 1 for success, 0 for failure.

Creates an asynchronous task to call the DownloadRss method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

Returns the value of a sub-element attribute. For example, to get the value of the "isPermaLink" attribute of the "guid" sub-element, call item.GetAttr("guid","isPermaLink").

Returns a zero-length WideString on failure

Returns the Nth channel of an RSS document. Usually there is only 1 channel per document, so the index argument should be set to 0.

Returns nil on failure

Return the number of sub-elements with a specific tag.

The same as GetDate, except the date/time is returned in RFC822 string format.

Returns a zero-length WideString on failure

Return the image associated with the channel.

Returns nil on failure

Return the value of a numeric sub-element as an integer.

Return the Nth item of a channel as an RSS object.

Returns nil on failure

Return the value of an sub-element as a string.

Returns a zero-length WideString on failure

Load an RSS document from a file.

Returns 1 for success, 0 for failure.

Loads an RSS feed document from an in-memory string.

Returns 1 for success, 0 for failure.

Loads the caller of the task's async method.

Returns 1 for success, 0 for failure.

Get an attribute value for the Nth sub-element having a specific tag. As an example, an RSS item may have several "category" sub-elements. To get the value of the "domain" attribute for the 3rd category, call MGetAttr("category",2,"domain").

Returns a zero-length WideString on failure

Get the value of the Nth occurrence of a sub-element. Indexing begins at 0.

Returns a zero-length WideString on failure

Set an attribute on the Nth occurrence of a sub-element.

Returns 1 for success, 0 for failure.

Set the value of the Nth occurrence of a sub-element. Indexing begins at 0.

Returns 1 for success, 0 for failure.

Clears the RSS document.

Removes a sub-element from the RSS document.

Sets the value of a sub-element attribute.

Sets the value of a date/time sub-element to the current system date/time.

The same as SetDate, except the date/time is passed as an RFC822 string.

Sets the value of an integer sub-element.

Sets the value of a sub-element.

Returns the RSS document as an XML string.

Returns a zero-length WideString on failure

Provides the opportunity for a method call to be aborted. The AbortCheck event is fired periodically based on the value of the HeartbeatMs property. If HeartbeatMs is 0, then no AbortCheck events will fire. As an example, to fire 5 AbortCheck events per second, set the HeartbeatMs property equal to 200.

Delphi ActiveX Event callback implementation:

procedure TForm1.rssAbortCheck(ASender: TObject;  out abort: Integer);
begin
    // Application code goes here...
end;


procedure TForm1.Button1Click(Sender: TObject);
var
  rss: TChilkatRss;

begin
  rss := TChilkatRss.Create(Self);
  rss.OnAbortCheck := rssAbortCheck;
  // ...

Provides the percentage completed for any method that involves network communications or time-consuming processing (assuming it is a method where a percentage completion can be measured). This event is only fired when it is possible to know a percentage completion, and when it makes sense to express the operation as a percentage completed. The pctDone argument will have a value from 1 to 100. For operations (Chilkat method calls) that complete very quickly, the number of PercentDone callbacks will vary, but the final callback should have a value of 100. For long running operations, no more than one callback per percentage point will occur (for example: 1, 2, 3, ... 98, 99, 100).

The PercentDone callback counts as an AbortCheck event. For method calls that complete quickly such that PercentDone events fire, it may be that AbortCheck events don't fire because the opportunity to abort is already provided in the PercentDone callback. For time consuming operations, where the amount of time between PercentDone callbacks are long, AbortCheck callbacks may be used to allow for the operation to be aborted in a more responsive manner.

The abort output argument provides a means for aborting the operation. Setting it to 1 will cause the method to abort and return a failed status (or whatever return value indicates failure).

Delphi ActiveX Event callback implementation:

procedure TForm1.rssPercentDone(ASender: TObject;  pctDone: Integer; out abort: Integer);
begin
    // Application code goes here...
end;


procedure TForm1.Button1Click(Sender: TObject);
var
  rss: TChilkatRss;

begin
  rss := TChilkatRss.Create(Self);
  rss.OnPercentDone := rssPercentDone;
  // ...

A general name/value event that provides information about what is happening during a method call. To find out what information is available, write code to handle this event and log the name/value pairs. Most are self-explanatory.

Delphi ActiveX Event callback implementation:

procedure TForm1.rssProgressInfo(ASender: TObject;  const name: WideString; const value: WideString);
begin
    // Application code goes here...
end;


procedure TForm1.Button1Click(Sender: TObject);
var
  rss: TChilkatRss;

begin
  rss := TChilkatRss.Create(Self);
  rss.OnProgressInfo := rssProgressInfo;
  // ...

Called in the background thread when an asynchronous task completes.

Delphi ActiveX Event callback implementation:

procedure TForm1.rssTaskCompleted(ASender: TObject;  const task: IChilkatTask);
begin
    // Application code goes here...
end;


procedure TForm1.Button1Click(Sender: TObject);
var
  rss: TChilkatRss;

begin
  rss := TChilkatRss.Create(Self);
  rss.OnTaskCompleted := rssTaskCompleted;
  // ...