TChilkatAtom Delphi ActiveX Reference Documentation
TChilkatAtom
Current Version: 10.1.0
Represents an Atom document. The Atom API allows one to download, create and modify Atom documents.
Importing the Chilkat ActiveX into Delphi
Important: When upgrading to a new version of Chilkat, make sure to re-imported ActiveX DLL into Delphi to regenerate the files described below.
Chilkat v9.5.*: If using Chilkat v9.5.*, then use "Chilkat_v9_5_0_TLB" instead of "Chilkat_TLB", and the DLLs are named ChilkatAx-9.5.0-win32.dll (or ChilkatAx-9.5.0-x64.dll).
Two things are required to use an ActiveX in Delphi:
- The ActiveX DLL needs to be registered via regsvr32 on the system where the Delphi application runs. See How To Register ActiveX DLLs for detailed information.
- See also: ActiveX Registration Tutorial
- The ActiveX component needs to be "imported". Use the Delphi Import Component Wizard to import the Chilkat type library. This creates the following files: Chilkat_TLB.pas and Chilkat_TLB.dcr. The Chilkat_TLB.pas should be added to your project.
To import the Chilkat type library, do the following:
- In the Delphi RAD Studio, select the menu item "Component" --> "Import a Type Library".
- Find "Chilkat ActiveX" in the list and select it. This will only appear in the list if the ChilkatAx-win32.dll (or ChilkatAx-x64.dll) has been registered w/ regsvr32.
- Check the "Generate Component Wrappers" checkbox.
- Select a directory where the unit files (.pas and .dcr) should be generated.
- Select "Create Unit" and then "Finish".
- Add the .pas to your Delphi project.
To use a Chilkat ActiveX object in your Delphi code, add "Chilkat_TLB" to the "uses" statement. For example:
uses Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics, Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Chilkat_TLB;
Object Creation
var obj: TChilkatAtom; ... begin obj := TChilkatAtom.Create(Self); ... // When finished, free the object instance. obj.Free();
Properties
AbortCurrent
When set to 1, causes the currently running method to abort. Methods that always finish quickly (i.e.have no length file operations or network communications) are not affected. If no method is running, then this property is automatically reset to 0 when the next method is called. When the abort occurs, this property is reset to 0. Both synchronous and asynchronous method calls can be aborted. (A synchronous method call could be aborted by setting this property from a separate thread.)
topDebugLogFilePath
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:
- a timeout related property was set to 0 to explicitly indicate that an infinite timeout is desired,
- the hang is actually a hang within an event callback (i.e. it is a hang within the application code), or
- there is an internal problem (bug) in the Chilkat code that causes the hang.
LastBinaryResult
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).
topLastErrorHtml
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.
topLastErrorText
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.
LastErrorXml
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.
topLastMethodSuccess
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.
topLastStringResult
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).
LastStringResultLen
The length, in characters, of the string contained in the LastStringResult property.
topNumEntries
Number of entries in the Atom document.
topVerboseLogging
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.
topVersion
Methods
AddElement
Adds a new element to the Atom document. The tag is a string such as "title", "subtitle", "summary", etc. Returns the index of the element added, or -1 for failure.
topAddElementDateStr
Adds a new date-formatted element to the Atom document. The tag is a string such as "created", "modified", "issued", etc. The dateTimeStr should be an RFC822 formatted date/time string such as "Tue, 25 Sep 2012 12:25:32 -0500". Returns the index of the element added, or -1 for failure.
topAddElementDt
Adds a new date-formatted element to the Atom document. The tag is a string such as "created", "modified", "issued", etc. Returns the index of the element added, or -1 for failure.
topAddElementHtml
Adds a new HTML formatted element to the Atom document. Returns the index of the element added, or -1 for failure.
topAddElementXHtml
Adds a new XHTML formatted element to the Atom document. Returns the index of the element added, or -1 for failure.
topAddElementXml
Adds a new XML formatted element to the Atom document. Returns the index of the element added, or -1 for failure.
topAddEntry
Adds an "entry" Atom XML document to the caller's Atom document.
topAddLink
Adds a link to the Atom document.
topAddPerson
Adds a person to the Atom document. The tag should be a string such as "author", "contributor", etc. If a piece of information is not known, an empty string or NULL value may be passed.
topDeleteElement
Removes the Nth occurrence of a given element from the Atom document. Indexing begins at 0. For example, to remove the 2nd category, set tag = "category" and index = 1.
topDeleteElementAttr
Remove an attribute from an element.The index should be 0 unless there are multiple elements having the same tag, in which case it selects the Nth occurrence based on the index ( 0 = first occurrence ).
topDeletePerson
Deletes a person from the Atom document. The tag is a string such as "author". The index should be 0 unless there are multiple elements having the same tag, in which case it selects the Nth occurrence based on the index. For example, DeletePerson("author",2) deletes the 3rd author.
topDownloadAtom
Download an Atom feed from the Internet and load it into the Atom object.
Returns 1 for success, 0 for failure.
topDownloadAtomAsync (1)
Creates an asynchronous task to call the DownloadAtom 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
topGetElement
Returns the content of the Nth element having a specified tag.
Returns a zero-length WideString on failure
topGetElementAttr
Returns the value of an element's attribute. The element is selected by the tag name and the index (the Nth element having a specific tag) and the attribute is selected by name.
Returns a zero-length WideString on failure
topGetElementCount
The number of elements having a specific tag.
topGetElementDateStr
Returns an element's value as a date/time in an RFC822 formatted string, such as such as "Tue, 25 Sep 2012 12:25:32 -0500".
Returns a zero-length WideString on failure
topGetElementDt
GetEntry
GetLinkHref
Returns the href attribute of the link having a specified "rel" attribute (such as "service.feed", "alternate", etc.).
Returns a zero-length WideString on failure
topGetPersonInfo
Returns a piece of information about a person. To get the 2nd author's name, call GetPersonInfo("author",1,"name").
Returns a zero-length WideString on failure
topGetTopAttr
Returns the value of an attribute on the top-level XML node. The tag of a top-level Atom XML node is typically "feed" or "entry", and it might have attributes such as "xmlns" and "xml:lang".
Returns a zero-length WideString on failure
topHasElement
True (1) if the element exists in the Atom document. Otherwise 0.
topLoadTaskCaller
LoadXml
NewEntry
Initializes the Atom document to be a new "entry".
topNewFeed
Initializes the Atom document to be a new "feed".
topSetElementAttr
Adds or replaces an attribute on an element.
topSetTopAttr
Adds or replaces an attribute on the top-level XML node of the Atom document.
topToXmlString
UpdateElement
Replaces the content of an element.
topUpdateElementDateStr
Replaces the content of a date-formatted element. The index should be an RFC822 formatted date/time string.
topUpdateElementDt
Replaces the content of a date-formatted element.
topUpdateElementHtml
Replaces the content of an HTML element.
topUpdateElementXHtml
Replaces the content of an XHTML element.
topUpdateElementXml
Replaces the content of an XML element.
topUpdatePerson
Replaces the content of a person. To update the 3rd author, call UpdatePerson("author",2,"new name","new URL","new email"). If a piece of information is not known, pass an empty string or a NULL.
topEvents
AbortCheck
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.atomAbortCheck(ASender: TObject; out abort: Integer); begin // Application code goes here... end; procedure TForm1.Button1Click(Sender: TObject); var atom: TChilkatAtom; begin atom := TChilkatAtom.Create(Self); atom.OnAbortCheck := atomAbortCheck; // ...
PercentDone
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.atomPercentDone(ASender: TObject; pctDone: Integer; out abort: Integer); begin // Application code goes here... end; procedure TForm1.Button1Click(Sender: TObject); var atom: TChilkatAtom; begin atom := TChilkatAtom.Create(Self); atom.OnPercentDone := atomPercentDone; // ...
ProgressInfo
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.atomProgressInfo(ASender: TObject; const name: WideString; const value: WideString); begin // Application code goes here... end; procedure TForm1.Button1Click(Sender: TObject); var atom: TChilkatAtom; begin atom := TChilkatAtom.Create(Self); atom.OnProgressInfo := atomProgressInfo; // ...
TaskCompleted
Called in the background thread when an asynchronous task completes.
Delphi ActiveX Event callback implementation:
procedure TForm1.atomTaskCompleted(ASender: TObject; const task: IChilkatTask); begin // Application code goes here... end; procedure TForm1.Button1Click(Sender: TObject); var atom: TChilkatAtom; begin atom := TChilkatAtom.Create(Self); atom.OnTaskCompleted := atomTaskCompleted; // ...