TChilkatAtom Delphi ActiveX Reference Documentation

TChilkatAtom

Current Version: 9.5.0.73

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.

Two things are required to use an ActiveX in Delphi:

  1. 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.
  2. See also: ActiveX Registration Tutorial
  3. 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_v9_5_0_TLB.pas and Chilkat_v9_5_0_TLB.dcr. The Chilkat_v9_5_0_TLB.pas should be added to your project.

To import the Chilkat type library, do the following:

  1. In the Delphi RAD Studio, select the menu item "Component" --> "Import a Type Library".
  2. Find "Chilkat ActiveX v9.5.0" in the list and select it. This will only appear in the list if the ChilkatAx-9.5.0-win32.dll (or ChilkatAx-9.5.0-x64.dll) has been registered w/ regsvr32.
  3. Check the "Generate Component Wrappers" checkbox.
  4. Select a directory where the unit files (.pas and .dcr) should be generated.
  5. Select "Create Unit" and then "Finish".
  6. Add the .pas to your Delphi project.

To use a Chilkat ActiveX object in your Delphi code, add "Chilkat_v9_5_0_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_v9_5_0_TLB;

Object Creation

var
obj: TChilkatAtom;
...
begin
obj := TChilkatAtom.Create(Self);
...
// When finished, free the object instance.
obj.Free();

Properties

AbortCurrent
property AbortCurrent: Integer readonly
Introduced in version 9.5.0.58

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.)

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DebugLogFilePath
property DebugLogFilePath: WideString

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.

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LastBinaryResult
property LastBinaryResult: OleVariant readonly
Introduced in version 9.5.0.52

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).

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LastErrorHtml
property LastErrorHtml: WideString readonly

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.

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LastErrorText
property LastErrorText: WideString readonly

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.

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LastErrorXml
property LastErrorXml: WideString readonly

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.

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LastMethodSuccess
property LastMethodSuccess: Integer
Introduced in version 9.5.0.52

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.

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LastStringResult
property LastStringResult: WideString readonly
Introduced in version 9.5.0.52

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).

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LastStringResultLen
property LastStringResultLen: Integer readonly
Introduced in version 9.5.0.53

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

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NumEntries
property NumEntries: Integer readonly

Number of entries in the Atom document.

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VerboseLogging
property VerboseLogging: Integer

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.

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Version
property Version: WideString readonly

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

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Methods

AddElement
function AddElement(tag: WideString; value: WideString): Integer;

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.

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AddElementDate
function AddElementDate(tag: WideString; dateTime: TDateTime): Integer;
This method is deprecated. It will be removed in a future version.

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.

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AddElementDateStr
function AddElementDateStr(tag: WideString; dateTimeStr: WideString): Integer;

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.

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AddElementDt
function AddElementDt(tag: WideString; dateTime: TCkDateTime): Integer;

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.

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AddElementHtml
function AddElementHtml(tag: WideString; htmlStr: WideString): Integer;

Adds a new HTML formatted element to the Atom document. Returns the index of the element added, or -1 for failure.

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AddElementXHtml
function AddElementXHtml(tag: WideString; xmlStr: WideString): Integer;

Adds a new XHTML formatted element to the Atom document. Returns the index of the element added, or -1 for failure.

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AddElementXml
function AddElementXml(tag: WideString; xmlStr: WideString): Integer;

Adds a new XML formatted element to the Atom document. Returns the index of the element added, or -1 for failure.

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AddEntry
procedure AddEntry(xmlStr: WideString);

Adds an "entry" Atom XML document to the caller's Atom document.

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AddLink
procedure AddLink(rel: WideString; href: WideString; title: WideString; typ: WideString);

Adds a link to the Atom document.

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AddPerson
procedure AddPerson(tag: WideString; name: WideString; uri: WideString; email: WideString);

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.

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DeleteElement
procedure DeleteElement(tag: WideString; index: Integer);

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.

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DeleteElementAttr
procedure DeleteElementAttr(tag: WideString; index: Integer; attrName: WideString);

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 ).

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DeletePerson
procedure DeletePerson(tag: WideString; index: Integer);

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.

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DownloadAtom
function DownloadAtom(url: WideString): Integer;

Download an Atom feed from the Internet and load it into the Atom object.

Returns 1 for success, 0 for failure.

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DownloadAtomAsync (1)
function DownloadAtomAsync(url: WideString): TChilkatTask;

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

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GetElement
function GetElement(tag: WideString; index: Integer): WideString;

Returns the content of the Nth element having a specified tag.

Returns a zero-length WideString on failure

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GetElementAttr
function GetElementAttr(tag: WideString; index: Integer; attrName: WideString): WideString;

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

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GetElementCount
function GetElementCount(tag: WideString): Integer;

The number of elements having a specific tag.

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GetElementDate
function GetElementDate(tag: WideString; index: Integer): TDateTime;
This method is deprecated. It will be removed in a future version.

Returns an element's value as a date/time.

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GetElementDateStr
function GetElementDateStr(tag: WideString; index: Integer): WideString;

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

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GetElementDt
function GetElementDt(tag: WideString; index: Integer): TCkDateTime;

Returns an element's value as a date/time object.

Returns nil on failure

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GetEntry
function GetEntry(index: Integer): TChilkatAtom;

Returns the Nth entry as an Atom object. (Indexing begins at 0)

Returns nil on failure

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GetLinkHref
function GetLinkHref(relName: WideString): WideString;

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

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GetPersonInfo
function GetPersonInfo(tag: WideString; index: Integer; tag2: WideString): WideString;

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

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GetTopAttr
function GetTopAttr(attrName: WideString): WideString;

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

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HasElement
function HasElement(tag: WideString): Integer;

True (1) if the element exists in the Atom document. Otherwise 0.

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LoadXml
function LoadXml(xmlStr: WideString): Integer;

Loads the Atom document from an XML string.

Returns 1 for success, 0 for failure.

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NewEntry
procedure NewEntry();

Initializes the Atom document to be a new "entry".

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NewFeed
procedure NewFeed();

Initializes the Atom document to be a new "feed".

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SetElementAttr
procedure SetElementAttr(tag: WideString; index: Integer; attrName: WideString; attrValue: WideString);

Adds or replaces an attribute on an element.

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SetTopAttr
procedure SetTopAttr(attrName: WideString; value: WideString);

Adds or replaces an attribute on the top-level XML node of the Atom document.

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ToXmlString
function ToXmlString(): WideString;

Serializes the Atom document to an XML string.

Returns a zero-length WideString on failure

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UpdateElement
procedure UpdateElement(tag: WideString; index: Integer; value: WideString);

Replaces the content of an element.

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UpdateElementDate
procedure UpdateElementDate(tag: WideString; index: Integer; dateTime: TDateTime);
This method is deprecated. It will be removed in a future version.

Replaces the content of a date-formatted element.

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UpdateElementDateStr
procedure UpdateElementDateStr(tag: WideString; index: Integer; dateTimeStr: WideString);

Replaces the content of a date-formatted element. The index should be an RFC822 formatted date/time string.

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UpdateElementDt
procedure UpdateElementDt(tag: WideString; index: Integer; dateTime: TCkDateTime);

Replaces the content of a date-formatted element.

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UpdateElementHtml
procedure UpdateElementHtml(tag: WideString; index: Integer; htmlStr: WideString);

Replaces the content of an HTML element.

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UpdateElementXHtml
procedure UpdateElementXHtml(tag: WideString; index: Integer; xmlStr: WideString);

Replaces the content of an XHTML element.

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UpdateElementXml
procedure UpdateElementXml(tag: WideString; index: Integer; xmlStr: WideString);

Replaces the content of an XML element.

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UpdatePerson
procedure UpdatePerson(tag: WideString; index: Integer; name: WideString; uri: WideString; email: WideString);

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.

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Events

AbortCheck
procedure AbortCheck(ASender: TObject; out abort: Integer);

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.atomENTRY_NAME(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;
  // ...
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PercentDone
procedure PercentDone(ASender: TObject; pctDone: Integer; out abort: Integer);

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.atomENTRY_NAME(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;
  // ...
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ProgressInfo
procedure ProgressInfo(ASender: TObject; const name: WideString; const value: WideString);

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.atomENTRY_NAME(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;
  // ...
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TaskCompleted
procedure TaskCompleted(ASender: TObject; const task: IChilkatTask);

Called in the background thread when an asynchronous task completes.

More Information and Examples

Delphi ActiveX Event callback implementation:

procedure TForm1.atomENTRY_NAME(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;
  // ...
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