Hashtable Delphi ActiveX Reference Documentation
TChilkatHashtable
Current Version: 11.0.0
Represents a collection of key/value pairs that are stored in a hash table.
Note: This class was added in Chilkat v9.5.0.51
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: TChilkatHashtable; ... begin obj := TChilkatHashtable.Create(Self); ... // When finished, free the object instance. obj.Free();
Properties
Count
The number of items (strings/integers) contained in the hash table.
topDebugLogFilePath
If set to a file path, this property logs the LastErrorText of each Chilkat method or property call to the specified file. This logging helps identify the context and history of Chilkat calls leading up to any crash or hang, aiding in debugging.
Enabling the VerboseLogging property provides more detailed information. This property is mainly used for debugging rare instances where a Chilkat method call causes a hang or crash, which should generally not happen.
Possible causes of hangs include:
- A timeout property set to 0, indicating an infinite timeout.
- A hang occurring within an event callback in the application code.
- An internal bug in the Chilkat code causing the hang.
LastBinaryResult
This property is mainly used in SQL Server stored procedures to retrieve binary data from the last method call that returned binary data. It is only accessible if Chilkat.Global.KeepBinaryResult is set to 1. This feature allows for the retrieval of large varbinary results in an SQL Server environment, which has restrictions on returning large data via method calls, though temp tables can handle binary properties.
LastErrorHtml
Provides HTML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.
topLastErrorText
Provides plain text information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.
LastErrorXml
Provides XML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.
topLastMethodSuccess
Indicates the success or failure of the most recent method call: 1 means success, 0 means failure. This property remains unchanged by property setters or getters. This method is present to address challenges in checking for null or Nothing returns in certain programming languages.
LastStringResult
In SQL Server stored procedures, this property holds the string return value of the most recent method call that returns a string. It is accessible only when Chilkat.Global.KeepStringResult is set to TRUE. SQL Server has limitations on string lengths returned from methods and properties, but temp tables can be used to access large strings.
LastStringResultLen
The length, in characters, of the string contained in the LastStringResult property.
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.
Version
Methods
AddFromXmlSb
Adds to the hash table from XML previously created by calling ToXmlSb.
Returns 1 for success, 0 for failure.
AddInt
Adds or replaces an entry with the given key and integer value to the hash table. Returns 1 if a new hash entry was added or replaced. Returns 0 if an out-of-memory condition occurred.
Returns 1 for success, 0 for failure.
topAddQueryParams
Adds URL query parameters into the hashtable. The queryParams has the form: "field1=value1&field2=value2&field3=value3...". It is assumed that the values are URL encoded, and this method automatically URL decodes the values prior to inserting into the hashtable.
Returns 1 for success, 0 for failure.
AddStr
Adds or replaces an entry with the given key and string value to the hash table. Returns 1 if a new hash entry was added or replaced. Returns 0 if an out-of-memory condition occurred.
Returns 1 for success, 0 for failure.
topClear
Removes all elements from the Hashtable.
topClearWithNewCapacity
Removes all elements from the Hashtable and re-sizes with the specified capacity.
The capacity is the number of buckets in the hash table. In the case of a "hash collision", a single bucket stores multiple entries, which must be searched sequentially. One rule of thumb is to set the capacity to twice the number of expected items to be hashed. It's also preferable to set the capacity to a prime number. (The 1st 10,000 prime numbers are listed here: https://primes.utm.edu/lists/small/10000.txt )
The initial default capacity of the hash table is 521.
Returns 1 for success, 0 for failure.
topContains
Determines if a given key is contained within the hash table. Returns 1 if the key exists, otherwise returns 0.
ContainsIntKey
Determines if a given key is contained within the hash table. Returns 1 if the key exists, otherwise returns 0.
GetKeys
Appends the complete set of hashtable key strings to strTable.
Returns 1 for success, 0 for failure.
LookupInt
Returns the integer value associated with the specified key. If the key is not in the hash table, the return value is 0.
topLookupStr
Returns the string value associated with the specified key.
Returns a zero-length WideString on failure
topRemove
Removes the entry with the specified key from the hash table. Returns 1 if the key existed and was removed. Returns 0 if the key did not already exist.
ToQueryString
Serializes the hash table to a query string such as key1=value1&key2=value2&key3=value3 where each value is URL encoded.
Returns a zero-length WideString on failure
ToXmlSb
Serializes the hash table to XML format. The XML is appended to sbXml.
Returns 1 for success, 0 for failure.