Hashtable VB.NET Reference Documentation

Hashtable

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

Object Creation

Dim obj As New Chilkat.Hashtable()

Properties

Count
Count As Integer (ReadOnly)
Introduced in version 9.5.0.97

The number of items (strings/integers) contained in the hash table.

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DebugLogFilePath
DebugLogFilePath As String

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.

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LastErrorHtml
LastErrorHtml As String (ReadOnly)

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.

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LastErrorText
LastErrorText As String (ReadOnly)

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.

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LastErrorXml
LastErrorXml As String (ReadOnly)

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.

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LastMethodSuccess
LastMethodSuccess As Boolean

Indicates the success or failure of the most recent method call: True means success, False 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.

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VerboseLogging
VerboseLogging As Boolean

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.

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Version
Version As String (ReadOnly)

Version of the component/library, such as "10.1.0"

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Methods

AddFromXmlSb
Function AddFromXmlSb(ByVal sbXml As StringBuilder) As Boolean
Introduced in version 9.5.0.64

Adds to the hash table from XML previously created by calling ToXmlSb.

Returns True for success, False for failure.

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AddInt
Function AddInt(ByVal key As String, ByVal value As Integer) As Boolean
Introduced in version 9.5.0.51

Adds or replaces an entry with the given key and integer value to the hash table. Returns True if a new hash entry was added or replaced. Returns False if an out-of-memory condition occurred.

Returns True for success, False for failure.

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AddQueryParams
Function AddQueryParams(ByVal queryParams As String) As Boolean
Introduced in version 9.5.0.62

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 True for success, False for failure.

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AddStr
Function AddStr(ByVal key As String, ByVal value As String) As Boolean
Introduced in version 9.5.0.51

Adds or replaces an entry with the given key and string value to the hash table. Returns True if a new hash entry was added or replaced. Returns False if an out-of-memory condition occurred.

Returns True for success, False for failure.

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Clear
Sub Clear()
Introduced in version 9.5.0.51

Removes all elements from the Hashtable.

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ClearWithNewCapacity
Function ClearWithNewCapacity(ByVal capacity As Integer) As Boolean
Introduced in version 9.5.0.51

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 True for success, False for failure.

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Contains
Function Contains(ByVal key As String) As Boolean
Introduced in version 9.5.0.51

Determines if a given key is contained within the hash table. Returns True if the key exists, otherwise returns False.

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ContainsIntKey
Function ContainsIntKey(ByVal key As Integer) As Boolean
Introduced in version 9.5.0.64

Determines if a given key is contained within the hash table. Returns True if the key exists, otherwise returns False.

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GetKeys
Function GetKeys(ByVal strTable As StringTable) As Boolean
Introduced in version 9.5.0.62

Appends the complete set of hashtable key strings to strTable.

Returns True for success, False for failure.

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LookupInt
Function LookupInt(ByVal key As String) As Integer
Introduced in version 9.5.0.51

Returns the integer value associated with the specified key. If the key is not in the hash table, the return value is 0.

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LookupStr
Function LookupStr(ByVal key As String) As String
Introduced in version 9.5.0.51

Returns the string value associated with the specified key.

Returns Nothing on failure

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Remove
Function Remove(ByVal key As String) As Boolean
Introduced in version 9.5.0.51

Removes the entry with the specified key from the hash table. Returns True if the key existed and was removed. Returns False if the key did not already exist.

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ToQueryString
Function ToQueryString() As String
Introduced in version 9.5.0.92

Serializes the hash table to a query string such as key1=value1&key2=value2&key3=value3 where each value is URL encoded.

Returns Nothing on failure

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ToXmlSb
Function ToXmlSb(ByVal sbXml As StringBuilder) As Boolean
Introduced in version 9.5.0.64

Serializes the hash table to XML format. The XML is appended to sbXml.

Returns True for success, False for failure.

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