Hashtable VB.NET Reference Documentation

Hashtable

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

LastMethodSuccess As Boolean

Introduced in version 9.5.0.52

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

Methods

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.

Serialize / Deserialize Hashtable to/from XML

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.

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.

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.

Sub Clear()

Introduced in version 9.5.0.51

Removes all elements from the Hashtable.

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.

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.

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.

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.

Serialize / Deserialize Hashtable to/from XML

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.

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

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.

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.

Serialize / Deserialize Hashtable to/from XML