Hashtable VB.NET Reference Documentation

Hashtable

Current Version: 10.0.0

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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LastMethodSuccess
LastMethodSuccess As Boolean

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.

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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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