Properties and Methods of the Hashtable Class

Item	Description
Properties
Count	Contains the number of items currently in the hashtable
IsReadOnly	Contains True if the hashtable is read-only and False otherwise
IsSynchronized	Contains True if the hashtable is synchronized and False otherwise
Item[]	Contains an index of all the items in the hashtable
Keys	Contains a collection of all the keys in the hashtable
Values	Contains a collection of all the values in the hashtable
Methods
Add()	Adds an item to the hashtable
Clear()	Clear all items from the hashtable
Clone()	Returns a duplicate of the hashtable
Contains()	Returns True if a given object is in the current hashtable
ContainsKey()	Returns True if a given key is in the current hashtable
ContainsValue()	Returns True if a given value is in the current hashtable
CopyTo()	Copies all or part of the current hashtable to another hashtable that is passed in as an argument
Remove()	Removes a given item from the hashtable
Synchronized()	Synchronizes the hashtable

Hashtable.Count

Syntax

Int32 Count

Description

The Hashtable.Count property contains the total number of objects in the hashtable.

Example

Hashtable h = new Hashtable();
h.Add("key1", "value1");
h.Add("key2", "value2");
h.Add("key3", "value3");


MyLabel.Text = "Count is "+h.Count.ToString();

Hashtable.IsReadOnly

Syntax

Boolean IsReadOnly

Description

The Hashtable.IsReadOnly property enables a developer to check the read-only status of a hashtable.

Example

Hashtable h = new Hashtable();
h.Add("key1", "value1");
h.Add("key2", "value2");
h.Add("key3", "value3");


MyLabel.Text = "Is ReadOnly set to " + h.IsReadOnly;

Hashtable.IsSynchronized

Syntax

Boolean IsSynchronized

Description

The Hashtable.IsSynchronized property enables a developer to see if a given hashtable is synchronized.

Example

Hashtable h = new Hashtable();
h.Add("key1", "value1");
h.Add("key2", "value2");
h.Add("key3", "value3");

MyLabel.Text = "IsSynchronized set to " + h.IsSynchronized;

Hashtable.Item

Syntax

Object Item(Object key)

Description

The Hashtable.Item property enables a developer to access individual elements of a hashtable.

Example

Hashtable h = new Hashtable();
h.Add("key1", "value1");
h.Add("key2", "value2");
h.Add("key3", "value3");

MyLabel.Text = "Second item in hashtable: " + (string)h["key2"];

Hashtable.Keys

Syntax

ICollection Keys

Description

The Hashtable.Keys property contains a collection of all keys in a hashtable.

Example

Hashtable h = new Hashtable();
h.Add("key1", "value1");
h.Add("key2", "value2");
h.Add("key3", "value3");

MyList.DataSource = h.Keys;
MyList.DataBind();

Hashtable.Values

Syntax

ICollection Values

Description

The Hashtable.Values property contains a collection of all values in a hashtable.

Example

Hashtable h = new Hashtable();
h.Add("key1", "value1");
h.Add("key2", "value2");
h.Add("key3", "value3");

MyList.DataSource = h.Values;
MyList.DataBind();

Hashtable.Add()

Syntax

Viod Add(Object key, Object value)

Description

The Hashtable.Add() method adds name/value pairs to the hashtable.

Example

Hashtable h = new Hashtable();
h.Add("key1", "value1");
h.Add("key2", "value2");
h.Add("key3", "value3");

Hashtable.Clear()

Syntax

Void Clear()

Description

The Hashtable.Clear() method clears all keys and values from the hashtable.

Example

Hashtable h = new Hashtable();
h.Add("key1", "value1");
h.Add("key2", "value2");
h.Add("key3", "value3");

h.Clear();

Hashtable.Clone()

Syntax

Object Clone()

Description

The Hashtable.Clone() method creates an identical new hashtable.

Example

Hashtable h = new Hashtable();
h.Add("key1", "value1");
h.Add("key2", "value2");
h.Add("key3", "value3");

Hashtable h2 = (Hashtable)h.Clone();

Hashtable.Contains()

Syntax

Boolean Contains(Object key)

Description

The Hashtable.Contains() method enables a developer to check for the existence of a particular key in a hashtable.

Example

Hashtable h = new Hashtable();
h.Add("key1", "value1");
h.Add("key2", "value2");
h.Add("key3", "value3");

MyLabel.Text = "Does hashtable contain this key: " + h.Contains("key1").ToString();

Hashtable.ContainsKey()

Syntax

Boolean ContainsKey(Object key)

Description

The Hashtable.ContainsKey() method enables a developer to check for the existence of a particular key in a hashtable.

Example

Hashtable h = new Hashtable();
h.Add("key1", "value1");
h.Add("key2", "value2");
h.Add("key3", "value3");

MyLabel.Text = "Does hashtable contain this key: "+h.ContainsKey("key2").ToString();

Hashtable.ContainsValue()

Syntax

Boolean ContainsValue(Object value)

Description

The Hashtable.ContainsValue() method enables a developer to check for the existence of a particular value in a hashtable.

Example

Hashtable h = new Hashtable();
h.Add("key1", "value1");
h.Add("key2", "value2");
h.Add("key3", "value3");

MyLabel.Text = "Does hashtable contain this value: "+h.ContainsValue("value1").ToString();

Hashtable.CopyTo()

Syntax

Void CopyTo(Array array, Int32 arrayIndex)

Description

The Hashtable.CopyTo() method copies the hashtable to an array.

Example

Hashtable h = new Hashtable();
h.Add("key1", "value1");
h.Add("key2", "value2");
h.Add("key3", "value3");

String[] MyArray = new String[3];
h.CopyTo(MyArray, 0);
MyLabel.Text = "Third item of ArrayList is "+MyArray[2];

Hashtable.Remove()

Syntax

Void Remove( Object key )

Description

The Hashtable.Remove() method removes an entry from the hashtable by key.

Example

Hashtable h = new Hashtable();
h.Add("key1", "value1");
h.Add("key2", "value2");
h.Add("key3", "value3");

h.Remove("key3");

Hastable.Synchronized()

Syntax

Hashtable Synchronized( Hashtable table )

Description

The Hashtable.Synchronized() method returns a synchronized duplicate of the current hashtable.

Example

Hashtable h = new Hashtable();
h.Add("key1", "value1");
h.Add("key2", "value2");
h.Add("key3", "value3");

h = Hashtable.Synchronized(h);
MyLabel.Text = "True if items is synchronized: "+h.IsSynchronized;