Properties and Methods of the Hashtable Class
| 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;
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