// ************************* methods *****************************************
/// <summary>
/// Add an item to the end of the table with the given key value.
/// </summary>
/// <param name="key">
/// The key value of the item. An ArgumentNullException exception is raised if
/// key is null. An ArgumentException exception is raised if the key already
/// exists in the collection.
/// </param>
/// <param name="item">The item being added to the table.</param>
public void Add(string key, object item)
{
// add value to Values list
Values.Add(key, item);
// add key to list of keys
KeysByIndex.Add(key);
}
/// <summary>
/// Sort the list by the key values. This affects the order returned
/// by integer index values and the enumerator.
/// </summary>
public void SortKeys()
{
// only do this if there are two or more items in the list
if (Values.Count > 1)
{
KeysByIndex.Sort();
}
}
/// <summary>
/// Insert an item into the table at a given position. A unique key value
/// is automatically created for the item. This key value will take the form
/// "cIndexedHashTable_Key_XXXX" (where XXXX is a number from 1 to 2^63).
/// </summary>
/// <param name="position">
/// The position of the item in the table (0 based). An ArgumentOutOfRangeException
/// exception is raised if position is less than zero or greater than the number of
/// items in the list minus one.
/// </param>
/// <param name="item">The item being added to the table.</param>
public void Insert(int position, object item)
{
// get a key for the new item
// this must be unique and is generated by the AddNum private variable
StringBuilder key = new StringBuilder("cIndexedHashTable_Key_");
key.Append(AddNum++);
// add key to list of keys. Do this first in case it causes an exception.
KeysByIndex.Insert(position, key.ToString());
// add value to Values list
Values.Add(key, item);
}
/// <summary>
/// Returns the position of the passed item in the table. NOTE: this
/// function is relatively inefficient and should not be called repeatedly.
/// </summary>
/// <param name="item">The item to search for.</param>
/// <returns>
/// The position of the item in the table. -1 is returned if the item is
/// not found.
/// </returns>
public int IndexOf(object item)
{
foreach (DictionaryEntry DE in Values)
{
// is this the value we are looking for
if (item == DE.Value)
{
// YES: return the position of it's key
return(KeysByIndex.IndexOf((string)DE.Key));
}
}
return(-1);
}
/// <summary>
/// Remove the item from the table at the given index position.
/// </summary>
/// <param name="index">
/// The index position of the item to remove. An ArgumentOutOfRangeException
/// exception is raised if index is less than zero or greater than the number
/// of items in the list minus one.
/// </param>
public void RemoveAt(int index)
{
// make sure Index is in range
if (index < 0 || index >= Values.Count)
{
throw new ArgumentOutOfRangeException("index");
}
// remove the value at this position
object key = KeysByIndex[index];
KeysByIndex.RemoveAt(index);
Values.Remove(key);
}
/// <summary>
/// Insert an item into the table at a given position.
/// </summary>
/// <param name="position">
/// The position of the item in the table (0 based). An ArgumentOutOfRangeException
/// exception is raised if position is less than zero or greater than the number of
/// items in the list minus one.
/// </param>
/// <param name="key">
/// The key value of the item. An ArgumentNullException exception is raised if
/// key is null. An ArgumentException exception is raised if the key already
/// exists in the collection.
/// </param>
/// <param name="item">The item being added to the table.</param>
public void Insert(int position, string key, object item)
{
// add key to list of keys. Do this first in case it causes an exception.
KeysByIndex.Insert(position, key);
// add value to Values list
try
{
Values.Add(key, item);
}
catch (Exception)
{
// if an error occurs here, remove the key value from the KeysByIndex list
// and rethrow the exception.
KeysByIndex.RemoveAt(position);
throw;
}
}
/// <summary>
/// Remove the item from the table with the given key value.
/// </summary>
/// <param name="key">
/// The key value of the item to remove. An ArgumentNullException exception is
/// raised if key is null.
/// </param>
public void Remove(string key)
{
Values.Remove(key);
KeysByIndex.Remove(key);
}
/// <summary>
/// Remove all items from the table.
/// </summary>
public void Clear()
{
// clear Values hashtable and list of keys
Values.Clear();
KeysByIndex.Clear();
}