/Main/src/DynamicDataDisplay/DataSources/OneDimensional/EmptyDataSource.cs

 1using System;
 2using System.Collections.Generic;
 3using System.Linq;
 4using System.Text;
 5using System.Windows;
 6using System.Diagnostics.CodeAnalysis;
 7
 8namespace Microsoft.Research.DynamicDataDisplay.DataSources
 9{
10	/// <summary>
11	/// Empty data source - for testing purposes, represents data source with 0 points inside.
12	/// </summary>
13	public class EmptyDataSource : IPointDataSource
14	{
15		#region IPointDataSource Members
16
17		public IPointEnumerator GetEnumerator(DependencyObject context)
18		{
19			return new EmptyPointEnumerator();
20		}
21
22		[SuppressMessage("Microsoft.Performance", "CA1811:AvoidUncalledPrivateCode")]
23		private void RaiseDataChanged()
24		{
25			if (DataChanged != null)
26			{
27				DataChanged(this, EventArgs.Empty);
28			}
29		}
30
31		public event EventHandler DataChanged;
32
33		#endregion
34
35		private sealed class EmptyPointEnumerator : IPointEnumerator
36		{
37			public bool MoveNext()
38			{
39				return false;
40			}
41
42			public void GetCurrent(ref Point p)
43			{
44				// nothing to do
45			}
46
47			public void ApplyMappings(DependencyObject target)
48			{
49				// nothing to do
50			}
51
52			public void Dispose() { }
53		}
54	}
55}