# Owl's Blog on .NET development

Component Owl codes Better ListView control all night so you don't have to.

## Enabling Search Highlight in Better ListView

Blog Post by Libor Tinka published on Friday, 11 January 2013 in Better ListView, Components, Tutorials

We have improved item searching capabilities of Better ListView by introducing Search Highlight feature. This feature automatically shows search matches and works out of the box with both searching by typing and searching from code (e.g. using search box):

Search Highlight Feature

To enable the highlight, simply add UpdateSearchHighlight option in the search settings:

C#

[csharp gutter=”false” toolbar=”false”]
listView.SearchSettings = new BetterListViewSearchSettings(
listView.SearchSettings.Mode,
listView.SearchSettings.Options | BetterListViewSearchOptions.UpdateSearchHighlight,
listView.SearchSettings.SubItemIndices);
[/csharp]

Visual Basic

[vb gutter=”false” toolbar=”false”]
ListView.SearchSettings = New BetterListViewSearchSettings(
listView.SearchSettings.Mode,
listView.SearchSettings.Options Or BetterListViewSearchOptions.UpdateSearchHighlight,
listView.SearchSettings.SubItemIndices)
[/vb]

Every item contains information about the match in the BetterListViewItem.SearchHighlight property. When BetterListViewItem.SearchHighlight.IsEmpty is true, the item was not matched by the search. Otherwise it contains information about the matched substring: its index and number of characters.

Highlight colors can be adjusted by three properties: ColorSearchHighlight, ColorSearchHighlightBorder and ColorSearchHighlightText:

Search Highlight Properties

The display can be adjusted even further with owner drawing:

Customized Search Highlight Feature

Here we have used ellipses drawn on item background by modifying OnDrawItem and OnDrawItemBackground methods of BetterListView:

C#

[csharp gutter=”false” toolbar=”false”]
using System.Drawing;
using System.Drawing.Drawing2D;

using BetterListView;

internal sealed class CustomListView : BetterListView
{
protected override void OnDrawItem(BetterListViewDrawItemEventArgs eventArgs)
{
// do not draw search highlight because we will draw our own
eventArgs.DrawSearchHighlight = false;

base.OnDrawItem(eventArgs);
}

protected override void OnDrawItemBackground(BetterListViewDrawItemBackgroundEventArgs eventArgs)
{
base.OnDrawItemBackground(eventArgs);

// draw custom search highlight on item background
BetterListViewSearchHighlight searchHighlight = eventArgs.Item.SearchHighlight;

if (searchHighlight.IsEmpty == false)
{
eventArgs.Graphics.SmoothingMode = SmoothingMode.HighQuality;

Rectangle rectHighlight = eventArgs.ItemBounds.SubItemBounds[searchHighlight.ColumnIndex].BoundsSearchHighlight;

Brush brushHighlight = new SolidBrush(Color.FromArgb(128, Color.MediumPurple));
Pen penHighlight = new Pen(Color.Purple, 1.0f);

eventArgs.Graphics.FillEllipse(brushHighlight, rectHighlight);
eventArgs.Graphics.DrawEllipse(penHighlight, rectHighlight);

brushHighlight.Dispose();
penHighlight.Dispose();
}
}
}
[/csharp]

Visual Basic

[vb gutter=”false” toolbar=”false”]
Imports System.Drawing
Imports System.Drawing.Drawing2D

Imports BetterListView

Friend NotInheritable Class CustomListView
Inherits BetterListView
Protected Overrides Sub OnDrawItem(eventArgs As BetterListViewDrawItemEventArgs)
‘ do not draw search highlight because we will draw our own
eventArgs.DrawSearchHighlight = False

MyBase.OnDrawItem(eventArgs)
End Sub

Protected Overrides Sub OnDrawItemBackground(eventArgs As BetterListViewDrawItemBackgroundEventArgs)
MyBase.OnDrawItemBackground(eventArgs)

‘ draw custom search highlight on item background
Dim searchHighlight As BetterListViewSearchHighlight = eventArgs.Item.SearchHighlight

If searchHighlight.IsEmpty = False Then
eventArgs.Graphics.SmoothingMode = SmoothingMode.HighQuality

Dim rectHighlight As Rectangle = eventArgs.ItemBounds.SubItemBounds(searchHighlight.ColumnIndex).BoundsSearchHighlight

Dim brushHighlight As Brush = New SolidBrush(Color.FromArgb(128, Color.MediumPurple))
Dim penHighlight As New Pen(Color.Purple, 1F)

eventArgs.Graphics.FillEllipse(brushHighlight, rectHighlight)
eventArgs.Graphics.DrawEllipse(penHighlight, rectHighlight)

brushHighlight.Dispose()
penHighlight.Dispose()
End If
End Sub
End Class
[/vb]

Tags: better, better listview, highlight, highlighting, items, list, listview, mark, matched, search, searching

### One Response to “Enabling Search Highlight in Better ListView”

1. Camiel Hessels says:
   January 28, 2013 at 7:54 pm

   Awesome, just what I need! Thanks!

   Reply

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