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Building a thumbnail navigation index

Author:	TX Text Control Support Department
Language:	Visual Basic .NET
Version:	1.0
Released:	December 01, 2004
Last modified:	January 11, 2008
Requirements:	TX Text Control .NET with Visual Basic .NET
Download code:	tx_sample_dotnet_thumbs.zip [127.44 KB, ZIP]

How to build a document thumbnail navigation index

An interesting navigation feature to add to a word processor is that of thumbnail navigation -- create a thumbnail of every page in a document and display it on the left of the currently active document (as illustrated in the screenshot to the right).

In this sample application, you will learn how to create such navigation by using a small, zoomed TX Text Control. Every page of the current document is displayed on a separate TX Text Control that is added to a scrollable panel control.

First of all, we have to create a new TX Text Control for every page and copy the current page using the Load and Save methods into the small thumbnail TX Text Control. Consider the following code:

For pageCount = 1 To TextControl1.Pages
	Dim thumb As New TXTextControl.TextControl
	Dim dataBuffer() As Byte
 
	With thumb
		[...]
		TextControl1.Selection.Save(dataBuffer, TXTextControl.BinaryStreamType.InternalFormat)
		AddHandler .Click, AddressOf thumb_Click
		AddHandler .MouseHover, AddressOf thumb_Hover
		AddHandler .MouseLeave, AddressOf thumb_Leave
	End With
 
	Panel2.Controls.Add(thumb)
 
	If Not dataBuffer Is Nothing Then
		thumb.Load(dataBuffer, TXTextControl.BinaryStreamType.InternalFormat)
	End If
Next

Additionally, we add some event handlers for the thumbnails: a Click, a MouseHover and a MouseLeave event. The current page is stored in the Tag property of the current control, so that this value can be used to navigate to the specified page and to display the page number, if the user moves the mouse over the thumbnail.

Private Sub thumb_Click(ByVal sender As System.Object, ByVal e As System.EventArgs)
	Dim myThumb As New TXTextControl.TextControl
 
	For Each myThumb In Panel2.Controls
		myThumb.BackColor = System.Drawing.Color.White
	Next
 
	myThumb = sender
	myThumb.BackColor = System.Drawing.Color.Beige
	TextControl1.Focus()
	TextControl1.InputPosition = New TXTextControl.InputPosition(myThumb.Tag, 1, 0)
End Sub

The thumbs are updated, if a new page is inserted to the document. You can also force the update by pressing the 'Update...' button.

The minimum requirements for this sample application are TX Text Control .NET trial or TX Text Control .NET Enterprise retail version and Visual Studio .NET 2003.

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