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HelpNavigator Enumeration
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HelpNavigator Enumeration

Specifies constants indicating which elements of the Help file to display.

Namespace:  System.Windows.Forms
Assembly:  System.Windows.Forms (in System.Windows.Forms.dll)

'Declaration
Public Enumeration HelpNavigator

Member nameDescription
AssociateIndexThe Help file opens to the index entry for the first letter of a specified topic.
FindThe Help file opens to the search page.
IndexThe Help file opens to the index.
KeywordIndexThe Help file opens to the topic with the specified index entry, if one exists; otherwise, the index entry closest to the specified keyword is displayed.
TableOfContentsThe Help file opens to the table of contents.
TopicThe Help file opens to a specified topic, if the topic exists.
TopicIdThe Help file opens to a topic indicated by a numeric topic identifier.

This enumeration is used by the Help and HelpProvider classes to provide access to specific elements of a Help file. For example, when used with the HelpProvider component that provides F1 Help, the TopicId or Topic value could be specified to open Help to a context-specific topic.

The following code example displays a form with three buttons that can be used to interact with the mspaint.chm Help file. The Show Help Index button displays the Index tab for the Help file. The Show Help button displays content in the Help file based on the value selected in the Help Navigator list. The Show Keyword button displays content in the Help file based on the keyword specified in the Keyword text box.

For example, to show the Ovals Help page by the index value, select the HelpNavigator.KeywordIndex value in the Help Navigator drop-down list, type ovals in the Parameter text box, and then click the Show Help button. To show the "To paint with a brush" Help topic by the keyword, type mspaint.chm::/paint_brush.htm in the Keyword text box, and then click the Show Keyword button.

The example uses the ShowHelp method to display the different Help tabs and Help topics, and the ShowHelpIndex method to display the Help index.

Imports System
Imports System.Drawing
Imports System.ComponentModel
Imports System.Windows.Forms

Public Class Form1
    Inherits System.Windows.Forms.Form
    Private helpfile As String = "mspaint.chm" 
    Private WithEvents showIndex As System.Windows.Forms.Button
    Private WithEvents showHelp As System.Windows.Forms.Button
    Private WithEvents label1 As System.Windows.Forms.Label
    Private WithEvents navigatorCombo As System.Windows.Forms.ComboBox
    Private WithEvents showKeyword As System.Windows.Forms.Button
    Private WithEvents keyword As System.Windows.Forms.TextBox
    Private WithEvents label2 As System.Windows.Forms.Label
    Private WithEvents label3 As System.Windows.Forms.Label
    Private WithEvents parameterTextBox As System.Windows.Forms.TextBox

    <STAThread()> _
    Shared Sub Main()
        Application.Run(New Form1)
    End Sub 'Main

    Public Sub New()
        Me.showIndex = New System.Windows.Forms.Button
        Me.showHelp = New System.Windows.Forms.Button
        Me.navigatorCombo = New System.Windows.Forms.ComboBox
        Me.label1 = New System.Windows.Forms.Label
        Me.showKeyword = New System.Windows.Forms.Button
        Me.keyword = New System.Windows.Forms.TextBox
        Me.label2 = New System.Windows.Forms.Label
        Me.label3 = New System.Windows.Forms.Label
        Me.parameterTextBox = New System.Windows.Forms.TextBox

        ' Help Navigator Label 
        Me.label1.Location = New System.Drawing.Point(112, 64)
        Me.label1.Size = New System.Drawing.Size(168, 16)
        Me.label1.Text = "Help Navigator:" 

        ' Keyword Label 
        Me.label2.Location = New System.Drawing.Point(120, 184)
        Me.label2.Size = New System.Drawing.Size(100, 16)
        Me.label2.Text = "Keyword:" 

        ' Parameter Label 
        Me.label3.Location = New System.Drawing.Point(112, 120)
        Me.label3.Size = New System.Drawing.Size(168, 16)
        Me.label3.Text = "Parameter:" 

        ' Show Index Button 
        Me.showIndex.Location = New System.Drawing.Point(16, 16)
        Me.showIndex.Size = New System.Drawing.Size(264, 32)
        Me.showIndex.TabIndex = 0
        Me.showIndex.Text = "Show Help Index" 

        ' Show Help Button 
        Me.showHelp.Location = New System.Drawing.Point(16, 80)
        Me.showHelp.Size = New System.Drawing.Size(80, 80)
        Me.showHelp.TabIndex = 1
        Me.showHelp.Text = "Show Help" 

        ' Show Keyword Button 
        Me.showKeyword.Location = New System.Drawing.Point(16, 192)
        Me.showKeyword.Size = New System.Drawing.Size(88, 32)
        Me.showKeyword.TabIndex = 4
        Me.showKeyword.Text = "Show Keyword" 

        ' Help Navigator Combo 
        '  
        Me.navigatorCombo.DropDownStyle = System.Windows.Forms.ComboBoxStyle.DropDownList
        Me.navigatorCombo.Location = New System.Drawing.Point(112, 80)
        Me.navigatorCombo.Size = New System.Drawing.Size(168, 21)
        Me.navigatorCombo.TabIndex = 2

        ' Keyword TextBox 
        Me.keyword.Location = New System.Drawing.Point(120, 200)
        Me.keyword.Size = New System.Drawing.Size(160, 20)
        Me.keyword.TabIndex = 5
        Me.keyword.Text = "" 
        '  
        ' Parameter TextBox 
        '  
        Me.parameterTextBox.Location = New System.Drawing.Point(112, 136)
        Me.parameterTextBox.Size = New System.Drawing.Size(168, 20)
        Me.parameterTextBox.TabIndex = 8
        Me.parameterTextBox.Text = "" 

        ' Set up how the form should be displayed and add the controls to the form. 
        Me.ClientSize = New System.Drawing.Size(292, 266)
        Me.Controls.AddRange(New System.Windows.Forms.Control() {Me.parameterTextBox, _
                                Me.label3, Me.label2, Me.keyword, Me.showKeyword, _
                                Me.label1, Me.navigatorCombo, Me.showHelp, Me.showIndex})
        Me.FormBorderStyle = System.Windows.Forms.FormBorderStyle.FixedDialog
        Me.Text = "Help App" 

        ' Load the various values of the HelpNavigator enumeration 
        ' into the combo box.  
        Dim converter As TypeConverter
        converter = TypeDescriptor.GetConverter(GetType(HelpNavigator))

        Dim value As Object 
        For Each value In converter.GetStandardValues()
            navigatorCombo.Items.Add(value)
        Next value
    End Sub 'New 

    Private Sub showIndex_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles showIndex.Click
        ' Display the index for the Help file.
        Help.ShowHelpIndex(Me, helpfile)
    End Sub 'showIndex_Click
    Private Sub showHelp_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles showHelp.Click
        ' Display Help using the Help navigator enumeration 
        ' that is selected in the combo box. Some enumeration 
        ' values make use of an extra parameter, which can 
        ' be passed in through the Parameter text box. 
        Dim navigator As HelpNavigator = HelpNavigator.TableOfContents
        If (navigatorCombo.SelectedItem IsNot Nothing) Then
            navigator = CType(navigatorCombo.SelectedItem, HelpNavigator)
        End If
        Help.ShowHelp(Me, helpfile, navigator, parameterTextBox.Text)
    End Sub 'showHelp_Click
    Private Sub showKeyword_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles showKeyword.Click
        ' Display Help using the provided keyword. 
        Help.ShowHelp(Me, helpfile, keyword.Text)
    End Sub 'showKeyword_Click
End Class 'Form1

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1

.NET Framework Client Profile

Supported in: 4, 3.5 SP1
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