HelpProvider Class

Provides pop-up or online Help for controls.

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

public class HelpProvider : Component, 
	IExtenderProvider

The HelpProvider type exposes the following members.

  NameDescription
Public methodHelpProviderInitializes a new instance of the HelpProvider class.
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  NameDescription
Protected propertyCanRaiseEventsGets a value indicating whether the component can raise an event. (Inherited from Component.)
Public propertyContainerGets the IContainer that contains the Component. (Inherited from Component.)
Protected propertyDesignModeGets a value that indicates whether the Component is currently in design mode. (Inherited from Component.)
Protected propertyEventsGets the list of event handlers that are attached to this Component. (Inherited from Component.)
Public propertyHelpNamespaceGets or sets a value specifying the name of the Help file associated with this HelpProvider object.
Public propertySiteGets or sets the ISite of the Component. (Inherited from Component.)
Public propertyTagGets or sets the object that contains supplemental data about the HelpProvider.
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  NameDescription
Public methodCanExtendSpecifies whether this object can provide its extender properties to the specified object.
Public methodCreateObjRefCreates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object. (Inherited from MarshalByRefObject.)
Public methodDispose()Releases all resources used by the Component. (Inherited from Component.)
Protected methodDispose(Boolean)Releases the unmanaged resources used by the Component and optionally releases the managed resources. (Inherited from Component.)
Public methodEquals(Object)Determines whether the specified object is equal to the current object. (Inherited from Object.)
Protected methodFinalizeReleases unmanaged resources and performs other cleanup operations before the Component is reclaimed by garbage collection. (Inherited from Component.)
Public methodGetHashCodeServes as the default hash function. (Inherited from Object.)
Public methodGetHelpKeywordReturns the Help keyword for the specified control.
Public methodGetHelpNavigatorReturns the current HelpNavigator setting for the specified control.
Public methodGetHelpStringReturns the contents of the pop-up Help window for the specified control.
Public methodGetLifetimeServiceRetrieves the current lifetime service object that controls the lifetime policy for this instance. (Inherited from MarshalByRefObject.)
Protected methodGetServiceReturns an object that represents a service provided by the Component or by its Container. (Inherited from Component.)
Public methodGetShowHelpReturns a value indicating whether the specified control's Help should be displayed.
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodInitializeLifetimeServiceObtains a lifetime service object to control the lifetime policy for this instance. (Inherited from MarshalByRefObject.)
Protected methodMemberwiseClone()Creates a shallow copy of the current Object. (Inherited from Object.)
Protected methodMemberwiseClone(Boolean)Creates a shallow copy of the current MarshalByRefObject object. (Inherited from MarshalByRefObject.)
Public methodResetShowHelpInfrastructure. Removes the Help associated with the specified control.
Public methodSetHelpKeywordSpecifies the keyword used to retrieve Help when the user invokes Help for the specified control.
Public methodSetHelpNavigatorSpecifies the Help command to use when retrieving Help from the Help file for the specified control.
Public methodSetHelpStringSpecifies the Help string associated with the specified control.
Public methodSetShowHelpSpecifies whether Help is displayed for the specified control.
Public methodToStringInfrastructure. Returns a string that represents the current HelpProvider. (Overrides Component.ToString().)
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  NameDescription
Public eventDisposedOccurs when the component is disposed by a call to the Dispose method. (Inherited from Component.)
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Each instance of HelpProvider maintains a collection of references to controls associated with it. To associate a Help file with the HelpProvider, set the HelpNamespace property. You specify the type of Help provided by calling the SetHelpNavigator method and providing a HelpNavigator value for the specified control. You provide the keyword or topic for the Help by calling the SetHelpKeyword method. To open Help to a specific topic, the keyword should be passed in the form topicName.htm.

To associate a specific Help string with a control, use the SetHelpString method. The string that you associate with a control using this method is displayed in a pop-up window when the user presses the F1 key while the control has focus.

If the HelpNamespace property has not been set, you must use the SetHelpString method to provide the Help text. If you have set both HelpNamespace and the Help string, Help based on the HelpNamespace will take precedence.

HelpProvider calls methods on the Help class to provide Help functionality.

The following code example demonstrates using the HelpProvider class to display context-sensitive Help on a form containing four address fields. The example uses the SetHelpString method to set the Help ToolTip text. When you use the context-sensitive Help button and click the Help cursor on an address field, the Help ToolTip appears with the specified text. When you press the F1 key with the focus in an address field, the mspaint.chm Help file is displayed because the HelpNamespace property has been set to mspaint.chm. The SetShowHelp method is called for each address control to identify that it has Help content available.

using System;
using System.Drawing;
using System.Windows.Forms;

public class Form1 : System.Windows.Forms.Form
{
	private System.Windows.Forms.TextBox addressTextBox;
	private System.Windows.Forms.Label label2;
	private System.Windows.Forms.TextBox cityTextBox;
	private System.Windows.Forms.Label label3;
	private System.Windows.Forms.TextBox stateTextBox;
	private System.Windows.Forms.TextBox zipTextBox;
	private System.Windows.Forms.HelpProvider helpProvider1;
	private System.Windows.Forms.Label helpLabel;

    [STAThread]
    static void Main() 
    {
        Application.Run(new Form1());
    }

	public Form1()
	{
        this.addressTextBox = new System.Windows.Forms.TextBox();
        this.helpLabel = new System.Windows.Forms.Label();
        this.label2 = new System.Windows.Forms.Label();
        this.cityTextBox = new System.Windows.Forms.TextBox();
        this.label3 = new System.Windows.Forms.Label();
        this.stateTextBox = new System.Windows.Forms.TextBox();
        this.zipTextBox = new System.Windows.Forms.TextBox();

        // Help Label 
        this.helpLabel.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D;
        this.helpLabel.Location = new System.Drawing.Point(8, 80);
        this.helpLabel.Size = new System.Drawing.Size(272, 72);
        this.helpLabel.Text = "Click the Help button in the title bar, then click a control " + 
            "to see a Help tooltip for the control.  Click on a control and press F1 to invoke " +
            "the Help system with a sample Help file.";

        // Address Label 
        this.label2.Location = new System.Drawing.Point(16, 8);
        this.label2.Size = new System.Drawing.Size(100, 16);
        this.label2.Text = "Address:";

        // Comma Label 
        this.label3.Location = new System.Drawing.Point(136, 56);
        this.label3.Size = new System.Drawing.Size(16, 16);
        this.label3.Text = ",";

        // Create the HelpProvider. 
        this.helpProvider1 = new System.Windows.Forms.HelpProvider();

        // Tell the HelpProvider what controls to provide help for, and 
        // what the help string is. 
        this.helpProvider1.SetShowHelp(this.addressTextBox, true);
        this.helpProvider1.SetHelpString(this.addressTextBox, "Enter the street address in this text box.");

        this.helpProvider1.SetShowHelp(this.cityTextBox, true);
        this.helpProvider1.SetHelpString(this.cityTextBox, "Enter the city here.");

        this.helpProvider1.SetShowHelp(this.stateTextBox, true);
        this.helpProvider1.SetHelpString(this.stateTextBox, "Enter the state in this text box.");

        this.helpProvider1.SetShowHelp(this.zipTextBox, true);
        this.helpProvider1.SetHelpString(this.zipTextBox, "Enter the zip code here.");

        // Set what the Help file will be for the HelpProvider. 
        this.helpProvider1.HelpNamespace = "mspaint.chm";

        // Sets properties for the different address fields. 

        // Address TextBox 
        this.addressTextBox.Location = new System.Drawing.Point(16, 24);
        this.addressTextBox.Size = new System.Drawing.Size(264, 20);
        this.addressTextBox.TabIndex = 0;
        this.addressTextBox.Text = "";

        // City TextBox 
        this.cityTextBox.Location = new System.Drawing.Point(16, 48);
        this.cityTextBox.Size = new System.Drawing.Size(120, 20);
        this.cityTextBox.TabIndex = 3;
        this.cityTextBox.Text = "";

        // State TextBox 
        this.stateTextBox.Location = new System.Drawing.Point(152, 48);
        this.stateTextBox.MaxLength = 2;
        this.stateTextBox.Size = new System.Drawing.Size(32, 20);
        this.stateTextBox.TabIndex = 5;
        this.stateTextBox.Text = "";

        // Zip TextBox 
        this.zipTextBox.Location = new System.Drawing.Point(192, 48);
        this.zipTextBox.Size = new System.Drawing.Size(88, 20);
        this.zipTextBox.TabIndex = 6;
        this.zipTextBox.Text = "";

        // Add the controls to the form. 
        this.Controls.AddRange(new System.Windows.Forms.Control[] {
                                    this.zipTextBox, this.stateTextBox,
                                    this.label3, this.cityTextBox,
                                    this.label2, this.helpLabel,
                                    this.addressTextBox});

        // Set the form to look like a dialog, and show the HelpButton.     
        this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.FixedDialog;
        this.HelpButton = true;
        this.MaximizeBox = false;
        this.MinimizeBox = false;
        this.ClientSize = new System.Drawing.Size(292, 160);
        this.Text = "Help Provider Demonstration";

    }
}

.NET Framework

Supported in: 4.5.3, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
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