This documentation is archived and is not being maintained.

MessageBox.Show Method (String, String, MessageBoxButtons, MessageBoxIcon, MessageBoxDefaultButton, MessageBoxOptions, String, HelpNavigator, Object)

Displays a message box with the specified text, caption, buttons, icon, default button, options, and Help button, using the specified Help file, HelpNavigator, and Help topic.

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

public static DialogResult Show(
	string text,
	string caption,
	MessageBoxButtons buttons,
	MessageBoxIcon icon,
	MessageBoxDefaultButton defaultButton,
	MessageBoxOptions options,
	string helpFilePath,
	HelpNavigator navigator,
	Object param


Type: System.String
The text to display in the message box.
Type: System.String
The text to display in the title bar of the message box.
Type: System.Windows.Forms.MessageBoxButtons
One of the MessageBoxButtons values that specifies which buttons to display in the message box.
Type: System.Windows.Forms.MessageBoxIcon
One of the MessageBoxIcon values that specifies which icon to display in the message box.
Type: System.Windows.Forms.MessageBoxDefaultButton
One of the MessageBoxDefaultButton values that specifies the default button for the message box.
Type: System.Windows.Forms.MessageBoxOptions
One of the MessageBoxOptions values that specifies which display and association options will be used for the message box. You may pass in 0 if you wish to use the defaults.
Type: System.String
The path and name of the Help file to display when the user clicks the Help button.
Type: System.Windows.Forms.HelpNavigator
One of the HelpNavigator values.
Type: System.Object
The numeric ID of the Help topic to display when the user clicks the Help button.

Return Value

Type: System.Windows.Forms.DialogResult
One of the DialogResult values.


buttons is not a member of MessageBoxButtons.


icon is not a member of MessageBoxIcon.


The defaultButton specified is not a member of MessageBoxDefaultButton.


An attempt was made to display the MessageBox in a process that is not running in User Interactive mode. This is specified by the SystemInformation.UserInteractive property.


options specified both DefaultDesktopOnly and ServiceNotification.


buttons specified an invalid combination of MessageBoxButtons.

A message box is a modal dialog box, which means no input (keyboard or mouse click) can occur except to objects on the modal form. The program must hide or close a modal form (typically in response to some user action) before input to another form can occur.

When the user clicks the Help button, the Help file specified in the helpFilePath parameter is opened and the Help content identified by the navigator parameter is displayed. The form that owns the message box (or the active form) also receives the HelpRequested event.

Compiled help files provide table of contents, index, search, and keyword links in pages. You can use the following values for navigator: TableOfContents, Find, Index, or Topic.

You can use param to provide further refinement of the Topic command. If the value specified in the navigator parameter is TableOfContents, Index, or Find, this value should be null. If the navigator parameter references Topic, this value should reference an object that contains the numeric value of the topic to display.

The helpFilePath parameter can be of the form C:\path\sample.chm or /folder/file.htm.

The following code example demonstrates how to show a message box with a Help button. When the user clicks the Help button, the Mspaint.chm Help file is opened and the Help index tab and the topic identified by the ovals keyword are displayed. The example requires that the Mspaint.chm Help file is installed.

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


            // Display a message box. The Help button opens the Mspaint.chm Help file, 
            // shows index with the "ovals" keyword selected, and displays the
            // associated topic.
            DialogResult r5 = MessageBox.Show ("Message with Help file and Help navigator with additional parameter.", 
                                               "Help Caption", MessageBoxButtons.OK, 
                                               0, "mspaint.chm", 
                                               HelpNavigator.KeywordIndex, "ovals");

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

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