MessageBox Class
Displays a message box that can contain text, buttons, and symbols that inform and instruct the user.
Assembly: System.Windows.Forms (in System.Windows.Forms.dll)
You cannot create a new instance of the MessageBox class. To display a message box, call the static method MessageBox.Show. The title, message, buttons, and icons displayed in the message box are determined by parameters that you pass to this method.
The following code example shows how to use a MessageBox to inform the user of a missing entry in a TextBox. This example requires that the method is called from an existing form with a Button and a TextBox on it.
Private Sub Form1_FormClosing( _ ByVal sender As System.Object, _ ByVal e As System.Windows.Forms.FormClosingEventArgs) _ Handles MyBase.FormClosing Dim message As String = _ "Are you sure that you would like to close the form?" Dim caption As String = "Form Closing" Dim result = MessageBox.Show(message, caption, _ MessageBoxButtons.YesNo, _ MessageBoxIcon.Question) ' If the no button was pressed ... If (result = DialogResult.No) Then ' cancel the closure of the form. e.Cancel = True End If End Sub
The following code example shows how to ask the user a yes or no question and make a decision based on the response.
Private Sub ValidateUserEntry() ' Checks the value of the text. If ServerName.Text.Length = 0 Then ' Initializes variables to pass to the MessageBox.Show method. Dim Message As String = "You did not enter a server name. Cancel this operation?" Dim Caption As String = "Error Detected in Input" Dim Buttons As MessageBoxButtons = MessageBoxButtons.YesNo Dim Result As DialogResult 'Displays the MessageBox Result = MessageBox.Show(Message, Caption, Buttons) ' Gets the result of the MessageBox display. If Result = System.Windows.Forms.DialogResult.Yes Then ' Closes the parent form. Me.Close() End If End If End Sub
Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.