MessageBox.Show Method (String)

May 11, 2014

Displays a message box that contains the specified text and an OK button.

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

'Declaration
Public Shared Function Show ( _
	messageBoxText As String _
) As MessageBoxResult

Parameters

messageBoxText
Type: System.String
The message to display.

Return Value

Type: System.Windows.MessageBoxResult
OK in all cases.

ExceptionCondition
ArgumentNullException

messageBoxText is Nothing.

Windows 8 Windows Phone 8: In Windows Phone 8 if you call Show(String) method from the app Activated or Launching event handlers an InvalidOperationException is thrown with the message Error Displaying MessageBox. Alternatively, you should call the Show method from the Page.OnNavigatedTo(NavigationEventArgs) method.

In addition, in Windows Phone 8, if you call Show in OnBackKeyPress(CancelEventArgs) or a handler for the BackKeyPress event, the app will exit. You can work around this by calling Show on a different thread described in the following steps.

  1. Override BackKeyPress or create a handler for the BackKeyPress event,

  2. Set the Cancel to true to cancel the back key press action

  3. Dispatch a method that shows the MessageBox

  4. If the user chooses to leave the app, call Terminate, otherwise do nothing.

The message box is modal, which means that the user must tap OK to dismiss the message.

The following example code demonstrates how to use this method.


MessageBox.Show("No caption, one button.")


Windows Phone OS

Supported in: 8.1, 8.0, 7.1, 7.0

Windows Phone

Show:
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