MessageBox Class

Reference

Definition

Namespace:: System.Windows.Forms

Assembly:: System.Windows.Forms.dll

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

Displays a message window, also known as a dialog box, which presents a message to the user. It is a modal window, blocking other actions in the application until the user closes it. A MessageBox can contain text, buttons, and symbols that inform and instruct the user.

public ref class MessageBox

public class MessageBox

type MessageBox = class

Public Class MessageBox

Inheritance: Object
MessageBox

Examples

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 TextBox named ServerName on it.

private:
   void validateUserEntry()
   {
      // Checks the value of the text.
      if ( serverName->Text->Length == 0 )
      {
         // Initializes the variables to pass to the MessageBox::Show method.
         String^ message = "You did not enter a server name. Cancel this operation?";
         String^ caption = "No Server Name Specified";
         MessageBoxButtons buttons = MessageBoxButtons::YesNo;
         System::Windows::Forms::DialogResult result;

         // Displays the MessageBox.
         result = MessageBox::Show( this, message, caption, buttons );
         if ( result == ::DialogResult::Yes )
         {
            // Closes the parent form.
            this->Close();
         }
      }
   }

private void validateUserEntry()
{
    // Checks the value of the text.
    if(serverName.Text.Length == 0)
    {
        // Initializes the variables to pass to the MessageBox.Show method.
        string message = "You did not enter a server name. Cancel this operation?";
     string caption = "Error Detected in Input";
        MessageBoxButtons buttons = MessageBoxButtons.YesNo;
        DialogResult result;

        // Displays the MessageBox.
        result = MessageBox.Show(message, caption, buttons);
        if (result == System.Windows.Forms.DialogResult.Yes)
        {
            // Closes the parent form.
            this.Close();
        }
    }
}

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

The following code example shows how to ask the user a yes or no question and make a decision based on the response.

private:
   void Form1_FormClosing(Object^ sender, FormClosingEventArgs^ e)
   {
      // If the no button was pressed ...
      if ((MessageBox::Show(
         "Are you sure that you would like to close the form?", 
         "Form Closing", MessageBoxButtons::YesNo, 
         MessageBoxIcon::Question) == DialogResult::No))
      {
         // cancel the closure of the form.
         e->Cancel = true;
      }
   }

private void Form1_FormClosing(object sender, FormClosingEventArgs e)
{
    const string message =
        "Are you sure that you would like to close the form?";
    const string caption = "Form Closing";
    var result = MessageBox.Show(message, caption,
                                 MessageBoxButtons.YesNo,
                                 MessageBoxIcon.Question);

    // If the no button was pressed ...
    if (result == DialogResult.No)
    {
        // cancel the closure of the form.
        e.Cancel = true;
    }
}

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

Remarks

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.

Methods

Equals(Object)	Determines whether the specified object is equal to the current object. (Inherited from Object)
GetHashCode()	Serves as the default hash function. (Inherited from Object)
GetType()	Gets the Type of the current instance. (Inherited from Object)
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
Show(IWin32Window, String)	Displays a message box in front of the specified object and with the specified text.
Show(IWin32Window, String, String)	Displays a message box in front of the specified object and with the specified text and caption.
Show(IWin32Window, String, String, MessageBoxButtons)	Displays a message box in front of the specified object and with the specified text, caption, and buttons.
Show(IWin32Window, String, String, MessageBoxButtons, MessageBoxIcon)	Displays a message box in front of the specified object and with the specified text, caption, buttons, and icon.
Show(IWin32Window, String, String, MessageBoxButtons, MessageBoxIcon, MessageBoxDefaultButton)	Displays a message box in front of the specified object and with the specified text, caption, buttons, icon, and default button.
Show(IWin32Window, String, String, MessageBoxButtons, MessageBoxIcon, MessageBoxDefaultButton, MessageBoxOptions)	Displays a message box in front of the specified object and with the specified text, caption, buttons, icon, default button, and options.
Show(IWin32Window, String, String, MessageBoxButtons, MessageBoxIcon, MessageBoxDefaultButton, MessageBoxOptions, String)	Displays a message box with the specified text, caption, buttons, icon, default button, options, and Help button, using the specified Help file.
Show(IWin32Window, String, String, MessageBoxButtons, MessageBoxIcon, MessageBoxDefaultButton, MessageBoxOptions, String, HelpNavigator)	Displays a message box with the specified text, caption, buttons, icon, default button, options, and Help button, using the specified Help file and `HelpNavigator`.
Show(IWin32Window, 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.
Show(IWin32Window, String, String, MessageBoxButtons, MessageBoxIcon, MessageBoxDefaultButton, MessageBoxOptions, String, String)	Displays a message box with the specified text, caption, buttons, icon, default button, options, and Help button, using the specified Help file and Help keyword.
Show(String)	Displays a message box with specified text.
Show(String, String)	Displays a message box with specified text and caption.
Show(String, String, MessageBoxButtons)	Displays a message box with specified text, caption, and buttons.
Show(String, String, MessageBoxButtons, MessageBoxIcon)	Displays a message box with specified text, caption, buttons, and icon.
Show(String, String, MessageBoxButtons, MessageBoxIcon, MessageBoxDefaultButton)	Displays a message box with the specified text, caption, buttons, icon, and default button.
Show(String, String, MessageBoxButtons, MessageBoxIcon, MessageBoxDefaultButton, MessageBoxOptions)	Displays a message box with the specified text, caption, buttons, icon, default button, and options.
Show(String, String, MessageBoxButtons, MessageBoxIcon, MessageBoxDefaultButton, MessageBoxOptions, Boolean)	Displays a message box with the specified text, caption, buttons, icon, default button, options, and Help button.
Show(String, String, MessageBoxButtons, MessageBoxIcon, MessageBoxDefaultButton, MessageBoxOptions, String)	Displays a message box with the specified text, caption, buttons, icon, default button, options, and Help button, using the specified Help file.
Show(String, String, MessageBoxButtons, MessageBoxIcon, MessageBoxDefaultButton, MessageBoxOptions, String, HelpNavigator)	Displays a message box with the specified text, caption, buttons, icon, default button, options, and Help button, using the specified Help file and `HelpNavigator`.
Show(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.
Show(String, String, MessageBoxButtons, MessageBoxIcon, MessageBoxDefaultButton, MessageBoxOptions, String, String)	Displays a message box with the specified text, caption, buttons, icon, default button, options, and Help button, using the specified Help file and Help keyword.
ToString()	Returns a string that represents the current object. (Inherited from Object)

Applies to

Compartir vía