MessageBox Class

Definition

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

Applies to

See also

• Show(String, String, MessageBoxButtons, MessageBoxIcon, MessageBoxDefaultButton, MessageBoxOptions, Boolean)