MessageBoxDefaultButton 枚举

指定若干常数，用以定义 MessageBox 上的默认按钮。

**命名空间:**System.Windows.Forms
**程序集:**System.Windows.Forms（在 system.windows.forms.dll 中）

语法

声明
Public Enumeration MessageBoxDefaultButton
用法
Dim instance As MessageBoxDefaultButton

public enum MessageBoxDefaultButton

public enum class MessageBoxDefaultButton

public enum MessageBoxDefaultButton

public enum MessageBoxDefaultButton

成员

	成员名称	说明
	Button1	消息框上的第一个按钮是默认按钮。
	Button2	消息框上的第二个按钮是默认按钮。
	Button3	消息框上的第三个按钮是默认按钮。

备注

此枚举由 MessageBox 类使用。

示例

Private Sub ValidateUserEntry2()


    ' 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 = "No Server Name Specified"
        Dim Buttons As Integer = MessageBoxButtons.YesNo

        Dim Result As DialogResult

        'Displays a MessageBox using the Question icon and specifying the No button as the default.

        Result = MessageBox.Show(Me, Message, Caption, MessageBoxButtons.YesNo, _
            MessageBoxIcon.Question, MessageBoxDefaultButton.Button1, MessageBoxOptions.RightAlign)


        ' Gets the result of the MessageBox display.

        If Result = DialogResult.Yes Then

            ' Closes the parent form.

            Me.Close()

        End If

    End If

End Sub

private void validateUserEntry2()
{

    // 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;
        DialogResult result;

        // Displays the MessageBox.

        result = MessageBox.Show(this, message, caption, buttons,
            MessageBoxIcon.Question, MessageBoxDefaultButton.Button1, 
            MessageBoxOptions.RightAlign);

        if(result == DialogResult.Yes)
        {

            // Closes the parent form.

            this.Close();

        }

    }

}

private:
   void validateUserEntry2()
   {
      // 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, MessageBoxIcon::Question, MessageBoxDefaultButton::Button1, MessageBoxOptions::RightAlign );
         if ( result == ::DialogResult::Yes )
         {
            // Closes the parent form.
            this->Close();
         }
      }
   }

private void ValidateUserEntry2()
{
    // Checks the value of the text.
    if (serverName.get_Text().get_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;
        DialogResult result;

        // Displays the MessageBox.
        result = MessageBox.Show(this, message, caption, buttons, 
            MessageBoxIcon.Question, MessageBoxDefaultButton.Button1, 
            MessageBoxOptions.RightAlign);

        if (result.Equals(DialogResult.Yes)) {
            // Closes the parent form.
            this.Close();
        }
    }
} //ValidateUserEntry2

平台

Windows 98、Windows 2000 SP4、Windows CE、Windows Millennium Edition、Windows Mobile for Pocket PC、Windows Mobile for Smartphone、Windows Server 2003、Windows XP Media Center Edition、Windows XP Professional x64 Edition、Windows XP SP2、Windows XP Starter Edition

.NET Framework 并不是对每个平台的所有版本都提供支持。有关受支持版本的列表，请参见系统要求。

版本信息

.NET Framework

受以下版本支持：2.0、1.1、1.0

.NET Compact Framework

受以下版本支持：2.0、1.0

请参见

参考

System.Windows.Forms 命名空间