MessageBox Class
Important
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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
-
MessageBox
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
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.
Equals(Object) |
Determines whether the specified object is equal to the current object. (Inherited from Object) |
Get |
Serves as the default hash function. (Inherited from Object) |
Get |
Gets the Type of the current instance. (Inherited from Object) |
Memberwise |
Creates a shallow copy of the current Object. (Inherited from Object) |
Show(IWin32Window, String, String, Message |
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, Message |
Displays a message box with the specified text, caption, buttons, icon, default button, options, and Help button, using the specified Help file and |
Show(IWin32Window, String, String, Message |
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(IWin32Window, String, String, Message |
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, Message |
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, Message |
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, Message |
Displays a message box in front of the specified object and with the specified text, caption, buttons, and icon. |
Show(IWin32Window, String, String, Message |
Displays a message box in front of the specified object and with the specified text, caption, and buttons. |
Show(IWin32Window, String, String) |
Displays a message box in front of the specified object and with the specified text and caption. |
Show(IWin32Window, String) |
Displays a message box in front of the specified object and with the specified text. |
Show(String, String, Message |
Displays a message box with the specified text, caption, buttons, icon, default button, options, and Help button. |
Show(String, String, Message |
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, Message |
Displays a message box with the specified text, caption, buttons, icon, default button, options, and Help button, using the specified Help file and |
Show(String, String, Message |
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, String, Message |
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, Message |
Displays a message box with the specified text, caption, buttons, icon, default button, and options. |
Show(String, String, Message |
Displays a message box with the specified text, caption, buttons, icon, and default button. |
Show(String, String, Message |
Displays a message box with specified text, caption, buttons, and icon. |
Show(String, String, Message |
Displays a message box with specified text, caption, and buttons. |
Show(String, String) |
Displays a message box with specified text and caption. |
Show(String) |
Displays a message box with specified text. |
To |
Returns a string that represents the current object. (Inherited from Object) |
Produit | Versions |
---|---|
.NET Framework | 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1 |
Windows Desktop | 3.0, 3.1, 5, 6, 7, 8, 9 |
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