Validating a textbox
Because the function depends on the modal dialog box to gather data, the modal dialog box also prevents a user from activating other windows in the application while it remains open.In most cases, a modal dialog box allows a user to signal when they have finished with the modal dialog box by pressing either an OK or Cancel button.Message Box lets you configure the message box text, title, icon, and buttons, using code like the following. User Page Range Enabled = true; // Show save file dialog box Nullable' Configure printer dialog box Dim dlg As New Print Dialog() dlg. As we'll see, a dialog box is a window with special behaviors.// Configure the message box to be displayed string message Box Text = "Do you want to save changes? Window implements those behaviors and, consequently, you use Window to create custom modal and modeless dialog boxes.
A is a dialog box that can be used to display textual information and to allow users to make decisions with buttons. For detailed discussion of printing in WPF, see Printing Overview.
The common open file dialog box is implemented as the Open File Dialog class and is located in the Microsoft. The following code shows how to create, configure, and show one, and how to process the result. A validation rule is a custom class that derives from Validation Rule. Controls Namespace SDKSample Public Class Margin Validation Rule Inherits Validation Rule Private _max Margin As Double Private _min Margin As Double Public Property Max Margin() As Double Get Return Me._max Margin End Get Set(By Val value As Double) Me._max Margin = value End Set End Property Public Property Min Margin() As Double Get Return Me._min Margin End Get Set(By Val value As Double) Me._min Margin = value End Set End Property Public Overrides Function Validate(By Val value As Object, By Val culture Info As Culture Info) As Validation Result Dim margin As Double ' Is a number? Try Parse(CStr(value), margin) Then Return New Validation Result(False, "Not a number.") End If ' Is in range? When a control contains invalid data, WPF will display a red border around the invalid control, as shown in the following figure.