A non-trivial application may also display additional windows to do the following: dialog box is displayed by a function when the function needs additional data from a user to continue.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.
Since finding a word doesn't prevent a user from editing the document, however, the dialog box doesn't need to be modal.A modeless dialog box at least provides a Close button to close the dialog box, and may provide additional buttons to execute specific functions, such as a Find Next button to find the next word that matches the find criteria of a word search.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 following figure shows a message box that displays textual information, asks a question, and provides the user with three buttons to answer the question. While common dialog boxes are useful, and should be used when possible, they do not support the requirements of domain-specific dialog boxes.However, this means a user can enter invalid data and press the OK button.
For this reason, your code also needs to validate all controls in a dialog box when the OK button is pressed by handling the Click event.A dialog box, on the other hand, does not prevent a user from activating other windows while it is open.For example, if a user wants to find occurrences of a particular word in a document, a main window will often open a dialog box to ask a user what word they are looking for.Warning ' Display message box Dim result As Message Box Result = Message Box. For these, Windows Presentation Foundation (WPF) provides several common dialog boxes and allows you to create your own dialog boxes, although the use of either is limited to applications running with full trust. Default Ext = ".txt"; // Default file extension dlg. File Name = "Document" ' Default file name dlg. Filter = "Text documents (.txt)|*.txt"; // Filter files by extension // Show save file dialog box Nullable' Configure save file dialog box Dim dlg As New Microsoft. Default Ext = ".text" ' Default file extension dlg. The entire process of instantiating, configuring, and opening a dialog box is shown in the following code.Show(message Box Text, caption, button, icon) ' Process message box results Select Case result Case Message Box Result. Windows implements a variety of reusable dialog boxes that are common to all applications, including dialog boxes for opening files, saving files, and printing. Filter = "Text documents (.txt)|*.txt"; // Filter files by extension // Show open file dialog box Nullable' Configure open file dialog box Dim dlg As New Microsoft. Default Ext = ".txt" ' Default file extension dlg. Filter = "Text documents (.txt)|*.txt" ' Filter files by extension ' Show save file dialog box Dim result? Show Dialog() ' Process save file dialog box results If result = True Then ' Save document Dim filename As String = dlg. The print dialog box, shown in the following figure, is used by printing functionality to choose and configure the printer that a user would like to print data to. The following code shows how to create, configure, and show one. Here, the code is passing default information (the current margins) to the dialog box. Owner property with a reference to the window that is showing the dialog box.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.