Relationships Between Forms Windows Forms I: Developing Desktop Applications
4.3 Relationships Between Forms
The Form class has two properties that control a forms relationship to other forms: the Parent property inherited from the Control class and the Owner property. Setting the Parent property causes the constrained form to appear only within the bounds of the parent—and always to appear on top of the parent. This gives an effect similar to MDI applications which have other features as well and are discussed later in this chapter. When a form has a parent, it can be docked to the parents edges, just like any other control. The code in Ex am ple 4- 4 demonstrates this. It can be compiled from the command line with this command: vbc filename.vb r:System.dll,System.Drawing.dll,System.Windows.Forms.dll t:winexe The result is displayed in Figur e 4- 6 . 146 Figure 4-6. A form with a parent Example 4-4. Creating a form with a parent Imports System.Drawing Imports System.Windows.Forms Module modMain System.STAThreadAttribute Public Sub Main System.Threading.Thread.CurrentThread.ApartmentState = _ System.Threading.ApartmentState.STA System.Windows.Forms.Application.RunNew MyParentForm End Sub End Module Public Class MyParentForm Inherits Form Public Sub New Set my size. Me.ClientSize = New System.Drawing.Size600, 400 Create and show a child form. Dim frm As New MyChildFormMe frm.Show End Sub End Class Public Class MyChildForm Inherits Form Public Sub NewByVal Parent As Control TopLevel must be False for me to have a parent. Me.TopLevel = False Set my parent. Me.Parent = Parent Dock to my parents left edge. Me.Dock = DockStyle.Left End Sub End Class If the child form is maximized, it expands to fill the parent form. If the child form is minimized, it shrinks to a small rectangle at the bottom of the parent window. Because the child form in this example has a title bar and a sizable border, it can be moved and sized even though it has been docked. This behavior can be changed by modifying the forms FormBorderStyle property. 147 Setting the Owner property of a form causes another form to own the first. An owned form is not constrained to appear within the bounds of its owner, but when it does overlay its owner, it is always on top. Furthermore, the owned form is always minimized, restored, or destroyed when its owner is minimized, restored, or destroyed. Owned forms are good for floating-tool windows or FindReplace- type dialog boxes. The code in Ex am ple 4- 5 creates an ownerowned relationship. Compile it with this command: vbc filename.vb r:System.dll,System.Drawing.dll,System.Windows.Forms.dll t:winexe Example 4-5. Creating a form with an owner Imports System.Drawing Imports System.Windows.Forms Module modMain System.STAThreadAttribute Public Sub Main System.Threading.Thread.CurrentThread.ApartmentState = _ System.Threading.ApartmentState.STA System.Windows.Forms.Application.RunNew MyOwnerForm End Sub End Module Public Class MyOwnerForm Inherits Form Public Sub New Set my size. Me.ClientSize = New System.Drawing.Size600, 450 Create and show an owned form. Dim frm As New MyOwnedFormMe frm.Show End Sub End Class Public Class MyOwnedForm Inherits Form Public Sub NewByVal Owner As Form Set my owner. Me.Owner = Owner End Sub End Class4.4 MDI Applications
Parts
» VB.NET - (O'Reilly) Programming Visual Basic NET
» What Is the Microsoft .NET Framework?
» hello, world An Example Visual Basic .NET Program
» Hello, Windows An Example Visual Basic .NET Program
» Hello, Browser An Example Visual Basic .NET Program
» Source Files Identifiers The Visual Basic .NET Language
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» Interfaces The Visual Basic .NET Language
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» A Brief Tour of the .NET Framework Namespaces
» Configuration File Format Configuration
» Configuration Section Groups The appSettings Section
» Adding event handlers Creating a Form in Code
» Handling Form Events Windows Forms I: Developing Desktop Applications
» Relationships Between Forms Windows Forms I: Developing Desktop Applications
» Merging Menus MDI Applications
» Detecting MDI Child Window Activation
» Component Attributes Windows Forms I: Developing Desktop Applications
» The Graphics Class 2-D Graphics Programming with GDI+
» The Pen Class 2-D Graphics Programming with GDI+
» The Brush Class 2-D Graphics Programming with GDI+
» System colors The Color Structure
» Alpha Blending 2-D Graphics Programming with GDI+
» Antialiasing 2-D Graphics Programming with GDI+
» The PrintPageEventArgs Class Printing
» The OnBeginPrint and OnEndPrint Methods Choosing a Printer
» The PageSettings Class Printing
» The PrinterSettings Class Printing
» Page Setup Dialog Box Print Preview
» Summary Windows Forms I: Developing Desktop Applications
» The Button Class The CheckBox Class The ComboBox Class
» The DateTimePicker Class The GroupBox Class The ImageList Class
» The Label Class The LinkLabel Class
» The ListBox Class Common Controls and Components
» The ListBox.ObjectCollection Class
» The ListView Class Common Controls and Components
» The MonthCalendar Class Common Controls and Components
» The Panel Class The PictureBox Class
» The RadioButton Class Common Controls and Components
» The TextBox Class The Timer Class
» Other Controls and Components
» Control Events Windows Forms II: Controls, Common Dialog Boxes, and Menus
» The Anchor Property Form and Control Layout
» Controlling dock order The Dock Property
» The Splitter control The Dock Property
» ColorDialog FontDialog OpenFileDialog Common Dialog Boxes
» PageSetupDialog PrintDialog PrintPreviewDialog SaveFileDialog
» Adding Menus in the Visual Studio .NET Windows Forms Designer
» Programmatically Creating Menus Menus
» Building Controls from Other Controls
» Building Controls That Draw Themselves Building Nonrectangular Controls
» Summary Windows Forms II: Controls, Common Dialog Boxes, and Menus
» Setting control properties using attributes Adding event handlers
» AutoEventWireup Handling Page Events
» The Button control Web Controls
» The CheckBox control The DropDownList control
» The Image control The Label control
» The ListBox control Web Controls
» The RadioButton control Web Controls
» The Table control Web Controls
» The TextBox control Web Controls
» Other web controls Web Controls
» HTML Controls Handling Control Events
» Programmatically Instantiating Controls More About Server Controls
» More About Validation-Control Tag Attributes
» Using Validation-Control Properties Providing a Summary View of Validation Failures
» Performing Custom Validation Adding Validation
» Using Directives to Modify Web Page Compilation
» The Server Object ASP.NET Objects: Interacting with the Framework
» The Application Object The Session Object The Cache Object The Request Object
» The Response Object ASP.NET Objects: Interacting with the Framework
» Discovering Browser Capabilities ASP.NET and Web Forms: Developing Browser-Based Applications
» The Session Object Maintaining State
» The Application Object Maintaining State
» Session and Application Startup and Shutdown global.asax Compiles to a Class
» Adding Global Objects Application-Level Code and global.asax
» ASP.NET authorization Authorization
» Windows NTFS authorization Code-access authorization
» IUSR_ComputerName Impersonation Accessing Network Resources
» User Controls Designing Custom Controls
» Creating a custom server control using Visual Studio .NET
» Creating a custom server control in code Using a custom server control in Visual Studio .NET
» Summary ASP.NET and Web Forms: Developing Browser-Based Applications
» The WebService Attribute The WebMethod Attribute
» Testing a Web Service with a Browser
» Consuming a Web Service in Visual Studio .NET
» Consuming a Web Service in Notepad
» Synchronous Versus Asynchronous Calls
» Web-Service Descriptions Web-Service Discovery
» Limitations of Web Services Summary
» A Brief History of Universal Data Access Managed Providers
» Connecting to a SQL Server Database
» Connecting to an OLE DB Data Source
» The DataSet Class Finding Tables
» Finding Column Values Finding Column Definitions Changing, Adding, and Deleting Rows
» Writing Updates Back to the Data Source
» Relations Between DataTables in a DataSet
» The DataSets XML Capabilities
» Binding a DataSet to a Windows Forms DataGrid
» Binding a DataSet to a Web Forms DataGrid
» Typed DataSets ADO.NET: Developing Database Applications
» Reading Data Using a DataReader
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