DEV393.NET Windows Forms Tips and Tricks Ken Getz Senior Consultant MCW Technologies, LLC

Me.About Senior Consultant with MCW Technologies, LLC Microsoft Regional Director, SoCal Technical editor for Access-VB-SQL Advisor ( Author of several developer’s books on ASP.NET, VB, Access, and VBA ASP.NET, VB.NET, ADO.NET, VB6 and Access video training for AppDev (

Special Thanks… Half of the topics in this session developed by Shawn Burke Development Manager,.NET Client Team

Eight Real-World Tips 1.Display Controls Your Way Owner-drawn ListBox and MenuItem 2.Use Data to Control the User Interface Working with the data bindings 3.Expose Protected Info with Inheritance Synchronized scrolling DataGrids 4.Improve the Look of Your Application Add XP Theming and non-rectangular windows

Eight Real-World Tips 5.Avoid Work When Drawing Controls ControlPaint class 6.Control DataGrid Formatting and Data Entry Use Column styles and DataView properties 7.Handle Single-Threaded Forms Use Invoke to handle thread switch 8.Allow Users to Easily Modify Settings Use the PropertyGrid control in your app!

Display Controls Your Way Use GDI+ to handle painting yourself Applies to (among others): ListBox/ComboBox MenuItem (set OwnerDraw property to True) For ListBox/ComboBox, set DrawMode property to one of: Normal OwnerDrawFixed OwnerDrawVariable

Drawing the Items Provide code for two events: MeasureItem Provide the width and height for each item Not used for List/ComboBox if DrawMode set to OwnerDrawFixed DrawItem Draw the item using GDI+ in the rectangle provided

It’s all in DrawEventArgs DrawEventArgs parameter provides: Bounds property: Rectangle containing the item Graphics property: Graphics context Index property: Index of current item State property: bit-flag property indicating current state of the item being drawn DrawBackground method DrawFocusRectangle method

Create Owner-Drawn ListBox and MenuItem demo demo

Using Data To Control UI Data binding can be used for more than just data Data binding infrastructure is very general and can bind almost any property to almost any value Notifications based on property change events Applications often want to show/hide/disable/enable controls based on the state of other controls

Controlling UI With Databinding demo demo

Expose Protected Info Much functionality of WinForms controls is protected Only available in control class, and in classes that inherit from the control What if you want to use protected functionality yourself? Must inherit from the control, and expose Can create real custom control Or can simply create a class in your project

Create Synchronized Scrolling DataGrids demo demo

Improving the Look of your Application Integrating Windows XP Visual Styles with your application Many controls can theme: system controls, ListView, TreeView, TabControl, Progress Bar Windows 2000, Windows XP Allow transparent top-level windows Control shapes can be modified with regions

Theming your Windows Forms Application demo demo

Avoid Work Drawing Three ways to create custom controls: Inherit from existing Create UserControl and its design surface Draw yourself, using GDI+ The last option made easier through the magic of the ControlPaint class Provides shared methods so you can easily create modified versions of standard controls

Create a Resizable Checkbox Control demo demo

Formatting a DataGrid Control By default, DataGrid shows all columns in all tables Using default settings for color, width, and formatting What if you want more control over the way the data looks? Use the GridTableStylesCollection Collection of DataGridTableStyle objects

Configuring with Properties Window Check out the TableStyles property Set MappingName property to match DataMember providing data Can also set general settings here Select GridColumnStyles to set up individual column styles Adds DataGridColumnStyle objects Set MappingName property (column name) Can set ReadOnly (see ProductID column) Show code generated by the designer

Writing Code You can also write code to manipulate styles: Dim dgCol As DataGridTextBoxColumn = _ CType(Me.styleOrderDetails. _ GridColumnStyles(2), DataGridTextBoxColumn) dgCol.Format = "c" dgCol.Alignment = HorizontalAlignment.Right

Limit Editing in DataGrid What if you want to allow edits, but not additions? Deletions, but not edits? Can set DataTable to be read-only, but that doesn't help DataView to the rescue Provides AllowEdit, AllowNew, AllowDelete properties All based on DataGrid binding to DataView

Formatting Columns and Handling Editing demo demo

Forms Aren’t Thread-Safe Call a Web Service asynchronously CLR retrieves a background thread from the thread pool Callback runs on the background thread Forms aren’t thread-safe You can’t reliably interact with the form from a background thread Can’t handle multiple threads updating properties concurrently

The Invoke Method Form (actually Control) provides Invoke method Runs a delegate on the thread that owns the form/control's window Calling Invoke performs a thread switch, and runs the called code on the host’s thread

Solving the Problem Examine the Original Code Create a Delegate Type Create the Delegate Instance and Call It Use Invoke method Pass array containing all parameters Sample displays thread information So you can verify the running thread

Handle Thread Switch using Invoke Method demo demo

Using the PropertyGrid in Your Application The PropertyGrid is the heart of the Property Browser in Visual Studio.NET The PropertyGrid provides a simple model for displaying property settings Easier and more space-efficient than laying out a dialog Can use a serializable object with properties to display, save, and load state

Using the PropertyGrid in Your Application demo demo

Ask The Experts Get Your Questions Answered Stop by Ask the Experts area 16:00 to 17:00, Wednesday

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