Data Binding in Windows Forms

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Data Binding in Windows Forms
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What can be bound

• Windows Forms can bind to
• the public properties of a class
• any class that supports the IList interface
• The IList interface does not include a concept of
  position.
• ASP.NET Web Forms allows binding to the
  DataReader object or the IEnumerable interface
  because forward-only scrolling is acceptable

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Binding Managers

• The Windows Forms object model supports two
  different binding managers
• PropertyManager, binds simple controls to public
  properties of a class.
• CurrencyManager, binds simple or complex controls
  to an object that supports the IList interface

4
Binding Overview
Form
DataBindings
Control
BindingContext
Binding
ControlBindingsCollection
Binding
Binding
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DataBindings

• Maintains the ControlBindingsCollection, which
  holds Binding objects
• Be consistent in binding expressions
• Control1.DataBindings.Add(Text, ds, table1.X)
• Control1.DataBindings.Add(Text, ds.table1, X)

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Currency Manager

• Has a one to one relationship with a data source
• Created by form when first Binding is added
• Maintains the current position in the list.
• Exposes a PositionChanged event.
• Ensures controls show data from the same record.

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Binding Context

• The forms BindingContext property
• Is typed as base class BindingManagerBase
• bc Me.BindingContext(ds, "Customers")
• Needs to cast to correct derived type
• CurrencyManager
• Get the underlying bound collection from the List
  property.
• cm CType(bc, CurrencyManager)
• dv CType(cm.List, DataView)
• al CType(cm.List, ArrayList)
• PropertyManager
• Get the underlying bound object from the Current
  property
• pm CType(bc, PropertyManager)
• MyObject CType(pm.Current, MyClass)

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Binding to ADO.NET Data Objects

• DataColumn object
• You can simple-bind a control to a column within
  a data table. Each DataColumn object has a
  DataType property that determines the kind of
  data the column holds
• DataTable object
• When you bind to a DataTable, you are a really
  binding to the table's default view.
• DataView object
• A customized view of a single data table that may
  be filtered or sorted. A data view is the data
  "snapshot" used by complex-bound controls. You
  can simple- or complex-bind to the data within a
  data view, but be aware that you are binding to a
  fixed "picture" of the data rather than a clean,
  updating data source.
• DataSet object
• You are actually binding to the DataSet's default
  DataViewManager
• DataViewManager object
• A customized view of the entire DataSet,
  analogous to a DataView, but with relations
  included.

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DataView

• Typically the bound object
• Use to change data programatically, not the UI
• implements IBindingList
• ListChangedEvent, notifies any user changes (such
  as additions, deletions, or sorting)

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Table Styles

• Can have multiple table styles, only one selected
  at a time.
• Each table style can map to a different data
  source
• Set the TableStyles MappingName at run time to
  select it.
• TableStyle1.MappingName Table1
• TableStyle2.MappingName

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Table Style Columns

• Custom column are needed to
• handle columns that show a button, combobox or
  other control in the grid
• set column read-only
• special case formatting

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• Roadmap for Windows Forms Data Binding PSS ID
  Number 313482
• George Shepherds Windows Forms FAQ
• http//www.syncfusion.com/FAQ/WinForms/
• BlueVision Publishing Books
• http//www.akadia.com/services/dotnet_databinding.
  html