Transcript The DataGrid, a Complex-Bound .NET GUI control

The Windows Forms
DataGrid
A Complex-Bound
.NET GUI Control
MikeFITZSIMON
SYSTEMSARCHITECT
FITZSIMON IT CONSULTING PTY LTD
Simple vs Complex Binding
 simple binding :
binding a control to a single data column. A
TextBox is an example of a control that can
be simply bound.
 complex binding :
binding more than one column to a single
control. The DataGrid is an example of a
control that can be complexly bound.
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Retrieving and Updating Data
 Add a new connection
(in Server Explorer, right-click Data
Connections and choose Add Connection)
 Connect the form to the tables
(in Server Explorer, drag table icons to the
form. An OleDbDataAdapter is created for
each table, and an OleDbConnection to the
database is also added)
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Demo
 Northwind.mdb
 Three tables: Customers, Orders, Order
Details
 Display in DataGrid
 Update in DataGrid
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Danger, Will Robinson!
 The three tables are related in the database,
but no relations exist between them in the
DataSet.
 Editing in the DataGrid can create
inconsistent data in the DataSet.
 dataAdapter.Update will fail
 Avoid this by adding DataRelation objects to
your DataSet
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Proper Case Column Headers
 When setting a DataGrid’s data source
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programmatically, cannot assign column header
names at design time.
The DataGrid uses the recordset’s column names.
Often these recordset column names may be
confusing, not to mention unprofessional looking.
Work-around: use alias field names in the SQL
statement for the underlying data source.
E.g., in a SQL statement, instead of:
SELECT pub_id, pub_name FROM pubs
Use:
SELECT pub_id AS ID, pub_name AS
Publisher FROM pubs
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Data binding with a collection
 A collection can be populated with simple data, such
as strings, and bound to a list box control.
 Dim objCollection As New Collection()
objCollection.Add("Value
objCollection.Add("Value
objCollection.Add("Value
objCollection.Add("Value
1")
2")
3")
4")
ListBox1.DataSource = objCollection
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Custom objects bound directly to a
DataGrid control

Create a new class
Public Class MyData
Private cstrValue1 As String
Private cstrValue2 As String
Public Sub New(ByVal Value1 As String, ByVal Value2 As String)
cstrValue1 = Value1
cstrValue2 = Value2
End Sub
Public Property Value1() As String
Get
Return cstrValue1
End Get
Set(ByVal Value As String)
cstrValue1 = Value
End Set
End Property
Public Property Value2() As String
Get
Return cstrValue2
End Get
Set(ByVal Value As String)
cstrValue2 = Value
End Set
End Property
End Class
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Custom objects bound directly to a
DataGrid control
 Next, add a data grid control to the form, and
add the following code to the form Load
event:
 Dim objCollection As New Collection()
objCollection.Add(New
objCollection.Add(New
objCollection.Add(New
objCollection.Add(New
MyData("Value
MyData("Value
MyData("Value
MyData("Value
1",
2",
3",
4",
DataGrid1.DataSource = objCollection
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"Test
"Test
"Test
"Test
1"))
2"))
3"))
4"))
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Questions
 Mike Fitzsimon
[email protected]
 Sample code & this ppt available from
www.fitzsimon.com.au/qmsdnug
Fitzsimon IT CONSULTING PTY LTD
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