Session 4Session 4From Access Forms to From Access Forms to Windows Forms .NET Windows Forms .NET

Adam CoganDatabase Architectssw.com.au

ToToFromFrom

OverviewOverview

Access 97 Access 97 toto

Access 2003Access 2003

AccessAccesstoto

SQL ServerSQL Server

AccessAccesstoto

ReportingReportingServicesServices

AccessAccesstoto

WindowsWindowsForms .NETForms .NET

11 22 33 44

AgendaAgenda• Current Problems• What’s New in .NET• Lab: Migrating from Access

Forms to Windows Forms .NET

Breezers Drink Receipt From Outback Oz

AssumptionsAssumptions• Backend in SQL Server 2000• Using Enterprise Manager for data

management• Access forms front-end• Reports using Reporting Services• Some VBA knowledge

Session Prerequisites (Current Problems)Session Prerequisites (Current Problems)

1. “Our application stopped working on Mary’s machine when we installed the new version of Office”

2. “Our Access database got corrupted and we can’t open it”

3. “Our Access forms run too slowly - we want a small, fast EXE”

4. “Can we stop the continual polling of SQL Server so we can scale this application?”

5. “We want to integrate with other systems”

Enter .NETEnter .NET• No need for Access runtime or Office

for end-user (1)• Produce an EXE which doesn’t get

corrupted like an MDB (2)• The EXE is small and runs fast (3)• Only explicit updates to database (4)• Web Service Support are built in (use

an open XML-based architecture) (5)

Problems with Bound Access Problems with Bound Access FormsForms

Advantage – Database Connections are Controllable

In Access• Forms perform database queries in the

background• Cannot be controlledIn .NET• Full control over database connections and

queries• Improved performance and scalability

Not as smooth a ride

Problems with Bound Access Problems with Bound Access FormsForms

Advantage – Database Connections are Controllable

In Access

In .NET

Differences In Form DesignDifferences In Form DesignAdvantage – A Shallow Learning Curve for Access

Developers (1 of 2)

Differences In Form DesignDifferences In Form DesignAdvantage – A Shallow Learning Curve for Access

Developers (2 of 2)

Northwind .NETNorthwind .NET

Differences In Form DesignDifferences In Form DesignNew Feature – Anchoring Controls

Differences In Form DesignDifferences In Form DesignNew Feature – Docking Controls

Differences In Form DesignDifferences In Form DesignAdvantage – Powerful New Controls (1 of

2)

Differences In Form DesignDifferences In Form DesignAdvantage – Powerful New Controls (2 of

2)

Data FormsData FormsIn Access

1. Get Data – Make Queries

Data FormsData FormsIn Access

2. Bind – Set the One RecordSource

Data FormsData FormsIn Access

3. Bind – Set the ControlSource for all bound controls

Data FormsData FormsIn .NET

1. Get Data – Create Data Components (DataSets and DataAdapters)

Data FormsData FormsIn .NET

2. Bind – Set the Many Referenced DataSets

Data FormsData FormsIn .NET

3. Bind – Set the DataBindings for all bound controls

Differences In Form DesignDifferences In Form DesignDisadvantage – Database Updates Are

Not Done AutomaticallyIn Access

1. Changes made on forms are automatically saved

In .NET:1. Add a save button2. Call DataAdapter.Update(DataSet) in

the OnClick event

Differences in Application DesignDifferences in Application DesignAdvantage – All .NET Solution Items are Described

in Plain TextIn Access• Everything is in the MDB• If damaged, everything stops workingIn .NET• All solution items are in plain text• Forms described in XML• Low chance of corruption• Lightweight

Differences In Form DesignDifferences In Form DesignDifference – Data ViewsAccess Visual Studio .NET

Design Supported

Form Compile and Run Application

Datasheet Not supported

NavigationNavigation

Private Sub previousRecord_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles previousRecord.Click ' Check that the user isn't on the first record. If Not Me._ordersManager.Position = 0 Then _movingRecords = True Me._ordersManager.Position -= 1 _movingRecords = False End If End Sub

Private Sub nextRecord_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles nextRecord.Click ' Check that the user isn't on the last record. If Not Me._ordersManager.Position = Me._ordersManager.Count - 1 Then _movingRecords = True Me._ordersManager.Position += 1 _movingRecords = False End If End Sub

Add / Edit Line ItemsAdd / Edit Line Items

Private Sub editItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles editItem.Click ' Check that there is a row to edit. If Not BindingContext(ordersList, "Orders.OrdersOrder_Details").Position = -1 Then Dim cm As CurrencyManager = CType(BindingContext(ordersList, "Orders.OrdersOrder_Details"), CurrencyManager)

' Get the current row. Dim orderItem As OrdersDataSet.Order_DetailsRow = CType(CType(cm.Current, DataRowView).Row, OrdersDataSet.Order_DetailsRow)

' Pass the current row to the Order Details form. Dim orderDetailsForm As New OrderDetailsPopupForm(orderItem)

' Show the Order Details form and return the result. Dim result As DialogResult = orderDetailsForm.ShowDialog() ' Check if the user clicked "OK".

If result = DialogResult.OK Then CalculateTotals() End If End If End Sub

Save DataSave Data

Private Sub btnOK_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnOK.Click Me._ordersManager.EndCurrentEdit() ' Check if changes were made If ordersList.HasChanges Then ' Update the Orders table _ordersDA.Adapter.Update(ordersList) ' Update the Order Details table _orderDetailsDA.Adapter.Update(ordersList) End If End Sub

Differences In Form DesignDifferences In Form DesignDisadvantage – Multiple Columns Not

Supported in Some Controls• Use .NET ListView instead of Access Listbox• Some programming required for multi-

column ComboBox

Differences In Form DesignDifferences In Form DesignDisadvantage – Multiple Columns Not

Supported in Some Controls

Differences In Form DesignDifferences In Form DesignDisadvantage – The Datasheet View Is Harder

to ImplementIn Access• View – DatasheetIn .NET:• Use DataGrid control• Manually bind to database• Hard to implement advanced controls (ComboBox

etc.)

Differences In Form DesignDifferences In Form DesignDisadvantage – Continuous Forms Are Harder

to Implement (1 of 4)In Access• Form Property: Default View = Continuous

Forms In .NET• Not supported in .NET• 2 options

– Tiled user controls– Summary/Detail

Differences In Form DesignDifferences In Form DesignDisadvantage – Continuous Forms Are Harder

to Implement (2 of 4)• Tiled user controls

Differences In Form DesignDifferences In Form DesignDisadvantage – Continuous Forms Are Harder

to Implement (3 of 4)• Split into summary/detail for complex

subforms

Differences In Form DesignDifferences In Form DesignDisadvantage – Continuous Forms Are Harder

to Implement (4 of 4)• Split into summary with popup window

Differences In Form DesignDifferences In Form DesignDisadvantage – Subforms are Easier to Use than User

Controls (1 of 2)In Access1. Create parent and sub forms2. Add subform/subreport to parent3. Set linkages between parent/subform

Differences In Form DesignDifferences In Form DesignDisadvantage – Subforms are Easier to Use than User Controls (2 of

2)In .NET1. Create Orders form (parent)2. Create user control for Orders Subform form3. Add property to user control to link parent and subform (code)4. Update the Orders Subform (user control) when the parent

record changes (code)5. Add the Orders Subform (user control) to the Orders form6. Bind the Orders form to the Orders Subform (user control)

Note: We take a different approach with our example (popup window)

Differences In Form DesignDifferences In Form DesignAdvantage – Form Inheritance1. Add any common form controls and

logic into a base form2. Create new instances of (“inherit”)

the parent form to ensure consistency

3. Make any required changes to logic and controls on child forms

Differences In Form DesignDifferences In Form DesignAdvantage – Use Windows XP Styles• Easy to implement in .NET

Differences In Form DesignDifferences In Form DesignDisadvantage – Read-Only Textboxes are Grayed

OutIn Access• Set Locked = YesIn .NET• Set ReadOnly = True• Have to explicitly set the background colour

Differences In Form DesignDifferences In Form DesignDisadvantage – Combo Boxes Cannot Be

LockedIn Access• Set Locked = YesIn .NET• No automatic way• Capture the SelectedIndexChanged

event and reset the value

Differences In Form DesignDifferences In Form DesignAdvantage – Applications Are Stored As

Binary ExecutablesIn Access• Use compact and repair• Manually compile as MDEIn .NET• Application automatically compiled on

run• Runs efficiently because it is in binary

Differences in Application DesignDifferences in Application DesignAdvantage – Application Deployment is

EasierIn Access:• License for Office Developer Edition

(for runtime), or• Office installed on target machineIn .NET you only need the free .NET

Framework

Differences in Application DesignDifferences in Application DesignAdvantage – .NET Versions Can Be Run Side-by-SideIn Access:• Upgrading Office can cause issues (as we have

seen)• Can have multiple versions of Office installed –

however MDB associations don’t know enoughIn .NET:• Framework versions can run side-by-side• Apps using 1.0 continue to work alongside 1.1

Advantage – Extending Your Forms to Mobile Devices

?.NET Web Service

Business and Data Access Logic

Differences in Application DesignDifferences in Application Design

Differences in Application DesignDifferences in Application DesignDifference – Security Model Integrates with

WindowsIn Access• Maintain two sets of security for forms

(Access) and backend (SQL)

Differences in Application DesignDifferences in Application DesignDifference – Security Model Integrates

with WindowsIn .NET• Use Windows Integrated security• Based on Active Directory – one model

for forms and SQL Server• Check user’s role in code (using

System.Security.Principal namespace)

Differences in Application DesignDifferences in Application DesignDisadvantage – No Wizard-Based

SecurityIn Access:• Use the User-level Security Wizard to

automatically set object permissionsIn .NET:• Form permissions must be defined in

code

Differences in ProgrammingDifferences in ProgrammingDifference – VBA replaced by VB.NETIn Access you use• VBA• .DLLsIn .NET• VB.NET, C#, J# etc.• Can use components written in other

languages

Differences in ProgrammingDifferences in ProgrammingAdvantage – Improved Language Features• Structured exception handling• Form and code inheritance• XML and XSL functionality for web services• Simple API wrappers – less API calls

– accessing printers– file dialog boxes

• Improved internationalisation and regional customisation

• Create and deploy DLLs, user controls and web services in .NET

Differences in ProgrammingDifferences in ProgrammingDifference – Macros replaced by VB .NETIn Access you use • the visual macro designerIn .NET• you must rewrite as codeTip: Use the Macro to VBA converter to

simplify rewriting

Differences in ProgrammingDifferences in ProgrammingDifference – Responding to Form Events• .NET – new “Handles” keyword• One method can handle multiple

events

• All Access form events can be handled

Private Sub OpenCustomer (…) Handles btnOK.Click, cboCustomers.DoubleClick…End Sub

Differences in ProgrammingDifferences in ProgrammingAdvantage – Improved Development

Environment (1 of 3)• Improved Intellisense

Differences in ProgrammingDifferences in ProgrammingAdvantage – Improved Development

Environment (2 of 3)• Improved design-time debugging

Differences in ProgrammingDifferences in ProgrammingAdvantage – Improved Development

Environment (3 of 3)• Visually build database objects

Differences in ProgrammingDifferences in ProgrammingAdvantage – Use Unit Testing Tools to Check Your

Code• Cannot test code in Access• .NET supports testing frameworks eg. nUnit

Differences in ProgrammingDifferences in Programming

Difference – Autoexec Macros vs. Startup Forms/Stubs

• In Access:– Startup form– Autoexec Macro

• In .NET:– Select form in project properties– Shared Sub Main()

SummarySummary• Current Problems

– New versions of Office cause applications to stop working

– Corrupt Access databases– Slow, large Access forms– Continual automatic polling of SQL Server,

limiting scalability– Hard to integrate with other systems

• What’s New in .NET• Lab: Migrating Access forms to .NET

For More Information…For More Information…Microsoft Access: Upgrading and Migrating to SQL Server and .NET -

Course Resourceswww.ssw.com.au/ssw/Events/2004AccessToSQLServerAndNET/

Resources.aspxwww.microsoft.com/net

More courses in March – see www.microsoft.com/australia/events/

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