data-driven - 1 © minder chen, 2002-2007 building data-driven web sites in asp.net 2.0

Data-Driven - 1 © Minder Chen, 2002-2007

Building Data-Driven Web Sites in ASP.NET 2.0

Codeless Data-Binding Process

Source: http://beta.asp.net/QUICKSTART/aspnet/doc/ctrlref/data/default.aspx

Data Bound Controls

• DataGrid

• DataList

• GridView

• DetailsView

• FormView • Repeater

New inASP.NET 2.0

Data-Bound Controls

• <asp:GridView>

• <asp:DataGrid>

• <asp:DetailsView>

• <asp:TreeView>

• <asp:Menu>

• <asp:DataList>

• <asp:Repeater>

• <asp:DropDownList>

• <asp:BulletedList>

• <asp:CheckBoxList>

• <asp:RadioButtonList>

• <asp:ListBox>

• <asp:AdRotator>

Data Bound Controls and Data Source Controls

Create a New Data Source

• Drag and drop the AccessDataSource Web server control on to a Web form.

• Click the smart tab of the AccessDataSource1 to select common tasks for the AccessDataSource

• Click on the Configure Data Source… taskSmart tag

Smart tag menu

Select the Access database

Define a SQL (Select) statement

SELECT [CategoryID], [CategoryName], [Description] FROM [Categories]

Don't choose any query name if you need to create a data source that will be used to insert, update, or delete data in the database.

Test Query

<asp:AccessDataSource ID="AccessDataSource1" runat="server" DataFile="~/App_Data/northwind.mdb"

SelectCommand="SELECT [CategoryID], [CategoryName], [Description] FROM [Categories]">

</asp:AccessDataSource>

CategoryList.aspx

Connecting Data Source and GridView

• Drop and drop a GridView to the Web form • From the GridView smart tag menu, click on the

dropdown listbox -- Choose Data Source and then select AccessDataSource1

Edit Columns…

Create a HyperLinkField for the CategoryName Column

• Delete the CategoryName from the Selected Fields list box

• Highlight HyperlinkField and click Add

• Move the HyperLinkField to the position between CategoryID and Description in the Selected Fields list box

• Set up the properties of the HyperlinkField

Set up HyperlinkField• Set up the Hyperlink field so that it displays CategoryName as the

link words, and links to ProductsByCategory.aspx while passing two QueryString variables cid and cname where cid contains CategoryID and cname contains CategoryName

ProductsByCategory.aspx?cid={0}&cname={1}

CategoryID, CategoryName

CategoryIDCategoryName

Source Code <asp:GridView ID="GridView1" runat="server"

AutoGenerateColumns="False" DataKeyNames="CategoryID" DataSourceID="AccessDataSource1"> <Columns> <asp:BoundField DataField="CategoryID"

HeaderText="CategoryID" InsertVisible="False"

ReadOnly="True" SortExpression="CategoryID" /> <asp:HyperLinkField

DataNavigateUrlFields="CategoryID, CategoryName" DataNavigateUrlFormatString=

"ProductsByCategory.aspx?cid={0}&cname={1}" DataTextField="CategoryName" HeaderText="Category Name" /> <asp:BoundField DataField="Description" H

HeaderText="Description" SortExpression="Description" /> </Columns> </asp:GridView>

CategoryList.aspx<%@ Page Language="VB" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"><script runat="server"></script><html xmlns="http://www.w3.org/1999/xhtml" ><head runat="server"> <title>Untitled Page</title></head><body> <form id="form1" runat="server"> <div> <h1> Category List</h1> <p> <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" DataKeyNames="CategoryID" DataSourceID="AccessDataSource1"> <Columns> <asp:BoundField DataField="CategoryID" HeaderText="CategoryID" InsertVisible="False" ReadOnly="True" SortExpression="CategoryID" /> <asp:HyperLinkField DataNavigateUrlFields="CategoryID, CategoryName"

DataNavigateUrlFormatString="ProductsByCategory.aspx?cid={0}&cname={1}" DataTextField="CategoryName" HeaderText="Category Name" /> <asp:BoundField DataField="Description" HeaderText="Description" SortExpression="Description" /> </Columns> </asp:GridView> <asp:AccessDataSource ID="AccessDataSource1" runat="server" DataFile="~/App_Data/northwind.mdb" SelectCommand="SELECT [CategoryID], [CategoryName], [Description] FROM [Categories]"> </asp:AccessDataSource> </p> </div> </form></body></html>

ProductsByCategory.aspx

• Choose Data Source

• Edit Data Source

Define the SQL Statement

SELECT [ProductID], [ProductName], [Discontinued], [UnitPrice] FROM [Products] WHERE ([CategoryID] = ?)

Make sure you choose

Products table

Add Where Clause

Parameterized Commands

• Parameter properties – Parameterized database commands

• Example: – Get value for WHERE clause in

SelectCommand from QueryString parameter or item selected in a drop-down list Web server control

• Example: – Get value for WHERE clause in

DeleteCommand from GridView

Parameters Properties

Name Description

SelectParameters Specifies parameters for SelectCommand

InsertParameters

UpdateParameters

DeleteParameters

FilterParameters Specifies parameters for FilterExpression

Specifies parameters for InsertCommand

Specifies parameters for UpdateCommand

Specifies parameters for DeleteCommand

Parameter Types

NameName DescriptionDescription

ControlParameter Binds a replaceable parameter to a control property

CookieParameter Binds a replaceable parameter to a cookie value`

FormParameter Binds a replaceable parameter to a form field

ProfileParameter Binds a replaceable parameter to a profile property

QueryStringParameter Binds a replaceable parameter to a query string parameter

Parameter Binds a replaceable parameter to a data field

SessionParameter Binds a replaceable parameter to a session variable

Test Query

AutoFormat

TemplateField

Code for TemplateField <asp:TemplateField HeaderText="ProductName" SortExpression="ProductName">

<asp:Label ID="Label1" runat="server" Text='<%# Bind("ProductName") %>'></asp:Label>

</ItemTemplate>

<asp:TextBox ID="TextBox1" runat="server" Text='<%# Bind("ProductName") %>'></asp:TextBox>

</EditItemTemplate>

</asp:TemplateField>

Edit Template

Set Up Text property

Set up NavigateUrl property

• ProductRecord.aspx?pid={0}

End Template Editing

ProductsByCategory.aspx

<%@ Page Language="VB" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">

Continued…<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" DataKeyNames="ProductID" DataSourceID="AccessDataSource1" BackColor="White" BorderColor="#CC9966" BorderStyle="None" BorderWidth="1px" CellPadding="4" ><Columns> <asp:BoundField DataField="ProductID" HeaderText="ProductID"

InsertVisible="False" ReadOnly="True" SortExpression="ProductID" /> <asp:TemplateField HeaderText="Product Name" SortExpression="ProductName"> <ItemTemplate> <asp:HyperLink ID="HyperLink1" runat="server" NavigateUrl='<%# Eval("ProductID", "ProductRecord.aspx?pid={0}") %>' Text='<%# Eval("ProductName") %>'></asp:HyperLink> </ItemTemplate> <EditItemTemplate> <asp:TextBox ID="TextBox1" runat="server"

Text='<%# Bind("ProductName") %>'></asp:TextBox> </EditItemTemplate></asp:TemplateField>

Continued…<asp:CheckBoxField DataField="Discontinued"

HeaderText="Discontinued" SortExpression="Discontinued" />

<asp:BoundField DataField="UnitPrice" HeaderText="UnitPrice" SortExpression="UnitPrice" DataFormatString="{0:c}" >

<ItemStyle HorizontalAlign="Right" /> </asp:BoundField></Columns><FooterStyle BackColor="#FFFFCC" ForeColor="#330099" /><RowStyle BackColor="White" ForeColor="#330099" /><PagerStyle BackColor="#FFFFCC" ForeColor="#330099"

HorizontalAlign="Center" /><SelectedRowStyle BackColor="#FFCC66" Font-Bold="True"

ForeColor="#663399" /><HeaderStyle BackColor="#990000" Font-Bold="True"

ForeColor="#FFFFCC" />

</asp:GridView>

Continued…

<asp:AccessDataSource ID="AccessDataSource1" runat="server" DataFile="~/App_Data/northwind.mdb" SelectCommand="SELECT [ProductID], [ProductName], [Discontinued], [UnitPrice] FROM [Products] WHERE ([CategoryID] = ?)">

<SelectParameters> <asp:QueryStringParameter DefaultValue="1"

Name="CategoryID" QueryStringField="cid" Type="Int32" /> </SelectParameters> </asp:AccessDataSource> </div> </form></body></html>

ProductRecord.aspx Runtime

Define the SQL StatementSELECT [ProductID], [ProductName], [CategoryID], [UnitPrice],

[UnitsInStock], [Discontinued] FROM [Products] WHERE ([ProductID] = ?)

Add Where Clause

Use DetailsView (One Record at a Time)

Format the DetailsView

ProductRecord.aspx<%@ Page Language="VB" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"><script runat="server"></script><html xmlns="http://www.w3.org/1999/xhtml" ><head runat="server"> <title>Untitled Page</title></head><body> <form id="form1" runat="server"> <div> <h1>Product Record</h1> <asp:DetailsView ID="DetailsView1" runat="server" AutoGenerateRows="False" CellPadding="4" DataKeyNames="ProductID" DataSourceID="AccessDataSource1"

Font-Bold="False" ForeColor="#333333" GridLines="None" Height="50px"> <FooterStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" /> <CommandRowStyle BackColor="#D1DDF1" Font-Bold="True" /> <RowStyle BackColor="#EFF3FB" /> <FieldHeaderStyle BackColor="#DEE8F5" Font-Bold="True" /> <PagerStyle BackColor="#2461BF" ForeColor="White" HorizontalAlign="Center" /> <Fields> <asp:BoundField DataField="ProductID" HeaderText="ProductID" InsertVisible="False" ReadOnly="True" SortExpression="ProductID" />

<asp:BoundField DataField="ProductName" ItemStyle-Width="200px" HeaderText="ProductName" SortExpression="ProductName" />

<asp:BoundField DataField="CategoryID" HeaderText="CategoryID" SortExpression="CategoryID" />

Continued… <asp:BoundField DataField="UnitPrice" DataFormatString="{0:c}"

HeaderText="UnitPrice" SortExpression="UnitPrice"> </asp:BoundField>

<asp:BoundField DataField="UnitsInStock" DataFormatString="{0} in stock" HeaderText="UnitsInStock"

SortExpression="UnitsInStock" /> <asp:CheckBoxField DataField="Discontinued" HeaderText="Discontinued"

SortExpression="Discontinued" /> </Fields> <HeaderStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" /> <EditRowStyle BackColor="#2461BF" /> <AlternatingRowStyle BackColor="White" /> </asp:DetailsView> <asp:AccessDataSource ID="AccessDataSource1" runat="server"

DataFile="~/App_Data/northwind.mdb" SelectCommand="SELECT [ProductID], [ProductName], [CategoryID], [UnitPrice],

[UnitsInStock], [Discontinued] FROM [Products] WHERE ([ProductID] = ?)"> <SelectParameters> <asp:QueryStringParameter Name="ProductID"

QueryStringField="pid" Type="Int32" /> </SelectParameters> </asp:AccessDataSource> </div> </form></body></html>

Manage Categories

Define the SQL Statement

Use Optimistic Concurrency Control <asp:AccessDataSource ID="AccessDataSource1" runat="server" DataFile="~/App_Data/northwind.mdb" DeleteCommand="DELETE FROM [Categories] WHERE [CategoryID] = ? AND

[CategoryName] = ? AND [Description] = ?" InsertCommand="INSERT INTO [Categories] ([CategoryID], [CategoryName], [Description]) VALUES (?, ?, ?)" SelectCommand="SELECT [CategoryID], [CategoryName], [Description] FROM

[Categories]" UpdateCommand="UPDATE [Categories] SET [CategoryName] = ?, [Description] = ?

WHERE [CategoryID] = ? AND [CategoryName] = ? AND [Description] = ?" ConflictDetection="CompareAllValues"> <DeleteParameters> <asp:Parameter Name="original_CategoryID" Type="Int32" /> <asp:Parameter Name="original_CategoryName" Type="String" /> <asp:Parameter Name="original_Description" Type="String" /> </DeleteParameters> <UpdateParameters> <asp:Parameter Name="CategoryName" Type="String" /> <asp:Parameter Name="Description" Type="String" /> <asp:Parameter Name="original_CategoryID" Type="Int32" /> <asp:Parameter Name="original_CategoryName" Type="String" /> <asp:Parameter Name="original_Description" Type="String" /> </UpdateParameters> <InsertParameters> <asp:Parameter Name="CategoryID" Type="Int32" /> <asp:Parameter Name="CategoryName" Type="String" /> <asp:Parameter Name="Description" Type="String" /> </InsertParameters>

</asp:AccessDataSource>

Without Optimistic Concurrency Control<asp:AccessDataSource ID="AccessDataSource1" runat="server" DataFile="~/App_Data/northwind.mdb" DeleteCommand="DELETE FROM

[Categories] WHERE [CategoryID] = ?" InsertCommand="INSERT INTO [Categories] ([CategoryID],

[CategoryName], [Description]) VALUES (?, ?, ?)" SelectCommand="SELECT [CategoryID], [CategoryName], [Description]

FROM [Categories]" UpdateCommand="UPDATE [Categories] SET [CategoryName] = ?,

[Description] = ? WHERE [CategoryID] = ?"> <DeleteParameters> <asp:Parameter Name="original_CategoryID" Type="Int32" /> </DeleteParameters> <UpdateParameters> <asp:Parameter Name="CategoryName" Type="String" /> <asp:Parameter Name="Description" Type="String" /> <asp:Parameter Name="original_CategoryID" Type="Int32" /> </UpdateParameters> <InsertParameters> <asp:Parameter Name="CategoryID" Type="Int32" /> <asp:Parameter Name="CategoryName" Type="String" /> <asp:Parameter Name="Description" Type="String" /> </InsertParameters> </asp:AccessDataSource>

CategoryUpdateGridView.aspx<%@ Page Language="VB" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"><script runat="server"> </script><html xmlns="http://www.w3.org/1999/xhtml" ><head runat="server"> <title>Untitled Page</title></head><body> <form id="form1" runat="server"> <div> <h1>Manage Categories</h1>

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" DataKeyNames="CategoryID"

DataSourceID="AccessDataSource1" AllowPaging="True" PageSize="5" AllowSorting="True" >

<Columns> <asp:CommandField ButtonType="Button" HeaderText="Actions"

ShowDeleteButton="True" ShowEditButton="True" /> <asp:BoundField DataField="CategoryID" HeaderText="CategoryID"

InsertVisible="False" ReadOnly="True" SortExpression="CategoryID" /> <asp:BoundField DataField="CategoryName" HeaderText="CategoryName"

SortExpression="CategoryName" /> <asp:BoundField DataField="Description" HeaderText="Description"

SortExpression="Description" /> </Columns> </asp:GridView>

Continued…<asp:AccessDataSource ID="AccessDataSource1" runat="server" DataFile="~/App_Data/northwind.mdb" DeleteCommand="DELETE FROM [Categories] WHERE [CategoryID]

= ? AND [CategoryName] = ? AND [Description] = ?" InsertCommand="INSERT INTO [Categories] ([CategoryID], [CategoryName], [Description]) VALUES (?, ?, ?)" SelectCommand="SELECT [CategoryID], [CategoryName], [Description] FROM [Categories]" UpdateCommand="UPDATE [Categories] SET [CategoryName] = ?, [Description] = ? WHERE [CategoryID] =

? AND [CategoryName] = ? AND [Description] = ?" ConflictDetection="CompareAllValues"> <DeleteParameters> <asp:Parameter Name="original_CategoryID" Type="Int32" /> <asp:Parameter Name="original_CategoryName" Type="String" /> <asp:Parameter Name="original_Description" Type="String" /> </DeleteParameters> <UpdateParameters> <asp:Parameter Name="CategoryName" Type="String" /> <asp:Parameter Name="Description" Type="String" /> <asp:Parameter Name="original_CategoryID" Type="Int32" /> <asp:Parameter Name="original_CategoryName" Type="String" /> <asp:Parameter Name="original_Description" Type="String" /> </UpdateParameters> <InsertParameters> <asp:Parameter Name="CategoryID" Type="Int32" /> <asp:Parameter Name="CategoryName" Type="String" /> <asp:Parameter Name="Description" Type="String" /> </InsertParameters> </asp:AccessDataSource> </div> </form></body></html>

Change Description Field to Template Field

Choose Edit Template

Change EditItemTemplate

<asp:TemplateField> for Description <asp:TemplateField HeaderText="Description"

SortExpression="Description"> <ItemTemplate> <asp:Label ID="Label1" runat="server"

Text='<%# Bind("Description") %>'></asp:Label> </ItemTemplate> <EditItemTemplate> <asp:TextBox ID="TextBox1" runat="server"

Text='<%# Bind("Description") %>'></asp:TextBox> </EditItemTemplate></asp:TemplateField>

Change TextBox TextMode Property from SingleLine to MultiLine

CategoryUpdateGridView2.aspx

CategoryProductMasterDetail.aspx

CategoryProductMasterDetail.aspx<%@ Page Language="VB" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"><script runat="server"> Protected Sub DropDownList1_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) LabelCategory.Text = "Category ID selected: " & DropDownList1.SelectedItem.Value LabelCategory.Text &= "<br>Category Name selected: " & DropDownList1.SelectedItem.Text End Sub</script><html xmlns="http://www.w3.org/1999/xhtml" ><head runat="server"> <title>Untitled Page</title></head><body> <form id="form1" runat="server"> <div> <asp:DropDownList ID="DropDownList1" runat="server" AutoPostBack="True"

DataSourceID="AccessDataSource1" DataTextField="CategoryName" DataValueField="CategoryID"

OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged"> </asp:DropDownList><br /> <asp:AccessDataSource ID="AccessDataSource1" runat="server"

DataFile="~/App_Data/northwind.mdb" SelectCommand="SELECT [CategoryID], [CategoryName] FROM

[Categories]"></asp:AccessDataSource> <br /> <asp:Label ID="LabelCategory" runat="server"></asp:Label> </div> </form></body></html>

CatgeoryProductMasterDetail2.aspx

CategoryProductMasterDetail3.aspx

CategoryProductMasterDetail3.aspx<%@ Page Language="VB" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"><script runat="server"></script><html xmlns="http://www.w3.org/1999/xhtml" > <head runat="server"> <title>Untitled Page</title></head><body> <form id="form1" runat="server"> <div>

<asp:DropDownList ID="DropDownList1" runat="server" AutoPostBack="True" DataSourceID="AccessDataSource1"

DataTextField="CategoryName" DataValueField="CategoryID" AppendDataBoundItems=true>AppendDataBoundItems=true>

<asp:ListItem Text="-- Choose a category --" Value="" /><asp:ListItem Text="-- Choose a category --" Value="" /> </asp:DropDownList> <asp:AccessDataSource ID="AccessDataSource1" runat="server"

DataFile="~~/App_Data/northwind.mdb" SelectCommand="SELECT [CategoryID], [CategoryName] FROM

[Categories]" CancelSelectOnNullParameter=false>CancelSelectOnNullParameter=false> </asp:AccessDataSource> <br />

Continued…<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False"

DataKeyNames="ProductID" DataSourceID="AccessDataSource2"> <Columns> <asp:BoundField DataField="ProductID" HeaderText="ProductID"

InsertVisible="False" ReadOnly="True" /> <asp:BoundField DataField="ProductName" HeaderText="ProductName" /> <asp:BoundField DataField="SupplierID" HeaderText="SupplierID" /> <asp:BoundField DataField="UnitPrice" HeaderText="UnitPrice" /> <asp:BoundField DataField="UnitsInStock" HeaderText="UnitsInStock" /> <asp:CheckBoxField DataField="Discontinued" HeaderText="Discontinued" /> </Columns> </asp:GridView> <asp:AccessDataSource ID="AccessDataSource2" runat="server"

DataFile="~~/App_Data/northwind.mdb" SelectCommand="SELECT [ProductID], [ProductName], [SupplierID], [UnitPrice],

[UnitsInStock], [Discontinued] FROM [Products] WHERE ([CategoryID] = ?)"> <SelectParameters> <asp:ControlParameter ControlID="DropDownList1" Name="CategoryID"

PropertyName="SelectedValue" Type="Int32" /> </SelectParameters> </asp:AccessDataSource> </div> </form></body></html>

ManageProduct.aspx

Add Edit and New Button

3Make sure that Insert, Update, Delete statements are generated

Insert Problem• Using Visual Web Developer 2005 and ASP.NET 2.0

• If you insert an AccessDataSource that use a table for insert, update and delete operations and the table has a primary key that is an autonumber, the code that is generated is shown in the next 3 slides.

• If you want to insert a record (Using a DetailsView object) you get the following error: "You tried to assign the Null value to a variable that is not a Variant data type." .

• To correct the problem, remove the highlighted (Bold & UnderlinedBold & Underlined) code that has been generated.

Source: http://forums.asp.net/1027200/ShowPost.aspx

ManageProduct.aspx<%@ Page Language="VB" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"><script runat="server"></script><html xmlns="http://www.w3.org/1999/xhtml" ><head runat="server"><title>Untitled Page</title></head><body> <form id="form1" runat="server"> <div> <strong>Manage Product Information<br /> </strong> <asp:DetailsView ID="DetailsView1" runat="server" AllowPaging="True" AutoGenerateRows="False" DataKeyNames="ProductID" DataSourceID="AccessDataSource1" Height="50px" > <PagerSettings Mode="NextPreviousFirstLast" /> <Fields> <asp:BoundField DataField="ProductID" HeaderText="ProductID" InsertVisible="False" ReadOnly="True" SortExpression="ProductID" /> <asp:BoundField DataField="ProductName" HeaderText="ProductName" SortExpression="ProductName" /> <asp:BoundField DataField="CategoryID" HeaderText="CategoryID" SortExpression="CategoryID" /> <asp:BoundField DataField="UnitPrice" HeaderText="UnitPrice" SortExpression="UnitPrice" /> <asp:CheckBoxField DataField="Discontinued" HeaderText="Discontinued" SortExpression="Discontinued" /> <asp:BoundField DataField="SupplierID" HeaderText="SupplierID" /> <asp:BoundField DataField="QuantityPerUnit" HeaderText="QuantityPerUnit" /> <asp:BoundField DataField="UnitsInStock" HeaderText="UnitsInStock" SortExpression="UnitsInStock" /> <asp:BoundField DataField="UnitsOnOrder" HeaderText="UnitsOnOrder" SortExpression="UnitsOnOrder" /> <asp:BoundField DataField="ReorderLevel" HeaderText="ReorderLevel" />

<asp:CommandField ShowDeleteButton="True" ShowEditButton="True" ShowInsertButton="True" />

</Fields> </asp:DetailsView>

Continued…<asp:AccessDataSource ID="AccessDataSource1" runat="server"

DataFile="~/App_Data/northwind.mdb" DeleteCommand="DELETE FROM [Products] WHERE [ProductID] = ?"

InsertCommand="INSERT INTO [Products]

( [ProductID], [ProductID], [ProductName], [CategoryID], [UnitPrice], [Discontinued], [SupplierID], [QuantityPerUnit], [UnitsInStock], [UnitsOnOrder], [ReorderLevel])

VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)" SelectCommand="SELECT [ProductID], [ProductName], [CategoryID],

[UnitPrice], [Discontinued], [SupplierID], [QuantityPerUnit], [UnitsInStock], [UnitsOnOrder], [ReorderLevel] FROM [Products]"

UpdateCommand="UPDATE [Products] SET [ProductName] = ?, [CategoryID] = ?, [UnitPrice] = ?, [Discontinued] = ?, [SupplierID] = ?,

[QuantityPerUnit] = ?, [UnitsInStock] = ?, [UnitsOnOrder] = ?, [ReorderLevel] = ? WHERE [ProductID] = ?"> <DeleteParameters> <asp:Parameter Name="original_ProductID" Type="Int32" /> </DeleteParameters>

Continued…<UpdateParameters> <asp:Parameter Name="ProductName" Type="String" /> <asp:Parameter Name="CategoryID" Type="Int32" /> <asp:Parameter Name="UnitPrice" Type="Decimal" /> <asp:Parameter Name="Discontinued" Type="Boolean" /> <asp:Parameter Name="SupplierID" Type="Int32" /> <asp:Parameter Name="QuantityPerUnit" Type="String" /> <asp:Parameter Name="UnitsInStock" Type="Int16" /> <asp:Parameter Name="UnitsOnOrder" Type="Int16" /> <asp:Parameter Name="ReorderLevel" Type="Int16" /> <asp:Parameter Name="original_ProductID" Type="Int32" /> </UpdateParameters> <InsertParameters>

<asp:Parameter Name="ProductID" Type="Int32" /><asp:Parameter Name="ProductID" Type="Int32" /> <asp:Parameter Name="ProductName" Type="String" /> <asp:Parameter Name="CategoryID" Type="Int32" /> <asp:Parameter Name="UnitPrice" Type="Decimal" /> <asp:Parameter Name="Discontinued" Type="Boolean" /> <asp:Parameter Name="SupplierID" Type="Int32" /> <asp:Parameter Name="QuantityPerUnit" Type="String" /> <asp:Parameter Name="UnitsInStock" Type="Int16" /> <asp:Parameter Name="UnitsOnOrder" Type="Int16" /> <asp:Parameter Name="ReorderLevel" Type="Int16" /> </InsertParameters> </asp:AccessDataSource> <asp:Label ID="Label1" runat="server" Text="Label"></asp:Label> </div> </form></body></html>

Delete!!!

Data Binding In Templates

• Goal: Simpler data expression syntax for both simple and complex expressions

• V1 Databinding syntax– <%# DataBinder.Eval(Container.DataItem, "field" [, formatString]) %>

• New Syntax– <%# Eval("field") %> // one-way databinding

– <%# Bind("field") %> // two-way databinding

Data Binding in Templates

• Two-way data bindings – Enable templated controls to retrieve input

values to use as parameters

– Allow templated controls to perform automatic updates/deletes

– GridView and DetailsView both support two-way data bindings using TemplateField

– New FormView control allows completely templated rendering of DetailsView

– Future ListView control would provide this behavior for DataList functionality

Use Template for Editing CategoryID

CategoryID Template …..<asp:BoundField DataField="ProductName"

HeaderText="ProductName" SortExpression="ProductName" /> <asp:TemplateField HeaderText="CategoryID"> <ItemTemplate> <asp:Label ID="Label1" runat="server"

Text='<%# Bind("CategoryID") %>'></asp:Label> </ItemTemplate> <EditItemTemplate> <asp:TextBox ID="TextBox1" runat="server"

Text='<%# Bind("CategoryID") %>'></asp:TextBox> </EditItemTemplate> <InsertItemTemplate> <asp:TextBox ID="TextBox1" runat="server"

Text='<%# Bind("CategoryID") %>'></asp:TextBox> </InsertItemTemplate> </asp:TemplateField> <asp:BoundField DataField="UnitPrice" HeaderText="UnitPrice"

SortExpression="UnitPrice" />…..

Set SelectedValue Properties

Modified Template <asp:TemplateField HeaderText="CategoryID"> <ItemTemplate> <asp:Label ID="Label1" runat="server" Text='<%# Bind("CategoryID") %>'></asp:Label>

</ItemTemplate> <EditItemTemplate> <asp:DropDownList ID="DropDownList1" runat="server"

DataSourceID="AccessDataSource1" DataTextField="CategoryName" DataValueField="CategoryID"

SelectedValue='<%# Bind("CategoryID") %>'> </asp:DropDownList>

<asp:AccessDataSource ID="AccessDataSource1" runat="server" DataFile="~/App_Data/northwind.mdb"

SelectCommand="SELECT [CategoryID], [CategoryName] FROM [Categories]">

</asp:AccessDataSource> </EditItemTemplate> <InsertItemTemplate> <asp:TextBox ID="TextBox1" runat="server" Text='<%#

Bind("CategoryID") %>'></asp:TextBox> </InsertItemTemplate></asp:TemplateField>

Indirect Events

• Indirect events can be raised by ASP.NET internally because of some action taken by the user.

DeletingDeleting

Is deleting allowed

Cancel the evente.Cancel = True

DeletedDeleted

Yes Run the event' Handle exception gracefullyIf e.Exception IsNot Nothing Then

AccessDataSource1_DeletedAccessDataSource1_Deleting

Handle Exception (Partial Code)<%@ Page language="VB" %><script runat="server"> Sub CustomersGridView_RowDeleted(ByVal sender As Object, ByVal e As GridViewDeletedEventArgs) ' Use the Exception property to determine whether an exception ' occurred during the delete operation. If e.Exception Is Nothing Then ' Use the AffectedRows property to determine whether the ' record was deleted. Sometimes an error might occur that ' does not raise an exception, but prevents the delete ' operation from completing. If e.AffectedRows = 1 Then Message.Text = "Record deleted successfully." Else Message.Text = "An error occurred during the delete operation." End If Else ' Insert the code to handle the exception. Message.Text = "An error occurred during the delete operation." ' Use the ExceptionHandled property to indicate that the ' exception is already handled. e.ExceptionHandled = True End If End Sub</script>

<html> <body> <form runat="server"> <h3>GridViewDeletedEventArgs Example</h3> <asp:label id="Message" forecolor="Red" runat="server"/> <br/>

<asp:gridview id="CustomersGridView"

datasourceid="CustomersSqlDataSource" autogeneratecolumns="true"

autogeneratedeletebutton="true" datakeynames="CustomerID"

onrowdeleted="CustomersGridView_RowDeleted" runat="server">

</asp:gridview>    <asp:sqldatasource id="CustomersSqlDataSource" selectcommand="Select [CustomerID], [CompanyName], [Address], [City],

[PostalCode], [Country] From [Customers]" deletecommand="Delete from Customers where CustomerID = @CustomerID" connectionstring = "<%$ ConnectionStrings:NorthWindConnectionString%>" runat="server"> </asp:sqldatasource> </form> </body></html>

Insert Issues

• Not pass an identity column during an insert to the database?

– Set InsertVisible property of control to false

• After the insert, retrieve the newly inserted record, complete with identity column?

– Uses Inserted event of DataSource control and grab the value of the identity column using e.Command.Parameters collection

Insert, Update, Delete Issues – Keep Controls in Sync

• Refresh one control when another changes?• Call DataBind() method of second control from

first control’s ItemInserted,ItemUpdated, or ItemDeleted event

Protected Sub FormView1_ItemInserted(ByVal sender As Object, _ ByVal e As System.Web.UI.WebControls.FormViewInsertedEventArgs)

If e.Exception IsNot Nothing Then LabelMsg.Text = "Insert failed. Reason: " & e.Exception.Message

Else LabelMsg.Text = "Insert succeeded!" FormView1.Visible = False

GridView1.DataBind() End If End Sub

Set a default value of a control for an insert

• Use DataBound event, checking the CurrentMode property

Protected Sub FormView1_DataBound(ByVal sender As Object, _

ByVal e As System.EventArgs)

' Set default value of the supplier ID to the current supplier ID

If (FormView1.CurrentMode = FormViewMode.Insert) Then CType(FormView1.FindControl("SUPIDLabel"), Label).Text = _

LabelSupplierID.Text

End If

End Sub

data-driven - 1 © minder chen, 2002-2007 building data-driven web sites in asp.net 2.0

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