Tài liệu Hyperlink from a Row in the Data Grid to a Detail Page ppt

5.8 Hyperlink from a Row in the Data Grid to a Detail Page Often, I need to zero in and display data based on a record in the DataGrid control.. Technique One of the types of columns th

5.8 Hyperlink from a Row in the Data Grid to a Detail Page

Often, I need to zero in and display data based on a record in the DataGrid control How

do I display detail information in a separate page from a DataGrid control?

Technique

One of the types of columns that you can use in the data grid is the HyperLink column This column makes it fairly easy to link pages based on data To see how the HyperLink type column is used in this How-To, take a look at Figure 5.14

Figure 5.14 No code is required for link pages based on data

By your specifying the URL Field to be ProductID and URL Format String to be

wfrmHowTo5_8b.aspx?ID={0}, the data grid automatically calls the

wfrmHowTo5_8b.aspx and passes the ProductID to the form when you click on a

product

Steps

Open and run the Visual Basic NET-Chapter 5 solution From the main page, click on the hyperlink with the caption How-To 5.8: Hyperlink From a Row in the Data Grid to a Detail Page You then see all the products loaded into a data grid Notice that the

products are actually hyperlinks (see Figure 5.15)

Figure 5.15 These hyperlinks require no code to call a detail page

When you click on a product, another page is displayed, with detail information supplied (see Figure 5.16)

1 Create a Web Form Then place the controls in Table 5.12 and Figure 5.15 with the following properties set

Table 5.12 Property Settings for the Controls Used on the First Page of This

How-To

OleDbDataAdapter ID odaProducts

SelectCommand SELECT ProductID, ProductName

FROM Products

DataGrid ID dgProducts

2 Right-click on the DataGrid control and choose Property Builder Click on the Columns tab and set the properties as displayed in Figure 5.14 Be sure to note the name of the form you are calling in the URL Format String so that you can name it the same in step 4

3 Add the code in Listing 5.30 to the Load event of the page

Listing 5.30 wfrmHowTo5_8a.aspx.vb: Filling and Binding the Products to the DataGrid Object

Private Sub Page_Load(ByVal sender As System.Object,

ByVal e As System.EventArgs) Handles MyBase.Load

'Put user code to initialize the page here

odaProducts.Fill(DsProducts)

dgProducts.DataBind()

End Sub

4 Create another Web Form Then place the controls in Table 5.13 and Figure 5.16 with the following properties set

Table 5.13 Property Settings for the Controls Used on the Second Page of

This How-To Object Property Setting

5 Add the code in Listing 5.31 to the Load event of the page In the SQL select statement created in this listing, the Request.Item is used to grab the productID that was passed from the first form The dtProdIndiv data table is filled, and the individual column information is loaded into the text boxes

Listing 5.31 wfrmHowTo5_8b.aspx.vb: Loading the Detail Information Based

on the ProductID

Private Sub Page_Load(ByVal sender As System.Object,

ByVal e As System.EventArgs) Handles MyBase.Load

'Put user code to initialize the page here

Dim odaProdIndiv As OleDb.OleDbDataAdapter

odaProdIndiv = New _

OleDb.OleDbDataAdapter(_

"Select * From Products Where ProductID = " &

Request.Item("ID"), BuildCnnStr("(local)", "Northwind"))

Dim dtProdIndiv As New DataTable()

odaProdIndiv.Fill(dtProdIndiv)

With dtProdIndiv.Rows(0)

Me.txtProductName.Text = Item("ProductName")

Me.txtUnitPrice.Text = Item("UnitPrice")

End With

End Sub

Figure 5.16 You will use the request object in code on this page to retrieve detail

data

Comments

That's it! A good way to expand this example is to add the coding technique learned in the previous How-To for editing data

Using data with your Web Forms is not much harder than using Windows Forms Just remember to stash some variables for round trips to the server and to bind your data