Build Your Own ASP.NET 2.0 Web Site Using C# & VB, Second Edition

Figure 11.17. The DetailsView’s BoundFields have been converted

to TemplateFields

Updating DetailsView Records

Now that you have your DetailsView control in place, let’s complete its func-

tionality by making the Update link functional. To begin, we’ll generate the

ItemUpdating event handler. The ItemUpdating event is triggered when the

Update link is clicked—an action that will occur once the user enters new data

into the text boxes and is ready to commit the updated data to the database.

Open AddressBook.aspx in the designer, select the DetailsView control, and

switch to the events viewer by clicking the Event button (the little lightning

symbol) in the Properties window. There, double-click the ItemUpdating row to

have the designer generate the employeeDetails_ItemUpdating method for you,

and update the handler with the code shown below:

Visual Basic File: AddressBook.aspx.vb (excerpt)

Protected Sub employeeDetails_ItemUpdating( _

ByVal sender As Object, ByVal e As _

System.Web.UI.WebControls.DetailsViewUpdateEventArgs) _

Handles employeeDetails.ItemUpdating

' Read the employee ID from the DetailsView object

Dim employeeId As Integer = employeeDetails.DataKey.Value

' Find the TextBox controls with updated data

Dim newAddressTextBox As TextBox = _

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Updating DetailsView Records

employeeDetails.FindControl("editAddressTextBox")

Dim newCityTextBox As TextBox = _

employeeDetails.FindControl("editCityTextBox")

' Extract the updated data from the TextBoxes

Dim newAddress As String = newAddressTextBox.Text

Dim newCity As String = newCityTextBox.Text

' Declare data objects

Dim conn As SqlConnection

Dim comm As SqlCommand

' Read the connection string from Web.config

Dim connectionString As String = _

ConfigurationManager.ConnectionStrings( _

"Dorknozzle").ConnectionString

' Initialize connection

conn = New SqlConnection(connectionString)

' Create command

comm = New SqlCommand("UpdateEmployeeDetails", conn)

comm.CommandType = Data.CommandType.StoredProcedure

' Add command parameters

comm.Parameters.Add("@EmployeeID", Data.SqlDbType.Int)

comm.Parameters("@EmployeeID").Value = employeeId

comm.Parameters.Add("@NewAddress", Data.SqlDbType.NVarChar, 50)

comm.Parameters("@NewAddress").Value = newAddress

comm.Parameters.Add("@NewCity", Data.SqlDbType.NVarChar, 50)

comm.Parameters("@NewCity").Value = newCity

' Enclose database code in Try-Catch-Finally

Try

' Open the connection

conn.Open()

' Execute the command

comm.ExecuteNonQuery()

Finally

' Close the connection

conn.Close()

End Try

' Exit edit mode

employeeDetails.ChangeMode(DetailsViewMode.ReadOnly)

' Reload the employees grid

BindGrid()

' Reload the details view

BindDetails()

End Sub

C# File: AddressBook.aspx.cs (excerpt)

protected void employeeDetails_ItemUpdating(object sender,

DetailsViewUpdateEventArgs e)

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Chapter 11: Managing Content Using Grid View and Details View

{

// Read the employee from the DetailsView object

int employeeId = (int)employeeDetails.DataKey.Value;

// Find the TextBox controls with updated data

TextBox newAddressTextBox =

(TextBox)employeeDetails.FindControl("editAddressTextBox");

TextBox newCityTextBox =

(TextBox)employeeDetails.FindControl("editCityTextBox");

// Extract the updated data from the TextBoxes

string newAddress = newAddressTextBox.Text;

string newCity = newCityTextBox.Text;

// Define data objects

SqlConnection conn;

SqlCommand comm;

// Initialize connection

string connectionString =

ConfigurationManager.ConnectionStrings[

"Dorknozzle"].ConnectionString;

// Initialize connection

conn = new SqlConnection(connectionString);

// Create command

comm = new SqlCommand("UpdateEmployeeDetails", conn);

comm.CommandType = CommandType.StoredProcedure;

// Add command parameters

comm.Parameters.Add("EmployeeID", SqlDbType.Int);

comm.Parameters["EmployeeID"].Value = employeeId;

comm.Parameters.Add("NewAddress", SqlDbType.NVarChar, 50);

comm.Parameters["NewAddress"].Value = newAddress;

comm.Parameters.Add("NewCity", SqlDbType.NVarChar, 50);

comm.Parameters["NewCity"].Value = newCity;

// Enclose database code in Try-Catch-Finally

try

{

// Open the connection

conn.Open();

// Execute the command

comm.ExecuteNonQuery();

}

finally

{

// Close the connection

conn.Close();

}

// Exit edit mode

employeeDetails.ChangeMode(DetailsViewMode.ReadOnly);

// Reload the employees grid

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Updating DetailsView Records

BindGrid();

// Reload the details view

BindDetails();

}

This code is pretty straightforward. It starts by reading the value of the DataKey

of the DetailsView object. As we saw earlier, the DetailsView, like the GridView,

is able to store the ID of the record (or records) it’s displaying. You’ll remember

that we made the DetailsView object aware of the EmployeeID data key when

we bound the DetailsView to its data source in the BindDetails method. We

read this information in the ItemUpdating event handler, like so:

Visual Basic File: AddressBook.aspx.vb (excerpt)

' Read the employee from the DetailsView object

Dim employeeId As Integer = employeeDetails.DataKey.Value

C# File: AddressBook.aspx.cs (excerpt)

// Read the employee from the DetailsView object

int employeeId = (int) employeeDetails.DataKey.Value;

The next step is to find the TextBox objects that contain the updated data. We

do this using the FindControl method, as we’ve seen previously. After we obtain

the control references, we obtain the string values that we’re interested in simply

by reading their Text properties, as is shown in the following code snippets:

Visual Basic File: AddressBook.aspx.vb (excerpt)

' Find the TextBox controls with updated data

Dim newAddressTextBox As TextBox = _

employeeDetails.FindControl("editAddressTextBox")

Dim newCityTextBox As TextBox = _

employeeDetails.FindControl("editCityTextBox")

' Extract the updated data from the TextBoxes

Dim newAddress As String = newAddressTextBox.Text

Dim newCity As String = newCityTextBox.Text

C# File: AddressBook.aspx.cs (excerpt)

// Find the TextBox controls with updated data

TextBox newAddressTextBox =

(TextBox)employeeDetails.FindControl("editAddressTextBox");

TextBox newCityTextBox =

(TextBox)employeeDetails.FindControl("editCityTextBox");

// Extract the updated data from the TextBoxes

string newAddress = newAddressTextBox.Text;

string newCity = newCityTextBox.Text;

466

Chapter 11: Managing Content Using Grid View and Details View