RadioButton and CheckBox in VS .NET

Create Code 128 Code Set C in VS .NET RadioButton and CheckBox
RadioButton and CheckBox
Code 128 Recognizer In Visual Studio .NET
Using Barcode Control SDK for .NET framework Control to generate, create, read, scan barcode image in VS .NET applications.
CheckedChanged Checked
Printing ANSI/AIM Code 128 In .NET Framework
Using Barcode creation for .NET Control to generate, create Code 128 image in .NET framework applications.
RadioButtonList, CheckBoxList,ListBox, andDropDownList
Code128 Recognizer In .NET Framework
Using Barcode decoder for VS .NET Control to read, scan read, scan image in .NET framework applications.
SelectedIndexChanged
Painting Bar Code In .NET
Using Barcode generation for VS .NET Control to generate, create bar code image in .NET applications.
Button, LinkButton, and ImageButton
Recognize Barcode In Visual Studio .NET
Using Barcode reader for VS .NET Control to read, scan read, scan image in Visual Studio .NET applications.
Click
Generating USS Code 128 In C#
Using Barcode generator for Visual Studio .NET Control to generate, create USS Code 128 image in VS .NET applications.
Table 3-12: Events associated with ASP.NET server controls Control(s) Event Description submitted to the server. By default, only the Click event of the Button, LinkButton, and ImageButton server controls causes the form to be submitted to the server for processing the form is said to be posted back to the server. The Change events associated with other controls are captured and cached and do not cause the form to be submitted immediately. When the form is posted back (as a result of a button click), all the pending events are raised and processed. No particular sequence exists for processing these Change events, such as TextChanged and CheckChanged on the server. The Click event is processed only after all the Change events are processed. You can set the change events of server controls to result in the form post back to the server. To do so, modify the AutoPostBack property to True. Event handlers When the events are raised, you need to handle them for processing. The procedures that are executed when an event occurs are called event handlers. An event handler is associated with the corresponding event by using the WithEvents and Handles keywords. The WithEvents keyword is used to declare the control generating an event. For example, when you declare a control, say Image1 as 'Protected WithEvents Image1 As System.Web.UI.WebControls.Image', the WithEvents keyword specifies that Image1 is an object variable used to respond to events raised by the instance assigned to the variable. The Handles keyword is used to associate the event handler with the event, which is raised by the control. The control in turn is declared by using the WithEvents keywords. Event handlers are automatically created when you double-click the control in Design mode of the form. For example, the following code is generated when you double-click a Button control whose ID is RegisterButton. You can then write the code in the event handler to perform the intended task. Public Sub RegisterButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles RegisterButton.Click End Sub In this code: The procedure RegisterButton_Click is the event handler for the Click event of the button with ID RegisterButton. The Handles keyword associates the event with the event handler. The procedure takes two arguments. The first argument contains the event sender. An event sender is an object, such as a form or a control, that can generate events. The second argument contains the event data. Implementing the events and event handlers After discussing the events and event handlers in detail, we'll now implement them for the Web Forms page shown in Figure 3-3, earlier in the chapter. In Figure 3-3, when you click the Register button, another page should open displaying a relevant message along with the username entered in the UserName TextBox control. Before you can proceed to write the event handlers, you need to add another Web Forms page (the target page) to the Application project. To do so: 1. Select Project Add Web Form. The Add New Item dialog box opens. 2. Specify the name of the Web Forms page and click Open. In this case, leave the default name of the Web Forms page, WebForm2.aspx.
Code128 Drawer In .NET Framework
Using Barcode creation for ASP.NET Control to generate, create Code 128 Code Set B image in ASP.NET applications.
When you add a Web Forms page to a project, the name of the Web Forms page automatically takes the next number. For example, if WebForm1 already exists in the project, the default name of the new Web Forms page would be WebForm2. Because the target page (WebForm2) should display a message, you need to add a Label control to this page. Set the ID property of this Label control to MessageLabel. To implement this functionality, you need to write the following code in the Click event of the Register button (in the WebForm1 page): Tip Response.Redirect("WebForm2.aspx strTextValue=" & "Hi," & UserName.Text & ", You have been successfully registered") In this code, the Response.Redirect method takes the URL of the target page. The URL specifies another form named WebForm2.aspx (that you added) and passes a text string along with the value in the TextBox control whose ID is UserName in a variable called strTextValue. After passing the text in the strTextValue variable, the Label control in the target form, WebForm2, must be initialized in the Init procedure of the form as follows: MessageLabel.Text = Request.QueryString("strTextValue") In this code, the value stored in the strTextValue is set as the caption of the label with ID MessageLabel in WebForm2. The Web Forms page displayed in Figure 3-3 also contains a Reset button. When you click the Reset button, all the controls should be empty. To implement this functionality, use the following code: UserName.Text = "" Email.Text = "" USStateList.ClearSelection() SexOption.ClearSelection() SubscriptionOptions.ClearSelection() In this code: The Text property of the TextBox controls with IDs UserName and Email are set to a null value. ClearSelection is a method of the list controls, such as ListBox, DropDownList, CheckBoxList, and RadioButtonList controls. The method is used to clear any selection made in the list. Handling post back As mentioned earlier, the Web Forms page is posted back to the server only when a Button, LinkButton, or ImageButton ASP.NET server control is clicked. After the page is posted to the server, it is processed there. You can respond to a button event in one of the following ways: Write an event handler for the Click event of the button. Write the event handler for the Load event of the Web Forms page. The Load event is generated when the form is loaded from the server to the client (browser). You can use the IsPostBack property in the Load event to determine whether the page has been processed for the first time or by a button click. To understand the IsPostBack property better, consider the following code in the Page_Load event of the WebForm1 page. The following code checks whether the IsPostBack property is True. If it is, the Visible property of the Register button is set to False. As System.EventArgs) Handles MyBase.Load Private Sub Page_Load(ByVal sender As System.Object, ByVal e
Paint USS Code 128 In Visual Basic .NET
Using Barcode printer for .NET framework Control to generate, create Code 128 Code Set A image in .NET framework applications.
UCC.EAN - 128 Creator In .NET
Using Barcode maker for .NET Control to generate, create UCC-128 image in .NET framework applications.
Code 128 Code Set B Creator In Visual Studio .NET
Using Barcode printer for VS .NET Control to generate, create Code-128 image in Visual Studio .NET applications.
Barcode Decoder In Java
Using Barcode reader for Java Control to read, scan read, scan image in Java applications.
Data Matrix Drawer In Visual Studio .NET
Using Barcode generator for ASP.NET Control to generate, create DataMatrix image in ASP.NET applications.
Draw ECC200 In Visual Basic .NET
Using Barcode generation for Visual Studio .NET Control to generate, create Data Matrix image in .NET applications.
Drawing Code 128 Code Set C In Visual C#.NET
Using Barcode maker for VS .NET Control to generate, create Code128 image in VS .NET applications.