RSS Feed (xml)
Use the System.Web.UI.WebControls.ListBox control to place a ListBox control.To
allow multiple values to be chosen from the ListBox, set the SelectionMode property to
Multiple.The default is Single.The SelectedIndex property can use used to determine
whether the user has selected any items from the ListBox.The ASPX page is as
follows:
<html>
<head>
<title>code0111vb</title>
</head>
<body>
<form id=”Form1” method=”post” runat=”server”>
<asp:ListBox
ID=”CountryListBox”
Runat=”server”
SelectionMode=”Multiple”>
<asp:ListItem Value=1>United States</asp:ListItem>
<asp:ListItem Value=2>United Kingdom</asp:ListItem>
<asp:ListItem Value=3>China</asp:ListItem>
<asp:ListItem Value=4>India</asp:ListItem>
</asp:ListBox><br>
<asp:Button
ID=”SubmitButton”
Runat=”server”
Text=”Submit”
OnClick=”Verify”>
</asp:Button>
<asp:Label
ID=”OutputLabel”
Runat=”server”>
</asp:Label>
</form>
</body>
</html>
In <script runat=”server” /> block or codebehind:
Public Sub Verify(sender As System.Object, e As System.EventArgs)
Dim myListItem As ListItem
If CountryListBox.SelectedIndex <> -1 Then
OutputLabel.Text = “You selected: “
If CountryListBox.SelectionMode = ListSelectionMode.Single Then
OutputLabel.Text += “<b>” & _
CountryListBox.SelectedItem.Text & “</b>”
Else
For Each myListItem In CountryListBox.Items
If myListItem.Selected Then
OutputLabel.Text += “<b>” & myListItem.Text & _
“</b>, “
End If
Next
End If
Else
OutputLabel.Text = “You didn’t selected any country!”
End If
End Sub
This example demonstrates how to determine which values a user selected from a multiple-
selection ListBox. First, you start with an If statement, which verifies whether the
user has selected an item.Then you parse through all the items in the ListBox to find the
number of items selected.You also use a LabelWeb Server Control to display the output
to the user. If you want to retrieve the value of the selected item, you use the following
statement:
CountryListBox.SelectedItem.Value
Note that for a multiple-selection ListBox, this will only return the first value.
Archives
-
▼
2008
(100)
-
▼
September
(72)
- You can stream the binary data returned by SQL Ser...
- Inserting an Image into SQL Server
- Executing a Stored Procedure with No Results Returned
- Using a Tool to Create a Data Access Layer
- Using Microsoft’s Data Access Application
- Connecting to an ODBC Datasource
- Connecting to MySQL Database
- Connecting to a Microsoft Access Database
- Connecting to Oracle
- Connecting to SQL Server
- Catching Exceptions
- Handling Page Level Errors
- Raising Exceptions
- Enabling Page Level Tracing
- Logging Error Details
- Configuring a Default Error Page in ASP.NET
- Perform Custom Authentication on Each Request
- Creating a Simple Forms Authentication Logout Page
- Creating a Simple Forms Authentication Login Page
- Requiring Authentication to Access Files and Folders
- Configuring Windows Authentication
- Configuring Forms Authentication
- Reading and Storing Data in ViewState
- Reading and Storing Data in Cookies
- Reading and Writing Values to the Session Object
- Reading and Writing Values to the Application Object
- Configuring Sessions in your ASP.NET Application
- Configuring Application Error Handling
- Configuring Application Debugging
- Configuring Application Tracing
- Creating Custom Application Settings in the web.co...
- Storing and Reading Custom Settings from the web.c...
- Customizing Output for a Device
- Displaying ObjectList Information in a Table
- Configuring Automatic Paging of Content
- Navigation in a Mobile Web Form
- Creating a Mobile Web Form
- Implementing a CallBack when a Cached
- Using HttpContext for Per-Request Caching
- Varying Output Caching by HTTP Headers
- Varying Output Caching by Browser
- Varying Output Caching by Parameter(s)
- Creating a Cache Dependency
- Retrieving Data from the Cache
- Inserting Data into the Cache
- Partial Page Output Caching Using VaryByControl
- Page Output Caching
- Installing a Component in the Global Assembly Cach...
- Data-binding a TreeView Control
- Using the ToolBar IE Web Control
- Using the TabControl and PageView IE Web Controls
- Dynamically Adding Controls to a Web Form
- Creating a Templated Control
- Creating a Data-bound Control
- Creating a Composite Control
- Creating ViewState-Enabled Control Properties
- Extending Existing Web Controls
- Declaring a Simple Custom Control
- Programmatically Accessing Properties of a Late-Bo...
- Sharing User Controls Across Application Domains
- Raising Events from a User Control
- Dynamically Adding User Controls to a Web Form
- Partial Page Output Caching in ASP.NET
- Dynamically Adding User Controls to a Web Form in ...
- Getting and Setting User Control Properties in ASP...
- Adding a User Control to a Web Form in ASP.NET
- Declaring a User Control in ASP.NET
- Adding Client-Side Script to a Web Form in ASP.NET
- Persisting Data on a Web Form between Postbacks in...
- Working with ListBoxes in ASP.NET
- Creating Dependent DropDownList Controls in ASP.NET
- Working With DropDownLists in ASP.NET
-
▼
September
(72)
No comments:
Post a Comment