Introduction and Demonstration
Selection controls allow the user to select one or more values from a list. They
include both the CheckBox and RadioButton controls, which are designed to work
in a group. The RadioButton control allows you to select only one option out of
the group, whereas the CheckBox control allows you to select zero or more
options.
| Control | Purpose |
| CheckBox | Selects or unselects an option. You can toggle the selection. |
| RadioButton | Selects only one option out of a group. You can unselect an option only by selecting another RadioButton control in the group. |
| ListBox | Allows the user to select one or more options from a list represented by ListItem controls. This control always occupies a fixed space in the form. |
| DropDownList | Allows the user to select only one option out of a list represented by ListItem controls. This control is used where the space in the form is limited. |
| RadioButtonList | Presents a list of radio buttons represented by ListItem controls and allows selection of only one option. |
| CheckBoxList | Presents a list of checkboxes represented by ListItem controls and allows you to select zero or more of the options. |
The simplified syntax of the selection controls
is as follows:
<asp:checkbox id="MyCheckBox1"
text="Vanilla" runat="server"/>
<asp:checkbox id="MyCheckBox2"
text="Chocolate" runat="server"/>
<asp:radiobutton id="MyRadioButton1" groupname="Group1"
checked="True" text="Yes" runat="Server"/>
<asp:radiobutton id="MyRadioButton2" groupname="Group1"
text="No" runat="Server"/>
<asp:listbox id="MyListBox" runat="server">
<asp:listitem value="Vanilla" selected="true">Vanilla</asp:listitem>
<asp:listitem value="Chocolate">Chocolate</asp:listitem>
<asp:listitem value="Strawberry">Strawberry</asp:listitem>
</asp:listbox>
<asp:dropdownlist id="MyDropDownList" runat="server">
<asp:listitem value="Single" selected="true">Single</asp:listitem>
<asp:listitem value="Multiline">Multiline</asp:listitem>
<asp:listitem value="Password">Password</asp:listitem>
</asp:dropdownlist>
<asp:checkboxlist id="MyCheckBoxList"
repeatdirection="vertical" runat="server">
<asp:listitem value="Vanilla" text="Vanilla"/>
<asp:listitem value="Chocolate" text="Chocolate"/>
<asp:listitem value="Strawberry" text="Strawberry"/>
</asp:checkboxlist>
<asp:radiobuttonlist id="MyRadioButtonList"
repeatdirection="Horizontal" runat="server">
<asp:listitem value="Female" text="Female" selected="true"/>
<asp:listitem value="Male" text="Male"/>
</asp:radiobuttonlist>
The controls can then be referenced programmatically with code fragments like
the following:
MyCheckBox1.Checked
= True
MyRadioButton1.Checked = False
MyListBox.SelectionMode = ListSelectionMode.Multiple
MyDropDownList.SelectedIndex = 1
MyCheckBoxList.RepeatDirection = RepeatDirection.Horizontal
MyRadioButtonList.RepeatLayout = RepeatLayout.Table
Index.aspx Page
<%@ Page Language="vb" %>
<html>
<head>
<title>Selection
Control Example</title>
<script runat="server">
Sub Page_Load( )
MyCheckBox1.Checked = True
MyRadioButton1.Checked = False
MyListBox.SelectionMode = ListSelectionMode.Multiple
MyDropDownList.SelectedIndex = 1
MyCheckBoxList.RepeatDirection = RepeatDirection.Horizontal
MyRadioButtonList.RepeatLayout = RepeatLayout.Table
End Sub
</script>
</head>
<body>
<h1>Selection
Control Example</h1>
<form id="Form1" runat="server">
<asp:table id="MyTable"
border="1"
cellpadding="5"
cellspacing="0"
runat="server">
<asp:tablerow ID="Tablerow1" runat="server">
<asp:tablecell ID="Tablecell1" runat="server">
CheckBox Control:
</asp:tablecell>
<asp:tablecell ID="Tablecell2" runat="server">
<asp:checkbox id="MyCheckBox1"
text="Vanilla" runat="server" />
<asp:checkbox id="MyCheckBox2"
text="Chocolate" runat="server" />
</asp:tablecell>
</asp:tablerow>
<asp:tablerow ID="Tablerow2" runat="server">
<asp:tablecell ID="Tablecell3" runat="server">
RadioButton Control:
</asp:tablecell>
<asp:tablecell ID="Tablecell4" runat="server">
<asp:radiobutton id="MyRadioButton1" groupname="Group1"
checked="True" text="Yes" runat="Server"/>
<asp:radiobutton id="MyRadioButton2" groupname="Group1"
text="No" runat="Server"/>
</asp:tablecell>
</asp:tablerow>
<asp:tablerow ID="Tablerow3" runat="server">
<asp:tablecell ID="Tablecell5" runat="server">
ListBox Control:
</asp:tablecell>
<asp:tablecell ID="Tablecell6" runat="server">
<asp:listbox id="MyListBox" runat="server">
<asp:listitem value="Vanilla"
selected="true">Vanilla</asp:listitem>
<asp:listitem value="Chocolate">Chocolate
</ asp:listitem>
<asp:listitem value="Strawberry">Strawberry
</ asp:listitem>
</asp:listbox>
</asp:tablecell>
</asp:tablerow>
<asp:tablerow ID="Tablerow4" runat="server">
<asp:tablecell ID="Tablecell7" runat="server">
DropDownList Control:
</asp:tablecell>
<asp:tablecell ID="Tablecell8" runat="server">
<asp:dropdownlist id="MyDropDownList" runat="server">
<asp:listitem value="Single"
selected="true">Single</asp:listitem>
<asp:listitem value="Multiline">Multiline
</ asp:listitem>
<asp:listitem value="Password">Password</asp:listitem>
</asp:dropdownlist>
</asp:tablecell>
</asp:tablerow>
<asp:tablerow ID="Tablerow5" runat="server">
<asp:tablecell ID="Tablecell9" runat="server">
CheckBoxList Control:
</asp:tablecell>
<asp:tablecell ID="Tablecell10" runat="server">
<asp:checkboxlist id="MyCheckBoxList"
repeatdirection="vertical" runat="server">
<asp:listitem value="Vanilla" text="Vanilla"/>
<asp:listitem value="Chocolate" text="Chocolate"/>
<asp:listitem value="Strawberry" text="Strawberry"/>
</asp:checkboxlist>
</asp:tablecell>
</asp:tablerow>
<asp:tablerow ID="Tablerow6" runat="server">
<asp:tablecell ID="Tablecell11" runat="server">
RadioButtonList Control:
</asp:tablecell>
<asp:tablecell ID="Tablecell12" runat="server">
<asp:radiobuttonlist id="MyRadioButtonList"
repeatdirection="Horizontal" runat="server">
<asp:listitem value="Female"
text="Female" selected="true"/>
<asp:listitem value="Male" text="Male"/>
</asp:radiobuttonlist>
</asp:tablecell>
</asp:tablerow>
</asp:table>
</form>
</body>
</html>
HAVE A HAPPY CODING!