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!