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Creates a selectable radio button control.

Declarative Syntax

<input type = radio id="accessID" runat="server"
   checked
   name = "radiobuttongroup"
>

For information on the individual members of this class, see HtmlInputRadioButton in the class library.

• This control does not require a closing tag.

The HtmlInputRadioButton control creates a single radio button input field. By default, each individual radio button can be selected.

You can group a set of radio buttons together in cases where only one button from the set of options needs to be selected. This is done by setting a common value for the Name attribute on each radio button in the group. For example, the following snippet creates a group of radio buttons in which only one radio button may be selected.

<input type=radio name = "optgroup1">Red
<input type=radio name = "optgroup1">White
<input type=radio name = "optgroup1">Blue

The selected state must be still be tested on the individual radio buttons, however.

HtmlInputRadioButton enables programming of the HTML <input type=radio> element. The sample below illustrates use of the HtmlInputRadioButton control.

• Responding to User Selection in Radio Button Controls

This example shows a simple way to dynamically gather and display the value selected from a group of HtmlRadioButton controls. In this case, the value is simply rendered via a <span> generic control.

Responding to User Selection in Radio Button Controls Run Sample | View Source

Note that the HtmlRadioButton control does not have an event that notifies the server when a user has selected a radio button option. You must rely on using one of the button controls — such as the HtmlInputButton, HtmlInputImage, or HtmlButton — to cause a postback that will allow to program the HtmlRadioButton control itself.

To respond to User Selection in Radio button controls:

1. Declare a set of radio button controls, a button control that will cause postback when clicked by the user, and a <span> control to render the postback message.

   <form runat="server">
   
      <input type=radio id="Radio1" name = "flavor" 
         value="Strawberry" runat="server" />
   Strawberry<br>
      <input type=radio id="Radio2" name = "flavor" 
         value="Vanilla" runat="server" />
   Vanilla<br>
      <input type=radio id="Radio3" name = "flavor" 
         value="Chocolate" runat="server" />
   Chocolate
   
      <p><input type=button id="Button1" value="Enter" 
         onServerClick = "Button1_Click" runat="server">
   
      <p><span id="Message" runat="server" />
   
   </form>

2. Create event handling code to process the information gathered from the radio button group.

   <script language="C#" runat="server">
   void Button1_Click ( object Source, EventArgs e ) {
      Message.InnerHtml = "Looks like you prefer ";
      if ( Radio1.Checked ) Message.InnerHtml += Radio1.Value;
      else if ( Radio2.Checked ) Message.InnerHtml += Radio2.Value;
      else if ( Radio3.Checked ) Message.InnerHtml += Radio3.Value;
      else Message.InnerHtml = "";
   }
   </script>

HtmlInputRadioButton Class   Web Forms Events and Handlers