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How to add RadioButtonList list item programmatically in asp.net c#

Add list item in RadioButtonList programmatically
RadioButtonList is an asp.net list web server control that allow us to render a single selection radio button group in web browser. radiobuttonlist control contains an items collection that hold all ListItem objects. we can populate a radiobuttonlist control statically by declarative syntax. we also can populate a radiobuttonlist control dynamically by data binding with a data source object.

radiobuttonlist server control's have built in properties and methods to customize it. we can change the default look and feel of radiobuttonlist control. even we can programmaticaly add or remove item from its items collection at run time.

each ListItem object have three possible properties those are Text, Value and Selected. we can create a ListItem object programmatically. we also can add this ListItem object to radiobuttonlist control's Items collection programmatically. Items collection's Items.Add(ListItem) method allow us to programmatically add a ListItem object to its collection.

Add method requrie an argument that accept a ListItem object. after adding a ListItem object to the items collection the radiobuttonlist control display this item in its radio button list.

the following asp.net c# example code demonstrate us how can we add item in radiobuttonlist server control programmatically at run time.
RadioButtonListAddItem.aspx
<%@ Page Language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">
    protected void Button1_Click(object sender, System.EventArgs e)
    {
        ListItem li = new ListItem();
        li.Text = TextBox1.Text.ToString();
        RadioButtonList1.Items.Add(li);
        Label1.Text = "ListItem added in RadioButtonList: " + li.Text;
    }
</script>

<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" runat="server">
    <title>How to add list item in RadioButtonList programmatically</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <h2 style="color:Green">RadioButtonList example: Add List Item</h2>
        <asp:Label 
             ID="Label1" 
             runat="server"
             Font-Bold="true"
             ForeColor="DodgerBlue"
             Font-Size="Large"
             >
        </asp:Label>
        <br /><br />
        <asp:Label 
             ID="Label2" 
             runat="server" 
             Text="Color List"
             Font-Bold="true"
             ForeColor="Crimson"
             >
        </asp:Label>
        <br />
        <asp:RadioButtonList 
             ID="RadioButtonList1"
             runat="server"
             BackColor="Crimson"
             ForeColor="FloralWhite"
             RepeatColumns="2"
             >
             <asp:ListItem>SpringGreen</asp:ListItem>
             <asp:ListItem>Turquoise</asp:ListItem>
             <asp:ListItem>Violet</asp:ListItem>
             <asp:ListItem>SteelBlue</asp:ListItem>
             <asp:ListItem>Snow</asp:ListItem>
        </asp:RadioButtonList>
        <br /><br />
        <asp:Label 
             ID="Label3" 
             runat="server"
             ForeColor="Crimson"
             Text="Item Text"
             >
        </asp:Label>
        <asp:TextBox 
             ID="TextBox1"
             runat="server"
             BackColor="Crimson"
             ForeColor="Snow"
             >
        </asp:TextBox>
        <br />
        <asp:Button 
             ID="Button1" 
             runat="server"
             Text="Add List Item"
             Font-Bold="true"
             ForeColor="Crimson"
             OnClick="Button1_Click"
             />
    </div>
    </form>
</body>
</html>
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