Display Images in RadioButtonList Control in ASP.NET

Introduction

A RadioButtonList control is a collection of RadioButtons. It is used to select one item from a group of items. Usually text is displayed with RadioButtons in the RadioButtonList. But sometimes it is required to display an image in place of the text. The RadioButtonList control allows us to display an image with the RadioButtons using ListItem. In this article we will see how we can display an image with RadioButtons in a RadioButtonList control

Step 1: Create a new ASP.NET Web Application in Visual Studio. Add a folder in the root named Images. Right-click on the project name and select:

Add -> New Folder

Now add some images in this folder to show with RadioButtons in the RadioButtonList control. Right-click on the Images folder and select:

Add -> Existing Item

Step 2: Add a RadioButtonList in HTML source view of Default.aspx, as shown in the following:

<div>

    <asp:RadioButtonList ID="RadioButtonList1"

        runat="server"

        BorderStyle="Groove"

        BorderWidth="1px"

        RepeatColumns="3"

        RepeatLayout="Table">

    </asp:RadioButtonList> 

</div>

RepeatColumns of RadioButtonList is set to "3" to divide its items in three columns. For example if we have 18 items in the RadioButtonList, it will be displayed in 3 columns with 6 RadioButtons in each column.
The RepeatLayout property is used to specify the arrangement of RadioButtons inside the RadioButtonList control. By default or when it is set to "Table", RadioButtons are rendered in a table but if it is set to "Flow", it is rendered without a table.

Step 3: Write the following code in the Page Load event of Default.aspx.cs:

protected void Page_Load(object sender, EventArgs e)

{

    ListItem item;

    int i = 0;

    System.IO.FileInfo file;

 

    var Images =

        from n in System.IO.Directory.GetFiles(Server.MapPath("Images"))

        orderby n descending

        select n;

 

    foreach (var filename in Images)

    {

        file = new System.IO.FileInfo(filename);

       

        item = new ListItem("<img src='" + "Images/" + file.Name + "' alt='" + file.Name +

            "' title='"+file.Name+"'/>", i.ToString());

     

        RadioButtonList1.Items.Add(item);

        RadioButtonList1.CellPadding = 5;

        RadioButtonList1.CellSpacing = 5;

        i++;

    }

}

In the Page_Load event, first all the images in the "Images" folder is stored in an "Images" variable using a LINQ query. The Directory.GetFiles() method returns all the files in the directory with its path. A foreach loop is used to iterate through all the files. The Name property of the FileInfo class is used to extract file names from the file path.

Items in a RadioButtonList is added using its Item.Add() method. It takes ListItem as a parameter. Before that a ListItem is initialized using two string parameters. The first string is used as a label for the radio button which adds an <img> tag to display an image with the radio buttons and the second string parameter is used as the value of the radio button. A "Title" attribute is used with the <img> tag to display a ToolTip with the images on mouse hover.