Customization in ASP.NET Web Forms DropDownList

24 May 20246 minutes to read

Adding watermark text

It provides the short description of the expected value in dropdown and will display the text until any item is selected. You can set this text using WatermarkText property.

HTML

<ej:DropDownList ID="DropDownList1" runat="server" WatermarkText="Select an Item">
            <Items>
                <ej:DropDownListItem Text="ListItem 1" Value="item1"></ej:DropDownListItem>
                <ej:DropDownListItem Text="ListItem 2" Value="item2"></ej:DropDownListItem>
                <ej:DropDownListItem Text="ListItem 3" Value="item3"></ej:DropDownListItem>
                <ej:DropDownListItem Text="ListItem 4" Value="item4"></ej:DropDownListItem>
                <ej:DropDownListItem Text="ListItem 5" Value="item5"></ej:DropDownListItem>
            </Items>
        </ej:DropDownList>

Applying Rounded Corner

You can use ShowRoundedCorner property to add rounded borders to the input and popup elements. By default, rounded corner property is disabled in DropDownList.

HTML

<ej:DropDownList ID="DropDownList1" runat="server" ShowRoundedCorner="true">
            <Items>
                <ej:DropDownListItem Text="ListItem 1" Value="item1"></ej:DropDownListItem>
                <ej:DropDownListItem Text="ListItem 2" Value="item2"></ej:DropDownListItem>
                <ej:DropDownListItem Text="ListItem 3" Value="item3"></ej:DropDownListItem>
                <ej:DropDownListItem Text="ListItem 4" Value="item4"></ej:DropDownListItem>
                <ej:DropDownListItem Text="ListItem 5" Value="item5"></ej:DropDownListItem>
            </Items>
        </ej:DropDownList>

IMPORTANT

The browser support details for rounded corner is given here.

Enable/Disable the control

The Enabled property is used to indicate whether the control can respond to the user interaction or not. You can disable it by assigning false to this property. When the control is disabled state, you cannot interact with the control.

HTML

<ej:DropDownList ID="DropDownList1" runat="server" Enabled="false">
        <Items>
            <ej:DropDownListItem Text="ListItem 1" Value="item1"></ej:DropDownListItem>
            <ej:DropDownListItem Text="ListItem 2" Value="item2"></ej:DropDownListItem>
            <ej:DropDownListItem Text="ListItem 3" Value="item3"></ej:DropDownListItem>
            <ej:DropDownListItem Text="ListItem 4" Value="item4"></ej:DropDownListItem>
            <ej:DropDownListItem Text="ListItem 5" Value="item5"></ej:DropDownListItem>
        </Items>
    </ej:DropDownList>

Applying HTML Attributes

Additional HTML attributes can be applied to the control by using HtmlAttributes property. The attributes such as name, required, read-only and disabled are directly applied to the input element of DropDownList, and other attributes such as style, class will be applied to the outer wrapper element of DropDownList.

HTML

<ej:DropDownList ID="DropDownList1" runat="server" DataHtmlAttributesField="HtmlAttr" DataTextField="Text" DataValueField="Value"></ej:DropDownList>

C#

protected void Page_Load(object sender, EventArgs e)
        {
            List<Data> DropDownData = new List<Data>();
            DropDownData.Add(new Data { Value = "item1", Text = "ListItem 1", HtmlAttr="style='border:1px solid red;'" });
            DropDownData.Add(new Data { Value = "item2", Text = "ListItem 2", HtmlAttr = "style='border:1px solid red;'" });
            DropDownData.Add(new Data { Value = "item3", Text = "ListItem 3", HtmlAttr = "style='border:1px solid red;'" });
            DropDownData.Add(new Data { Value = "item4", Text = "ListItem 4", HtmlAttr = "style='border:1px solid red;'" });
            DropDownData.Add(new Data { Value = "item5", Text = "ListItem 5", HtmlAttr = "style='border:1px solid red;'" });
            DropDownList1.DataSource = DropDownData;
        }
        public class Data
        {
            public string Value { get; set; }
            public string Text { get; set; }
            public string HtmlAttr { get; set; }
        }