Set MaxLength property to Multiline Textbox

In this blog, you will learn how to set MaxLength property to multiline textbox in ASP.NET using C#.

It is so easy to limit the number of characters allowed in a normal textbox by using MaxLength property, But same doesn’t work if the TextMode property of textbox is set to Multiline.

By default TextMode = "SingleLine" for a normal textbox, and it gets rendered as an input type textbox and when we set its TextMode property to MultiLine, it gets rendered as a textarea.



Note: MaxLength property works only for input type and not for textarea. So to handle this, either you can use JavaScript, jQuery or any other scripts. But in this article I used C# to handle this.

So let's take an example, and take one normal textbox and one multiline textbox and see differences before and after writing codebehind.

.aspx:

<asp:TextBox ID="txtMultiLine" runat="server" TextMode="MultiLine" MaxLength="5"></asp:TextBox>
        <br />
 <asp:TextBox ID="txtNormal" runat="server" MaxLength="5"></asp:TextBox>

CodeBehind:

using System;
using System.Web.UI;

namespace Maxlength
{
    public partial class MacLength : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            if (!Page.IsPostBack)
            {
                txtMultiLine.Attributes.Add("maxlength", txtMultiLine.MaxLength.ToString());
            }
        }
    }
}

I hope you enjoyed it. Please provide your valuable suggestions and feedback.