Enable Disable HTML TextBox using C# in ASP.Net

Hi priyajsr,

I have created sample that full-fill your requirement. Please refer the below sample code. You need to remove the attribute disable instead of assigning false value to textbox.

HTML

<input id="txtDiscount" type="text" name="txtDiscount" runat="server" />
<asp:Button ID="btnEnable" Text="Enable" runat="server" OnClick="Enable" />
<asp:Button ID="btnDisable" Text="Disable" runat="server" OnClick="Disable" />

C#

protected void Enable(object sender, EventArgs e)
{
    txtDiscount.Attributes.Remove("disabled");
}

protected void Disable(object sender, EventArgs e)
{
    txtDiscount.Attributes.Add("disabled", "disabled");
}