BOUTON QUI EMPECHE LE MULTI CLIC AVANT LA FIN DU TRAITEMENT. DISABLE DOUBLE POSTBACK

namespace WebControlLibrary1
{
    using System;
    using System.ComponentModel;
    using System.Text;
    using System.Web.UI;
    using System.Web.UI.WebControls;

    /// <summary>
    /// Button who disable double post back
    /// </summary>
    [DefaultProperty("Text")]
    [ToolboxData("<{0}:CustomButton runat=server></{0}:CustomButton>")]
    public class CustomButton : Button 
    {
        private bool _useValidation = false;
        private string _waitingText = "Patientez svp...";

        /// <summary>
        /// Gets or sets a value indicating whether [use validation].
        /// </summary>
        /// <value><c>true</c> if [use validation]; otherwise, <c>false</c>.</value>
        [Category("Appearance")]
        [Browsable(true)]
        public bool UseValidation 
        {
            get { return _useValidation; } 
            set {_useValidation = value;} 
        }

        [Category("Appearance")]
        [Browsable(true)]
        public string WaitingText
        {
            get { return _waitingText; }
            set { _waitingText = value; }
        }

        /// <summary>
        /// Raises the <see cref="E:System.Web.UI.Control.Load"/> event.
        /// </summary>
        /// <param name="e">The <see cref="T:System.EventArgs"/> object that contains the event data.</param>
        protected override void OnLoad(EventArgs e)
        {
            StringBuilder sbValid = new StringBuilder();
            if (_useValidation)
            {
                sbValid.Append("if (typeof(Page_ClientValidate) == 'function') { ");
                sbValid.Append("if (Page_ClientValidate() == false) { return false; }} ");
            }

            sbValid.Append(string.Format("this.value = '{0}';", _waitingText));
            sbValid.Append("this.disabled = true;");
            sbValid.Append(Page.ClientScript.GetPostBackEventReference(this, null).ToString());
            sbValid.Append(";");

            Attributes.Add("onclick", sbValid.ToString());
            base.OnLoad(e);
        }
    }
}