protected void btnCheckUserName_OnClick(object sender, EventArgs e) { if (txtUsername.zIsNullOrEmpty()) { lblErrorUserName.Text = "Please Enter Username."; txtUsername.Attributes.Add("style", "border-color:transparent transparent #ff0b0b"); txtUsername.Focus(); return; } int?UsersId = null; if (LoginUtilities.IsValidUserName(ref UsersId, txtUsername.Text)) { Session["CheckUsersId"] = UsersId.ToString(); SetControl(true); } else { lblErrorUserName.Text = "Sorry, We doesn't recognize " + txtUsername.Text + "."; txtUsername.Attributes.Add("style", "border-color:transparent transparent #ff0b0b"); txtUsername.Focus(); } }