設置標簽在webmethod C＃中的可見性

Question

[System.Web.Script.Services.ScriptMethod()]
[System.Web.Services.WebMethod]
public static List<string> lfromp(string id)
{
    if (HttpContext.Current != null)
    {
        Page page = (Page)HttpContext.Current.Handler;
        Label lbltxt = (Label)page.FindControl("lbltxt");
    }
    DataTable dt = new DataTable();
    SqlConnection con = new SqlConnection("Data Source=logistics.jayom.org,1434;Initial Catalog=logistics_kl;Persist Security Info=True;User ID=kl_admin;Password=Admin@2222");
    con.Open();
    SqlCommand cmd = new SqlCommand("SPlgfpro", con); //select login from profile
    cmd.CommandType = CommandType.StoredProcedure;
    SqlParameter param;
    param = new SqlParameter("@id", id);
    param.DbType = DbType.String;
    param.Direction = ParameterDirection.Input;
    cmd.Parameters.Add(param);
    SqlDataAdapter da = new SqlDataAdapter(cmd);
    DataSet ds = new DataSet();
    da.Fill(ds);
    //dlstprofile.Items.Clear();
    //for (int i = 0; i < ds.Tables[0].Rows.Count; i++)
    //{
    //    dlstprofile.Items.Add(ds.Tables[0].Rows[i][0].ToString());
    //}
    con.Close();
    SqlCommand lfp = new SqlCommand("SPlgfpro");//select class from class
    lfp.CommandType = CommandType.StoredProcedure;
    lfp.Connection = con;
    SqlParameter dpra;
    dpra = new SqlParameter("@id", id);
    dpra.Direction = ParameterDirection.Input;
    dpra.DbType = DbType.String;
    lfp.Parameters.Add(dpra);
    con.Open();
    lfp.ExecuteNonQuery();
    SqlDataAdapter lda1 = new SqlDataAdapter(lfp);
    DataSet dds1 = new DataSet();
    lda1.Fill(dds1);
    SqlDataReader drlp = lfp.ExecuteReader();
    {
        if (drlp.Read())
        {
            id = drlp["login"].ToString();
        }

        else
        {

            //if (HttpContext.Current != null)
            //{
            //    Page page = (Page)HttpContext.Current.Handler;
            //    Label lbltxt = (Label)page.FindControl("lbltxt");
            //    lbltxt.Visible = true;
            //}
        }
        con.Close();
    }
    List<string> emp = new List<string>();
    return emp;
}

這是我的cs頁面，如果我未使用標簽，但是無法在我的標簽中使用代碼，則代碼可以正常運行

[WEBMETHOD]

這里lbltxt是我的標簽，如果我的條件不滿足，我想將其設置為可見

Answer 1

使用此樣本

function RunWebMethod() {

        $.ajax({
            type: "POST",
            url: "Test.aspx/RunWebMethod",
            contentType: "application/json; charset=utf-8",
            dataType: "json",
            async: false,
            success: function (msg) {
                 document.getElementById("LableName").style.visibility = "hidden";
            }
        });

    }

Answer 2

 static Label lbl=null;
        protected void Page_Load(object sender, EventArgs e)
        {
            lbl = (Label)this.Page.FindControl("lbltxt");
        }
        [WebMethod]
        public static List<string> lfromp(string id)
        {
            DataTable dt = new DataTable();
            SqlConnection con = new SqlConnection("MYCONNECTIONSTRING");
            con.Open();
            SqlCommand cmd = new SqlCommand("SPlgfpro", con); //select login from profile
            cmd.CommandType = CommandType.StoredProcedure;
            SqlParameter param;
            param = new SqlParameter("@id", id);
            param.DbType = DbType.String;
            param.Direction = ParameterDirection.Input;
            cmd.Parameters.Add(param);
            SqlDataAdapter da = new SqlDataAdapter(cmd);
            DataSet ds = new DataSet();
            da.Fill(ds);
            //dlstprofile.Items.Clear();
            //for (int i = 0; i < ds.Tables[0].Rows.Count; i++)
            //{
            //    dlstprofile.Items.Add(ds.Tables[0].Rows[i][0].ToString());
            //}
            con.Close();
            SqlCommand lfp = new SqlCommand("SPlgfpro");//select class from class
            lfp.CommandType = CommandType.StoredProcedure;
            lfp.Connection = con;
            SqlParameter dpra;
            dpra = new SqlParameter("@id", id);
            dpra.Direction = ParameterDirection.Input;
            dpra.DbType = DbType.String;
            lfp.Parameters.Add(dpra);
            con.Open();
            lfp.ExecuteNonQuery();
            SqlDataAdapter lda1 = new SqlDataAdapter(lfp);
            DataSet dds1 = new DataSet();
            lda1.Fill(dds1);
            SqlDataReader drlp = lfp.ExecuteReader();
            {
                if (drlp.Read())
                {
                    id = drlp["login"].ToString();
                }

                else
                {
                    Label l = lbl;
                    l.Visible = true;
                }
            }
            con.Close();
        }
    }
}

Answer 3

** now use this code:**
     Label lbl = new Label();
     lbl.Attributes.Add("ID", "id");
     lbl.Text = "";
        if (false)
        {
            lbl.Text = "your Text";
        }
        else
        {
            lbl.Text = "";
        }

Answer 4

WebMethod位於Web服務內部，您不應訪問其中的控件。 出於完全不同的目的，兩者是完全分開的東西。 無論情況如何，都應在網頁上檢查並相應地調用Web服務。 混合與網頁相關的代碼（例如訪問Web服務中的控件）確實是一種糟糕的設計。