ConfigurationManager.appSettings error

Question

namespace 

using System;

using System.Collections.Generic;

using System.Configuration;

using System.Data;

using System.Data.SqlClient;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

using System.Web;

 

 

app1.config

<appSettings>

<add key="myconnection" value="Data Source=ps\sqlexpress; Initial Catalog=class; Integrated Security=True;"/>

</appSettings>

 

BllStudent.cs

public class BllStudent

{

static string connectionStr = ConfigurationManager.appSettings["myconnection"];

public DataTable getStudents()

{

SqlConnection con = new SqlConnection(connectionStr);

string sql = "select * from tbl_student";

SqlCommand cmd = new SqlCommand(sql, con);

SqlDataAdapter da = new SqlDataAdapter(cmd);

DataSet ds = new DataSet();

da.Fill(ds, "stu");

return ds.Tables["stu"];

}

public static string ConfigurationManager { get; set; }

public string System { get; set; }}

}

 

error: 'string' does not contain a definition for 'appSettings' and no extension method

'appSettings' accepting a first argument of type 'string' could be found (are you missing

a using directive or an assembly reference) 

 

Hi, this is my problem. Any if got any solution for this please help.

 

Thank you