Keyword not supported: 'server(local); database' - asp.net

Question

my web.config is
<connectionStrings>
<add name="taraznegarConnectionString" connectionString="Data Source=.;Initial Catalog=taraznegar;Integrated Security=True"
providerName="System.Data.SqlClient" />
</connectionStrings>
and this is my code:
namespace taraz
{
public class DAL
{
string connection = "Data Source=.;Initial Catalog=taraznegar;Integrated Security=True";
SqlConnection con;
SqlCommand cmd;
SqlDataAdapter da;
DataTable dt;
public DAL()
{
con = new SqlConnection();
con.ConnectionString = connection;
cmd = new SqlCommand();
cmd.Connection = con;
da = new SqlDataAdapter();
da.SelectCommand=cmd;
dt = new DataTable();
}
public DataTable ExecuteReader(string SQL)
{
connect();
da.SelectCommand.Connection = con;
da.SelectCommand.CommandText = SQL;
try
{
da.SelectCommand.ExecuteReader();
}
catch
{
da = null;
}
disconnect();
da.Fill(dt);
return dt;
}
public string ExcuteNonQuery(string SQL)
{
string result=null ;
cmd.CommandText = SQL;
connect();
try
{
cmd.ExecuteNonQuery();
}
catch { result = "خطا"; }
disconnect();
return result;
}
public string ExecuteScalare(string sql)
{
string result = null;
cmd.CommandText = sql;
connect();
try {
result = cmd.ExecuteScalar().ToString();
}
catch { result = "خطا"; }
disconnect();
return result;
}
void connect()
{
if (con.State == ConnectionState.Closed)
con.Open();
}
void disconnect()
{
if (con.State == ConnectionState.Open)
con.Close();
}
}
}
and when I'm using this class in my project the error is:
Server Error in '/' Application.
Keyword not supported: 'server(local); database'.
what's the probleam?

Answer 1

When you have a ConnectionString in your webconfig file then in your application you don't need to create another connection. You should use that connection. In your class DAL you are creating a new connection string. Instead of that you should use something like this-
string connectionString = ConfigurationManager.ConnectionStrings["taraznegarConnectionString"].ConnectionString;

Answer 2

For Entity Framework (database-first or model-first; when you have a physical EDMX model file) you need to use a special type of connection string which is quite different from the straight ADO.NET connection strings everyone else has mentioned so far...
The connection string must look something like:
<connectionStrings>
<add name="testEntities"
connectionString="metadata=res://*/Model1.csdl|res://*/Model1.ssdl|res://*/Model1.msl;provider=System.Data.SqlClient;provider connection string="data source=.;Initial Catalog=taraznegar;Integrated Security=True;multipleactiveresultsets=True;App=EntityFramework""
providerName="System.Data.EntityClient" />
</connectionStrings>
Inside this connection string, you'll find the provider connection string= attribute which is basically your ADO.NET connection string: