Update command in SQL Stored procedure

update std_table set Std_no= @Std_no, Std_name=@Std_name, Std_class=@Std_class, Std_city=@Std_city, Std_phone=@Std_phone, Std_age=@Std_age where Std_name=@Std_name

select * from std_table  where Std_name='gopadfa'

CREATE TABLE STD_TABLE
(
Std_no varchar(10),
Std_name varchar(10),
Std_class varchar(10),
Std_city varchar(10),
Std_phone varchar(10), 
Std_age int
)

insert into STD_TABLE VALUES('1001','AA1','BB1','CC1','123456',22)
insert into STD_TABLE VALUES('1002','AA2','BB2','CC2','123457',23)

CREATE PROC STD_DATA_UPDATA
@Std_no varchar(10), @Std_name varchar(10), @Std_class varchar(10), @Std_city varchar(10),@Std_phone varchar(10), @Std_age int
as
update std_table set Std_name=@Std_name, Std_class=@Std_class, Std_city=@Std_city, Std_phone=@Std_phone, Std_age=@Std_age where Std_no=@Std_no

EXEC STD_DATA_UPDATA @STD_NO='1001', @STD_NAME='GOPADFA',@STD_CLASS='ASP.NET',@STD_CITY = 'AGA', @STD_PHONE = '98745', @STD_AGE = 30 

protected btnUpdate_Click(object sender, EventArgs e)
{
         try
        {
            con.Open();
            cmd = new SqlCommand("Update_Employee_Details", con);
            cmd.CommandType = CommandType.StoredProcedure;
            cmd.Parameters.AddWithValue("@EMPNO", value1);
            cmd.Parameters.AddWithValue("@Ename", value2);
            cmd.Parameters.AddWithValue("@Job", Job.Text);
            
            cmd.ExecuteNonQuery();

        }
        catch (Exception ex)
        {
        }
        finally
        {
            con.Close();
            con.Dispose();
        }
}