Windows表单使用DAL BLL

我的EmployeeDB类

使用系统;使用System.Collections.Generic;使用System.Linq;使用System.Text;使用System.Data.SqlClient;使用System.Data;

namespace Test {public class EmployeeDB {private string connectionString;

public EmployeeDB()
    {
        //my connectionstring info
    }

    public int CountEmployees()
    {
        SqlConnection con = new SqlConnection(connectionString);
        SqlCommand cmd = new SqlCommand("CountEmployees", con);
        cmd.CommandType = CommandType.StoredProcedure;

        try
        {
            con.Open();
            return (int)cmd.ExecuteScalar();
        }
        catch (SqlException err)
        {
            // Replace the error with something less specific.
            // You could also log the error now.
            throw new ApplicationException("Data error.");
        }
        finally
        {
            con.Close();
        }
    }

    public List<EmployeeDetails> GetEmployees()
    {
        SqlConnection con = new SqlConnection(connectionString);
        SqlCommand cmd = new SqlCommand("GetAllEmployees", con);
        cmd.CommandType = CommandType.StoredProcedure;

        // Create a collection for all the employee records.
        List<EmployeeDetails> employees = new List<EmployeeDetails>();

        try
        {
            con.Open();
            SqlDataReader reader = cmd.ExecuteReader();

            while (reader.Read())
            {
                EmployeeDetails emp = new EmployeeDetails(
                    (int)reader["EmployeeID"], (string)reader["FirstName"],
                    (string)reader["LastName"], (string)reader["TitleOfCourtesy"]);
                employees.Add(emp);
            }
            reader.Close();

            return employees;
        }
        catch (SqlException err)
        {
            // Replace the error with something less specific.
            // You could also log the error now.
            throw new ApplicationException("Data error.");
        }
        finally
        {
            con.Close();
        }
    }
}

}

我的员工详细课程

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data.SqlClient;

namespace Test
{
    public class EmployeeDetails
    {
private int employeeID;
        private string firstName;
        private string lastName;
        private string titleOfCourtesy;

        public int EmployeeID
        {
            get {return employeeID;}
            set {employeeID = value;}
        }
        public string FirstName
        {
            get {return firstName;}
            set {firstName = value;}
        }
        public string LastName
        {
            get {return lastName;}
            set {lastName = value;}
        }
        public string TitleOfCourtesy
        {
            get {return titleOfCourtesy;}
            set {titleOfCourtesy = value;}
        }

        public EmployeeDetails(int employeeID, string firstName, string lastName,
            string titleOfCourtesy)
        {
            this.employeeID = employeeID;
            this.firstName = firstName;
            this.lastName = lastName;
            this.titleOfCourtesy = titleOfCourtesy;
        }

        public EmployeeDetails(){}

    }
}

然后我构建类库并添加对我的Windows窗体项目的引用 .

这是我的主要表单的屏幕截图，该类显示但没有方法 .