关于C#：使用dal bll的Windows窗体


Windows form using 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；使用系统数据；

命名空间测试{公共类员工数据库{私有字符串连接字符串；

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    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EmployeeDetails类

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  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(){}

    }
}

然后我构建类库并将引用添加到我的Windows窗体项目中。

下面是我的主窗体的屏幕截图，该类显示出来，但是没有方法。enter image description here

要绑定到数据报，请执行以下操作：

  • 将BindingSource(BindingSource)添加到表单
  • 将DataGrid的DataSource属性设置为BindingSource
  • 将BindingSource的DataSource属性设置为GetEmployees()的结果。

    • 如果您的库具有以下实现，例如：

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    public interface IDataOperation
    {
        List<Employee> GetEmployees();
    }

    public class DataOperation : IDataOperation
    {
        public List<Employee> GetEmployees(){}
    }

    您的实现应该如下所示：

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    IDataOperation dataOperation = new DataOperation();

    var bindingSource = new BindingSource();
    dataGrid.DataSource = bindingSource;
    bindingSource.DataSource = dataOperation.GetEmployees();

    或者，您可以简单地将DataGrid的DataSource属性设置为getEmployees()的结果，而不使用bindingSource:

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    dataGrid.DataSource = dataOperation.GetEmployees();

    编辑：在屏幕截图中，在使用EmployeeDB之前，应先实例化它，如下面的代码所示：

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    Test.EmployeeDB employeeDB = new Test.EmployeeDB();
    dataGrid.DataSource = employeeDB.GetEmployees(); // assuming you have a dataGrid control
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