几个可用的类的分享

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

using System.Configuration;
namespace MySchool.DAL
{
  public static  class SQLHelper
    {
      //用静态的方法调用的时候不用创建SQLHelper的实例
      //Execetenonquery
     // public static string Constr = "server=HAPPYPIG\\SQLMODEL;database=shooltest;uid=sa;";
      public static string Constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
      public static int id;
      /// <summary>
      /// 执行NonQuery命令
      /// </summary>
      /// <param name="cmdTxt"></param>
      /// <param name="parames"></param>
      /// <returns></returns>
      public static int ExecuteNonQuery(string cmdTxt, params SqlParameter[] parames)
      {
          return ExecuteNonQuery(cmdTxt, CommandType.Text, parames);
      }
      //可以使用存储过程的ExecuteNonquery
      public static int ExecuteNonQuery(string cmdTxt, CommandType cmdtype, params SqlParameter[] parames)
      {
          //判断脚本是否为空 ，直接返回0
          if (string.IsNullOrEmpty(cmdTxt))
          {
              return 0;
          }
          using (SqlConnection con = new SqlConnection(Constr))
          {
              using (SqlCommand cmd = new SqlCommand(cmdTxt, con))
              {
                  if (parames != null)
                  {
                      cmd.CommandType = cmdtype;
                      cmd.Parameters.AddRange(parames);
                  }
                  con.Open();
                  return cmd.ExecuteNonQuery();
              }
          }
      }
      public static SqlDataReader ExecuteDataReader(string cmdTxt, params SqlParameter[] parames)
      {
          return ExecuteDataReader(cmdTxt, CommandType.Text, parames);
      }
      //SQLDataReader存储过程方法
      public static SqlDataReader ExecuteDataReader(string cmdTxt, CommandType cmdtype, params SqlParameter[] parames)
      {
          if (string.IsNullOrEmpty(cmdTxt))
          {
              return null;
          }
          SqlConnection con = new SqlConnection(Constr);

          using (SqlCommand cmd = new SqlCommand(cmdTxt, con))
          {
              cmd.CommandType = cmdtype;
              if (parames != null)
              {
                  
                  cmd.Parameters.AddRange(parames);
              }
              con.Open();
              //把reader的行为加进来。当reader释放资源的时候，con也被一块关闭
              return cmd.ExecuteReader(System.Data.CommandBehavior.CloseConnection);
          }

      }
      public static DataTable ExecuteDataTable(string sql, params SqlParameter[] parames)
      {
          return ExecuteDataTable(sql, CommandType.Text, parames);
      }
      //调用存储过程的类，关于(ExecuteDataTable)
      public static DataTable ExecuteDataTable(string sql, CommandType cmdType, params SqlParameter[] parames)
      {
          if (string.IsNullOrEmpty(sql))
          {
              return null;
          }
          DataTable dt = new DataTable();
          using (SqlDataAdapter da = new SqlDataAdapter(sql, Constr))
          {
              da.SelectCommand.CommandType = cmdType;
              if (parames != null)
              {
                  da.SelectCommand.Parameters.AddRange(parames);
              }
              da.Fill(dt);
              return dt;
          }
      }
    
      /// <summary>
      /// ExecuteScalar
      /// </summary>
      /// <param name="cmdTxt">第一个参数，SQLServer语句</param>
      /// <param name="parames">第二个参数，传递0个或者多个参数</param>
      /// <returns></returns>
      public static object ExecuteScalar(string cmdTxt, params SqlParameter[] parames)
      {
          return ExecuteScalar(cmdTxt, CommandType.Text, parames);
      }  
      //可使用存储过程的ExecuteScalar
      public static object ExecuteScalar(string cmdTxt, CommandType cmdtype, params SqlParameter[] parames)
      {
          if (string.IsNullOrEmpty(cmdTxt))
          {
              return null;
          }
          using (SqlConnection con = new SqlConnection(Constr))
          {
              using (SqlCommand cmd = new SqlCommand(cmdTxt, con))
              {
                  cmd.CommandType = cmdtype;
                  if (parames != null)
                  {
                      cmd.Parameters.AddRange(parames);
                  }
                  con.Open();
                return   cmd.ExecuteScalar();
              }
          }
          
      }
      //调用存储过程的DBHelper类（关于ExeceutScalar,包含事务,只能处理Int类型，返回错误号）
      public static object ExecuteScalar(string cmdTxt, CommandType cmdtype,SqlTransaction sqltran, params SqlParameter[] parames)
      {
           if (string.IsNullOrEmpty(cmdTxt))
          {
              return 0;
          }
          using (SqlConnection con = new SqlConnection(Constr))
          {
              int sum = 0;
              using (SqlCommand cmd = new SqlCommand(cmdTxt, con))
              {
                  cmd.CommandType=cmdtype;
                  if (parames != null)
                  {
                      cmd.Parameters.AddRange(parames);
                  }
                  con.Open();
                  sqltran = con.BeginTransaction();
                  try
                  {
                      cmd.Transaction = sqltran;
                      sum=Convert.ToInt32( cmd.ExecuteScalar());
                      sqltran.Commit();
                  }
                  catch (SqlException ex)
                  {
                      sqltran.Rollback();
                  }
                  return sum;
              }
          }
      }
    }
}

       //以返回表的方式加载下拉框
          public DataTable LoadCombox()
          {
              string sql = "select * from Grade";
              DataTable dt = SQLHelper.ExecuteDataTable(sql);
              return dt;
          }

using System;
using System.Collections.Generic;
using System.Data;
using System.Data.SqlClient;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;

namespace MySchool.DAL
{
   public class MyTool
    {
        /// <summary>
        /// DataSetToList
        /// </summary>
        /// <typeparam name="T">转换类型</typeparam>
        /// <param name="dataSet">数据源</param>
        /// <param name="tableIndex">需要转换表的索引</param>
        /// <returns></returns>
        public List<T> DataTableToList<T>(DataTable dt)
        {
            //确认参数有效
            if (dt == null )
                return null;
            List<T> list = new List<T>();

            for (int i = 0; i < dt.Rows.Count; i++)
            {
                //创建泛型对象
                T _t = Activator.CreateInstance<T>();
                //获取对象所有属性
                PropertyInfo[] propertyInfo = _t.GetType().GetProperties();
                for (int j = 0; j < dt.Columns.Count; j++)
                {
                    foreach (PropertyInfo info in propertyInfo)
                    {
                        //属性名称和列名相同时赋值
                        if (dt.Columns[j].ColumnName.ToUpper().Equals(info.Name.ToUpper()))
                        {
                            if (dt.Rows[i][j] != DBNull.Value)
                            {
                                info.SetValue(_t, dt.Rows[i][j], null);
                            }
                            else
                            {
                                info.SetValue(_t, null, null);
                            }
                            break;
                        }
                    }
                }
                list.Add(_t);
            }
            return list;
        }
    }
}

         public List<Grade> Loadcombox2() 
          {
              string sql = "select * from Grade";
              DataTable dt = SQLHelper.ExecuteDataTable(sql);
              //方法一：
              foreach (DataRow row in dt.Rows)
              {
                  //每一个row代表表中的一行,所以一行对应一个年级对象
                  Grade grade = new Grade();
                  grade.GradeId = Convert.ToInt32(row["gradeid"]);
                  grade.GradeName = row["gradename"].ToString();
                  list.Add(grade);
              }

              //方法二：(使用MyTool类)
              MyTool tool=new MyTool();
              list = tool.DataTableToList<Grade>(dt);
              return list;
          }

using System;
using System.Collections.Generic;
using System.Text;
using System.Windows.Forms;

/// <summary>
/// 消息条回调函数委托
/// </summary>
public delegate void DGMsgDiv();
    /// <summary>
    /// 消息条类 带Timer计时
    /// </summary>
public class MsgDiv : System.Windows.Forms.Label
{
    private Timer timerLable = new Timer();
    /// <summary>
    /// 消息回调 委托对象
    /// </summary>
    private DGMsgDiv dgCallBack = null;

    #region 计时器
    /// <summary>
    /// 计时器
    /// </summary>
    public Timer TimerMsg
    {
        get { return timerLable; }
        set { timerLable = value; }
    } 
    #endregion

    #region  MsgDiv构造函数
    /// <summary>
    /// MsgDiv构造函数
    /// </summary>
    public MsgDiv()
    {
        InitallMsgDiv(7, 7);
    }

    /// <summary>
    /// MsgDiv构造函数
    /// </summary>
    /// <param name="x">定位x轴坐标</param>
    /// <param name="y">定位y轴坐标</param>
    public MsgDiv(int x, int y)
    {
        InitallMsgDiv(x, y);
    }
    #endregion

    #region  初始化消息条
    /// <summary>
    /// 初始化消息条
    /// </summary>
    private void InitallMsgDiv(int x, int y)
    {
        this.AutoSize = true;
        this.BackColor = System.Drawing.Color.FromArgb(((int)(((byte)(255)))), ((int)(((byte)(255)))), ((int)(((byte)(192)))));
        this.BorderStyle = System.Windows.Forms.BorderStyle.FixedSingle;
        //this.ContextMenuStrip = this.cmsList;
        this.Font = new System.Drawing.Font("宋体", 11F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((byte)(134)));
        this.ForeColor = System.Drawing.Color.Red;
        this.Location = new System.Drawing.Point(x, y);
        this.MaximumSize = new System.Drawing.Size(980, 525);
        this.Name = "msgDIV";
        this.Padding = new System.Windows.Forms.Padding(7);
        this.Size = new System.Drawing.Size(71, 31);
        this.TabIndex = 1;
        this.Text = "消息条";
        this.Visible = false;
        //给委托添加事件
        this.DoubleClick += new System.EventHandler(this.msgDIV_DoubleClick);
        this.MouseLeave += new System.EventHandler(this.msgDIV_MouseLeave);
        this.MouseHover += new System.EventHandler(this.msgDIV_MouseHover);
        this.timerLable.Interval = 1000;
        this.timerLable.Tick += new System.EventHandler(this.timerLable_Tick);
    }
    #endregion

    #region 将消息条添加到指定容器上
    /// <summary>
    /// 将消息条添加到指定容器上Form
    /// </summary>
    /// <param name="form"></param>
    public void AddToControl(Form form)
    {
        form.Controls.Add(this);
    }
    /// <summary>
    /// 将消息条添加到指定容器上GroupBox
    /// </summary>
    /// <param name="form"></param>
    public void AddToControl(GroupBox groupBox)
    {
        groupBox.Controls.Add(this);
    }
    /// <summary>
    /// 将消息条添加到指定容器上Panel
    /// </summary>
    /// <param name="form"></param>
    public void AddToControl(Panel panel)
    {
        panel.Controls.Add(this);
    }
    #endregion

    //---------------------------------------------------------------------------
    #region 消息显示 的相关参数们 hiddenClick，countNumber，constCountNumber
    /// <summary>
    /// 当前显示了多久的秒钟数
    /// </summary>
    int hiddenClick = 0;
    /// <summary>
    /// 要显示多久的秒钟数 可变参数
    /// </summary>
    int countNumber = 3;
    /// <summary>
    /// 要显示多久的秒钟数 固定参数
    /// </summary>
    int constCountNumber = 3; 
    #endregion

    #region 计时器 显示countNumber秒钟后自动隐藏div -timerLable_Tick(object sender, EventArgs e)
    private void timerLable_Tick(object sender, EventArgs e)
    {
        if (hiddenClick > countNumber - 2)
        {
            MsgDivHidden();
        }
        else
        {
            hiddenClick++;
            //RemainCount();
        }
    } 
    #endregion

    #region 隐藏消息框 并停止计时 +void MsgDivHidden()
    /// <summary>
    /// 隐藏消息框 并停止计时
    /// </summary>
    public void MsgDivHidden()
    {
        this.Text = "";
        this.Visible = false;
        this.hiddenClick = 0;
        //this.tslblRemainSecond.Text = "";
        if (this.timerLable.Enabled == true)
            this.timerLable.Stop();

        //调用 委托 然后清空委托
        if (dgCallBack != null && dgCallBack.GetInvocationList().Length > 0)
        {
            dgCallBack();
            dgCallBack -= dgCallBack;
        }
    } 
    #endregion

    #region 在消息框中显示消息字符串 +void MsgDivShow(string msg)
    /// <summary>
    /// 在消息框中显示消息字符串
    /// </summary>
    /// <param name="msg">要显示的字符串</param>
    public void MsgDivShow(string msg)
    {
        this.Text = msg;
        this.Visible = true;
        this.countNumber = constCountNumber;//默认设置显示秒数为10;
        this.hiddenClick = 0;//重置倒数描述
        this.timerLable.Start();
    } 
    #endregion

    #region 在消息框中显示消息字符串 并在消息消失时 调用回调函数 +void MsgDivShow(string msg, DGMsgDiv callback)
    /// <summary>
    /// 在消息框中显示消息字符串 并在消息消失时 调用回调函数
    /// </summary>
    /// <param name="msg">要显示的字符串</param>
    /// <param name="callback">回调函数</param>
    public void MsgDivShow(string msg, DGMsgDiv callback)
    {
        MsgDivShow(msg);
        dgCallBack = callback;
    }
    #endregion

    #region 在消息框中显示消息字符串 并在指定时间消息消失时 调用回调函数 +void MsgDivShow(string msg, int seconds, DGMsgDiv callback)
    /// <summary>
    /// 在消息框中显示消息字符串 并在消息消失时 调用回调函数
    /// </summary>
    /// <param name="msg">要显示的字符串</param>
    /// <param name="seconds">消息显示时间</param>
    /// <param name="callback">回调函数</param>
    public void MsgDivShow(string msg, int seconds, DGMsgDiv callback)
    {
        MsgDivShow(msg, seconds);
        dgCallBack = callback;
    }  
    #endregion

    #region 在消息框中显示消息字符串，并指定消息框显示秒数 +void MsgDivShow(string msg, int seconds)
    /// <summary>
    /// 在消息框中显示消息字符串，并指定消息框显示秒数
    /// </summary>
    /// <param name="msg">要显示的字符串</param>
    /// <param name="seconds">消息框显示秒数</param>
    public void MsgDivShow(string msg, int seconds)
    {
        this.Text = msg;
        this.Visible = true;
        this.countNumber = seconds;
        this.hiddenClick = 0;//重置倒数描述
        this.timerLable.Start();
    } 
    #endregion

    //---------------------------------------------------------------------------
    #region 事件们～～～！ msgDIV_MouseHover，msgDIV_MouseLeave，msgDIV_DoubleClick
    //当鼠标停留在div上时 停止计时
    private void msgDIV_MouseHover(object sender, EventArgs e)
    {
        if (this.timerLable.Enabled == true)
            this.timerLable.Stop();
    }
    //当鼠标从div上移开时 继续及时
    private void msgDIV_MouseLeave(object sender, EventArgs e)
    {
        //当消息框正在显示、回复框没显示、计时器正停止的时候，重新启动计时器
        if (this.Visible == true && this.timerLable.Enabled == false)
            this.timerLable.Start();
    }
    //双击消息框时关闭消息框
    private void msgDIV_DoubleClick(object sender, EventArgs e)
    {
        MsgDivHidden();
    } 
    #endregion

}

 private void Form1_Load(object sender, EventArgs e)
        {
            //首先显示“呵呵”，3秒后 调用Test方法消息框显示“哈哈”
            msgDiv1.MsgDivShow("呵呵",3,Test);
        }

        public void Test()
        {
            MessageBox.Show("哈哈");
        }