C#中的DBHelp类怎么写？

[MXY169]

如题

[子夜__]

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

namespace M_Common.SqlHelper
{

    /******************************

    ******************************/
    public class SqlHelper
    {
        private static SqlConnection cn = null;
        private static SqlCommand cmd = null;

        public SqlHelper()
        {

        }

        /// <summary>
        /// 判断连接状态
        /// </summary>
        /// <returns>返回连接状态</returns>
        private static SqlConnection GetConn()
        {
            string ConnStr = M_Common.Helper.ConfigHelper.GetconnMsSql.ToString();
            cn = new SqlConnection(ConnStr);
            if (cn.State != ConnectionState.Open)
            {
                cn.Open();
            }
            return cn;
        }


        /// <summary>
        /// 获取某表的某个字段的最大值
        /// </summary>
        /// <param name="FieldName">字段名</param>
        /// <param name="TableName">表明</param>
        /// <returns>返回最大值</returns>
        public static int GetMaxID(string FieldName, string TableName)
        {
            string strsql = "select max(" + FieldName + ")+1 from " + TableName;
            object obj = SqlHelper.GetSingle(strsql);
            if (obj == null)
            {
                return 1;
            }
            else
            {
                return int.Parse(obj.ToString());
            }
        }
        /// <summary>
        /// 执行一条计算查询结果语句，返回查询结果（object）。
        /// </summary>
        /// <param name="SQLString">计算查询结果语句</param>
        /// <returns>查询结果（object）</returns>
        public static object GetSingle(string SQLString)
        {
            using (SqlCommand cmd = new SqlCommand(SQLString, GetConn()))
            {
                try
                {
                    object obj = cmd.ExecuteScalar();
                    if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
                    {
                        return null;
                    }
                    else
                    {
                        return obj;
                    }
                }
                catch (System.Data.SqlClient.SqlException e)
                {
                    throw e;
                }
            }

        }

        /// <summary>
        /// 带参数返回一行一列ExecuteScalar
        /// </summary>
        /// <param name="cmdtext">存储过程或者SQL语句</param>
        /// <param name="para">参数数组</param>
        /// <param name="ct">命令类型</param>
        /// <returns>返回一行一列value</returns>
        public static int ExecuteScalar(string cmdtext, SqlParameter[] para, CommandType ct)
        {
            int value;
            try
            {
                cmd = new SqlCommand(cmdtext, GetConn());
                cmd.CommandType = ct;
                cmd.Parameters.AddRange(para);
                value = Convert.ToInt32(cmd.ExecuteScalar());
            }
            catch (Exception ex)
            {
                throw ex;
            }
            finally
            {
                if (cn.State == ConnectionState.Open)
                {
                    cn.Close();
                }
            }
            return value;
        }
        /// <summary>
        /// 执行无参的操作
        /// </summary>
        /// <param name="cmdtext">SQL语句或存储过程</param>
        /// <param name="ct">CMD的类型</param>
        /// <returns>处理后的值</returns>
        public static int ExecuteNonQuery(string cmdtext, CommandType ct)
        {
            int value;
            try
            {
                cmd = new SqlCommand(cmdtext, GetConn());
                cmd.CommandType = ct;
                value = cmd.ExecuteNonQuery() > 0 ? 1 : 0;
            }
            catch (Exception ex)
            {
                throw ex;
            }
            finally
            {
                if (cn.State == ConnectionState.Open)
                {
                    cn.Close();
                }
            }
            return value;
        }

        /// <summary>
        /// 执行带参的增.删.改操作
        /// </summary>
        /// <param name="cmdtext">SQL语句或存储过程</param>
        /// <param name="para">参数数组</param>
        /// <param name="ct">CMD类型</param>
        /// <returns>处理后的值</returns>
        public static int ExecuteNonQuery(string cmdtext, SqlParameter[] para, CommandType ct)
        {
            int value;
            using (cmd = new SqlCommand(cmdtext, GetConn()))
            {
                cmd.CommandType = ct;
                cmd.Parameters.AddRange(para);
                value = cmd.ExecuteNonQuery() > 0 ? 1 : 0;
            }
            return value;
        }

        /// <summary>
        /// 执行无参的查询 返回DataTable
        /// </summary>
        /// <param name="cmdtext">存储过程名称或SQL语句</param>
        /// <param name="ct">命令类型</param>
        /// <returns>返回DataTable</returns>
        public static DataTable ReturnDataTable(string cmdtext, CommandType ct)
        {
            DataTable dt = new DataTable();
            cmd = new SqlCommand(cmdtext, GetConn());
            //类型
            cmd.CommandType = ct;
            SqlDataReader dr = null;
            //连接池 读完自动释放Connection
            using (dr = cmd.ExecuteReader(CommandBehavior.CloseConnection))
            {
                //用委托填充DataTable
                dt.Load(dr);
            }
            return dt;
        }

        /// <summary>
        /// 执行有参的查询 返回DataTable
        /// </summary>
        /// <param name="cmdtext">存储过程名称或SQL语句</param>
        /// <param name="ct">命令类型</param>
        /// <param name="para">参数数组</param>
        /// <returns>返回DataTable</returns>
        public static DataTable ReturnDataTable(string cmdtext, CommandType ct, SqlParameter[] para)
        {
            DataTable dt = new DataTable();
            cmd = new SqlCommand(cmdtext, GetConn());
            //类型
            cmd.CommandType = ct;
            //参数数组
            cmd.Parameters.AddRange(para);
            SqlDataReader dr = null;
            //连接池 读完自动释放Connection
            using (dr = cmd.ExecuteReader(CommandBehavior.CloseConnection))
            {
                //用委托填充DataTable
                dt.Load(dr);
            }
            return dt;
        }

        /// <summary>
        /// 执行无参的查询 返回DataSet
        /// </summary>
        /// <param name="cmdtext">存储过程名称或SQL语句</param>
        /// <param name="ct">命令类型</param>
        /// <returns>返回DataSet</returns>
        public static DataSet ReturnDataSet(string cmdtext, CommandType ct)
        {
            cmd = new SqlCommand(cmdtext, GetConn());
            //类型
            cmd.CommandType = ct;
            SqlDataAdapter da = new SqlDataAdapter(cmd);
            DataSet ds = new DataSet();
            try
            {
                da.Fill(ds);
            }
            catch (Exception err)
            {

                throw err;
            }
            finally
            {
                if (cn.State != ConnectionState.Closed)
                {
                    cn.Close();
                }
            }
            return ds;
        }




        /// <summary>
        /// 执行有参的查询 返回DataSet
        /// </summary>
        /// <param name="cmdtext">存储过程名称或SQL语句</param>
        /// <param name="ct">命令类型</param>
        /// <param name="para">参数数组</param>
        /// <returns>返回DataSet</returns>
        public static DataSet ReturnDataSet(string cmdtext, CommandType ct, SqlParameter[] para)
        {
            cmd = new SqlCommand(cmdtext, GetConn());
            //类型
            cmd.CommandType = ct;
            //参数数组
            cmd.Parameters.AddRange(para);
            SqlDataAdapter da = new SqlDataAdapter(cmd);
            DataSet ds = new DataSet();
            try
            {
                da.Fill(ds);
            }
            catch (Exception err)
            {

                throw err;
            }
            finally
            {
                if (cn.State != ConnectionState.Closed)
                {
                    cn.Close();
                }
            }
            return ds;
        }

    }
}

建立一个类 命名SqlHelper.cs

拷贝进去就行了

[子夜__]

        #region  执行简单SQL语句

        /// <summary>
        /// 执行SQL语句，返回影响的记录数
        /// </summary>
        /// <param name="SQLString">SQL语句</param>
        /// <returns>影响的记录数</returns>
        public static int ExecuteSql(string SQLString)
        {
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                using (SqlCommand cmd = new SqlCommand(SQLString, connection))
                {
                    try
                    {
                        connection.Open();
                        int rows = cmd.ExecuteNonQuery();                     
                        return rows;
                    }
                    catch (System.Data.SqlClient.SqlException E)
                    {
                        connection.Close();
                        throw new Exception(E.Message);
                    }
                }
            }
        }

        /// <summary>
        /// 执行多条SQL语句，实现数据库事务。
        /// </summary>
        /// <param name="SQLStringList">多条SQL语句</param>		
        public static void ExecuteSqlTran(ArrayList SQLStringList)
        {
            using (SqlConnection conn = new SqlConnection(connectionString))
            {
                conn.Open();
                SqlCommand cmd = new SqlCommand();
                cmd.Connection = conn;
                SqlTransaction tx = conn.BeginTransaction();
                cmd.Transaction = tx;
                try
                {
                    for (int n = 0; n < SQLStringList.Count; n++)
                    {
                        string strsql = SQLStringList[n].ToString();
                        if (strsql.Trim().Length > 1)
                        {
                            cmd.CommandText = strsql;
                            cmd.ExecuteNonQuery();
                        }
                    }
                    tx.Commit();
                }
                catch (System.Data.SqlClient.SqlException E)
                {
                    tx.Rollback();
                    throw new Exception(E.Message);
                }
            }
        }
        /// <summary>
        /// 执行带一个存储过程参数的的SQL语句。
        /// </summary>
        /// <param name="SQLString">SQL语句</param>
        /// <param name="content">参数内容,比如一个字段是格式复杂的文章，有特殊符号，可以通过这个方式添加</param>
        /// <returns>影响的记录数</returns>
        public static int ExecuteSql(string SQLString, string content)
        {
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                SqlCommand cmd = new SqlCommand(SQLString, connection);
                System.Data.SqlClient.SqlParameter myParameter = new System.Data.SqlClient.SqlParameter("@content", SqlDbType.NText);
                myParameter.Value = content;
                cmd.Parameters.Add(myParameter);
                try
                {
                    connection.Open();
                    int rows = cmd.ExecuteNonQuery();
                    return rows;
                }
                catch (System.Data.SqlClient.SqlException E)
                {
                    throw new Exception(E.Message);
                }
                finally
                {
                    cmd.Dispose();
                    connection.Close();
                }
            }
        }
        /// <summary>
        /// 向数据库里插入图像格式的字段(和上面情况类似的另一种实例)
        /// </summary>
        /// <param name="strSQL">SQL语句</param>
        /// <param name="fs">图像字节,数据库的字段类型为image的情况</param>
        /// <returns>影响的记录数</returns>
        public static int ExecuteSqlInsertImg(string strSQL, byte[] fs)
        {
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                SqlCommand cmd = new SqlCommand(strSQL, connection);
                System.Data.SqlClient.SqlParameter myParameter = new System.Data.SqlClient.SqlParameter("@fs", SqlDbType.Image);
                myParameter.Value = fs;
                cmd.Parameters.Add(myParameter);
                try
                {
                    connection.Open();
                    int rows = cmd.ExecuteNonQuery();
                    return rows;
                }
                catch (System.Data.SqlClient.SqlException E)
                {
                    throw new Exception(E.Message);
                }
                finally
                {
                    cmd.Dispose();
                    connection.Close();
                }
            }
        }

        /// <summary>
        /// 执行一条计算查询结果语句，返回查询结果（object）。
        /// </summary>
        /// <param name="SQLString">计算查询结果语句</param>
        /// <returns>查询结果（object）</returns>
        public static object GetSingle(string SQLString)
        {
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                using (SqlCommand cmd = new SqlCommand(SQLString, connection))
                {
                    try
                    {
                        connection.Open();
                        object obj = cmd.ExecuteScalar();
                        if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
                        {
                            return 0;
                        }
                        else
                        {
                            return obj;
                        }
                    }
                    catch (System.Data.SqlClient.SqlException e)
                    {
                        connection.Close();
                        throw new Exception(e.Message);
                    }
                }
            }
        }
        /// <summary>
        /// 执行查询语句，返回SqlDataReader
        /// </summary>
        /// <param name="strSQL">查询语句</param>
        /// <returns>SqlDataReader</returns>
        public static SqlDataReader ExecuteReader(string strSQL)
        {
            SqlConnection conn = new SqlConnection(connectionString);
            SqlCommand cmd = new SqlCommand();
            try
            {
                conn.Open();
                cmd.CommandType = CommandType.Text;
                cmd.CommandText = strSQL;
                cmd.Connection = conn;
                
                SqlDataReader myReader = cmd.ExecuteReader();
                return myReader;
            }
            catch (System.Data.SqlClient.SqlException e)
            {
                throw new Exception(e.Message);
            }

        }
        /// <summary>
        /// 执行查询语句，返回DataSet
        /// </summary>
        /// <param name="SQLString">查询语句</param>
        /// <returns>DataSet</returns>
        public static DataSet Query(string SQLString)
        {
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                DataSet ds = new DataSet();
                try
                {
                    connection.Open();
                    SqlDataAdapter command = new SqlDataAdapter(SQLString, connection);
                    command.Fill(ds, "ds");
                }
                catch (System.Data.SqlClient.SqlException ex)
                {
                    throw new Exception(ex.Message);
                }
                return ds;
            }
        }


        #endregion

这些加进去也行。

[MXY169]

好多地方看不懂啊 。。。。。。我先慢慢研究会

[q107770540]

这个GOOGLE 里已经有很多完善的dbhelp.cs了吧...