DBHelper.cs是程序来连接数据的，也是一个程序必不可少的一个类(本人道行浅，目前这样认为)。由于一个程序基本写一次，容易忘记。所有写在这里备注
首先是引用
using System.Data; using System.Data.SqlClient; using System.Configuration;
然后代码：
（
conn.Close();
conn.Dispose();
cmd.Dispose();
这几个为了防患于未然也加上去了
）
public class DBHelper { private static readonly string strconnection = ConfigurationManager.ConnectionStrings["Conn"].ConnectionString; private static SqlConnection conn = new SqlConnection(strconnection); //创建给sqlreadr使用 public static SqlConnection GetConnection() { return conn; } /// <summary> /// 打开数据库链接 /// </summary> public static void OpenSqlConnection() { if (GetConnection().State == ConnectionState.Closed) { DBHelper.GetConnection().Open(); } } /// <summary> /// 关闭数据库链接 /// </summary> public static void ClosSqlConnection() { if (GetConnection().State == ConnectionState.Open) { DBHelper.GetConnection().Close(); } } /// <summary> /// 基础ExecuteNonQuery 方法 /// </summary> /// <param name="SQLString">执行的sql语句</param> /// <param name="type">是否执行存储过程·</param> /// <param name="prep">存储过程参数</param> /// <returns></returns> private static int ExecuteNonQuery(string SQLString, CommandType type, SqlParameter[] prep) { using (SqlConnection conn = new SqlConnection(strconnection)) { using (SqlCommand cmd = new SqlCommand(SQLString, conn)) { int r = 0; try { conn.Open(); cmd.CommandType = type; if (prep != null && prep.Length > 0) { foreach (SqlParameter p in prep) { cmd.Parameters.Add(p); } } r = cmd.ExecuteNonQuery(); } catch (System.Data.SqlClient.SqlException ex) { throw new Exception(ex.Message); } finally { conn.Close(); conn.Dispose(); cmd.Dispose(); } return r; } } } /// <summary> /// 基础datatable /// </summary> /// <param name="SQLString">执行的sql语句</param> /// <param name="type">是否执行存储过程·</param> /// <param name="prep">存储过程参数</param> /// <returns></returns> private static DataTable GetDataTable( string SQLString, CommandType type, SqlParameter[] prep) { using (SqlConnection conn = new SqlConnection(strconnection)) { using (SqlCommand cmd = new SqlCommand(SQLString, conn)) { SqlDataAdapter dap = null; DataTable dt = null; try { cmd.CommandType = type; if (prep != null && prep.Length > 0) { foreach (SqlParameter p in prep) { cmd.Parameters.Add(p); } } dap = new SqlDataAdapter(cmd); dt = new DataTable(); dap.Fill(dt); } catch (Exception ex) { } finally { conn.Close(); conn.Dispose(); cmd.Dispose(); } return dt; } } } /// <summary> /// 基础SqlDataReader /// </summary> /// <param name="SQLString">执行的sql语句</param> /// <param name="type">是否执行存储过程·</param> /// <param name="prep">存储过程参数</param> /// <returns></returns> private static SqlDataReader GetList(string SQLString, CommandType type, SqlParameter[] prep) { SqlCommand cmd = null; SqlDataReader dr = null; cmd = new SqlCommand(SQLString, conn); if (prep != null && prep.Length > 0) { cmd.Parameters.AddRange(prep); } cmd.CommandType = type; try { dr = cmd.ExecuteReader(); } catch (Exception ex) { } return dr; } //调用ExecuteNonQuery 方法 public static int ExecuteNonQuery(string SQLString, SqlParameter[] prep) { return ExecuteNonQuery(SQLString, CommandType.StoredProcedure, prep); } public static int ExecuteNonQuery(string SQLString) { return ExecuteNonQuery(SQLString, CommandType.Text, null); } //调用GetDataTable 方法 public static DataTable GetDataTable(string SQLString, SqlParameter[] prep) { return GetDataTable(SQLString, CommandType.StoredProcedure, prep); } public static DataTable GetDataTable(string SQLString) { return GetDataTable(SQLString, CommandType.Text, null); } //调用SqlDataReader 调用此方法需要先打开conn 使用完毕之后关闭conn public static SqlDataReader GetList(string SQLString, SqlParameter[] prep) { return GetList(SQLString, CommandType.StoredProcedure, prep); } public static SqlDataReader GetList(string SQLString) { return GetList(SQLString, CommandType.Text, null); } }
