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[ASP.net教程]开发C# .net时使用的数据库操作类SqlHelp.cs


练习开发WPF程序的时候,是这样写的,虽然很简单,相必很多新手会用到,所以拿来共享一下,

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Configuration;using System.Data.SqlClient;using System.Data;namespace HRMSys.DAL{  static class SqlHelper  {    public static readonly string connstr = ConfigurationManager.ConnectionStrings["connstr"].ConnectionString;    public static int ExecuteNonQuery(string sql,       params SqlParameter[] parameters)    {      using (SqlConnection conn = new SqlConnection(connstr))      {        conn.Open();        using (SqlCommand cmd = conn.CreateCommand())        {          cmd.CommandText = sql;          cmd.Parameters.AddRange(parameters);          return cmd.ExecuteNonQuery();        }      }    }    public static object ExecuteScalar(string sql,      params SqlParameter[] parameters)    {      using (SqlConnection conn = new SqlConnection(connstr))      {        conn.Open();        using (SqlCommand cmd = conn.CreateCommand())        {          cmd.CommandText = sql;          cmd.Parameters.AddRange(parameters);          return cmd.ExecuteScalar();        }      }    }    public static DataTable ExecuteDataTable(string sql,      params SqlParameter[] parameters)    {      using (SqlConnection conn = new SqlConnection(connstr))      {        conn.Open();        using (SqlCommand cmd = conn.CreateCommand())        {          cmd.CommandText = sql;          cmd.Parameters.AddRange(parameters);          DataSet dataset = new DataSet();          SqlDataAdapter adapter = new SqlDataAdapter(cmd);          adapter.Fill(dataset);          return dataset.Tables[0];        }      }    }    public static object FromDbValue(object value)    {      if (value == DBNull.Value)      {        return null;      }      else      {        return value;      }    }    public static object ToDbValue(object value)    {      if (value == null)      {        return DBNull.Value;      }      else      {        return value;      }    }  }}

  在开发.net NVelocity小程序的时候,稍稍修改了一下

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Configuration;using System.Data.SqlClient;using System.Data;namespace _06NVelocityCURD{  public static class SqlHelper  {    public static readonly string connstr =      ConfigurationManager.ConnectionStrings["connstr"].ConnectionString;    public static SqlConnection OpenConnection()    {      SqlConnection conn = new SqlConnection(connstr);      conn.Open();      return conn;    }    public static int ExecuteNonQuery(string cmdText,      params SqlParameter[] parameters)    {      using (SqlConnection conn = new SqlConnection(connstr))      {        conn.Open();        return ExecuteNonQuery(conn, cmdText, parameters);      }    }    public static object ExecuteScalar(string cmdText,      params SqlParameter[] parameters)    {      using (SqlConnection conn = new SqlConnection(connstr))      {        conn.Open();        return ExecuteScalar(conn, cmdText, parameters);      }    }    public static DataTable ExecuteDataTable(string cmdText,      params SqlParameter[] parameters)    {      using (SqlConnection conn = new SqlConnection(connstr))      {        conn.Open();        return ExecuteDataTable(conn, cmdText, parameters);      }    }    public static int ExecuteNonQuery(SqlConnection conn,string cmdText,      params SqlParameter[] parameters)    {      using (SqlCommand cmd = conn.CreateCommand())      {        cmd.CommandText = cmdText;        cmd.Parameters.AddRange(parameters);        return cmd.ExecuteNonQuery();      }    }    public static object ExecuteScalar(SqlConnection conn, string cmdText,      params SqlParameter[] parameters)    {      using (SqlCommand cmd = conn.CreateCommand())      {        cmd.CommandText = cmdText;        cmd.Parameters.AddRange(parameters);        return cmd.ExecuteScalar();      }    }    public static DataTable ExecuteDataTable(SqlConnection conn, string cmdText,      params SqlParameter[] parameters)    {      using (SqlCommand cmd = conn.CreateCommand())      {        cmd.CommandText = cmdText;        cmd.Parameters.AddRange(parameters);        using (SqlDataAdapter adapter = new SqlDataAdapter(cmd))        {          DataTable dt = new DataTable();          adapter.Fill(dt);          return dt;        }      }    }    public static object ToDBValue(this object value)    {      return value == null ? DBNull.Value : value;    }    public static object FromDBValue(this object dbValue)    {      return dbValue == DBNull.Value ? null : dbValue;    }  }}