ASP.NET Core3.0(一) --编写SqlHelper通用类连接数据库

上善若水 · 发表于 2024-2-29 08:14:44

一、新建一个.NET Core的工程文件

二、新建sqlHelper类

需要使用NuGet安装一下文件

System.Data.SqlClient
Microsoft.EntityFrameworkCore

以下代码较长，可以先粘贴复制，以后再仔细打磨

using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Options;
using System;
using System.Collections;
using System.Collections.Generic;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;
using System.IO;
using System.Linq;
using System.Web;
namespace CORE3.Common
{
/// 此类为抽象类，
/// 不允许实例化，在应用时直接调用即可
/// </summary>
public abstract class SqlHelper
{
//加载appsetting.json
static IConfiguration configuration = new ConfigurationBuilder()
.SetBasePath(Directory.GetCurrentDirectory())
.AddJsonFile("appsettings.json").Build();
/// <summary>
/// 数据库连接字符串，配置文件在appsettings.json文件中
/// </summary>
private static readonly string connectionString = configuration["DBSetting:ConnectString"];
private static Hashtable parmCache = Hashtable.Synchronized(new Hashtable());
#region//ExecteNonQuery方法
/// <summary>
///执行一个不需要返回值的SqlCommand命令，通过指定专用的连接字符串。
/// 使用参数数组形式提供参数列表
/// </summary>
/// <param name="connectionString">一个有效的数据库连接字符串</param>
/// <param name="cmdType">SqlCommand命令类型 (存储过程， T-SQL语句，等等。)</param>
/// <param name="cmdText">存储过程的名字或者 T-SQL 语句</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>返回一个数值表示此SqlCommand命令执行后影响的行数</returns>
public static int ExecteNonQuery(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
{
SqlCommand cmd = new SqlCommand();
using (SqlConnection conn = new SqlConnection(connectionString))
{
//通过PrePareCommand方法将参数逐个加入到SqlCommand的参数集合中
PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);
int val = cmd.ExecuteNonQuery();
//清空SqlCommand中的参数列表
cmd.Parameters.Clear();
return val;
}
}
/// <summary>
///执行一个不需要返回值的SqlCommand命令，通过指定专用的连接字符串。
/// 使用参数数组形式提供参数列表
/// </summary>
/// <param name="cmdType">SqlCommand命令类型 (存储过程， T-SQL语句，等等。)</param>
/// <param name="cmdText">存储过程的名字或者 T-SQL 语句</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>返回一个数值表示此SqlCommand命令执行后影响的行数</returns>
public static int ExecteNonQuery(CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
{
return ExecteNonQuery(connectionString, cmdType, cmdText, commandParameters);
}
/// <summary>
///存储过程专用
/// </summary>
/// <param name="cmdText">存储过程的名字</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>返回一个数值表示此SqlCommand命令执行后影响的行数</returns>
public static int ExecteNonQueryProducts(string cmdText, params SqlParameter[] commandParameters)
{
return ExecteNonQuery(CommandType.StoredProcedure, cmdText, commandParameters);
}
/// <summary>
///Sql语句专用
/// </summary>
/// <param name="cmdText">T_Sql语句</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>返回一个数值表示此SqlCommand命令执行后影响的行数</returns>
public static int ExecteNonQueryText(string cmdText, params SqlParameter[] commandParameters)
{
return ExecteNonQuery(CommandType.Text, cmdText, commandParameters);
}
#endregion
#region//GetTable方法
/// <summary>
/// 执行一条返回结果集的SqlCommand，通过一个已经存在的数据库连接
/// 使用参数数组提供参数
/// </summary>
/// <param name="connecttionString">一个现有的数据库连接</param>
/// <param name="cmdTye">SqlCommand命令类型</param>
/// <param name="cmdText">存储过程的名字或者 T-SQL 语句</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>返回一个表集合(DataTableCollection)表示查询得到的数据集</returns>
public static DataTableCollection GetTable(string connecttionString, CommandType cmdTye, string cmdText, SqlParameter[] commandParameters)
{
SqlCommand cmd = new SqlCommand();
DataSet ds = new DataSet();
using (SqlConnection conn = new SqlConnection(connecttionString))
{
PrepareCommand(cmd, conn, null, cmdTye, cmdText, commandParameters);
SqlDataAdapter adapter = new SqlDataAdapter();
adapter.SelectCommand = cmd;
adapter.Fill(ds);
}
DataTableCollection table = ds.Tables;
return table;
}
/// <summary>
/// 执行一条返回结果集的SqlCommand，通过一个已经存在的数据库连接
/// 使用参数数组提供参数
/// </summary>
/// <param name="cmdTye">SqlCommand命令类型</param>
/// <param name="cmdText">存储过程的名字或者 T-SQL 语句</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>返回一个表集合(DataTableCollection)表示查询得到的数据集</returns>
public static DataTableCollection GetTable(CommandType cmdTye, string cmdText, SqlParameter[] commandParameters)
{
return GetTable(connectionString, cmdTye, cmdText, commandParameters);
}
/// <summary>
/// 存储过程专用
/// </summary>
/// <param name="cmdText">存储过程的名字或者 T-SQL 语句</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表1</param>
/// <returns>返回一个表集合(DataTableCollection)表示查询得到的数据集</returns>
public static DataTableCollection GetTableProducts(string cmdText, SqlParameter[] commandParameters)
{
return GetTable(CommandType.StoredProcedure, cmdText, commandParameters);
}
/// <summary>
/// Sql语句专用
/// </summary>
/// <param name="cmdText"> T-SQL 语句</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>返回一个表集合(DataTableCollection)表示查询得到的数据集</returns>
public static DataTableCollection GetTableText(string cmdText, SqlParameter[] commandParameters)
{
return GetTable(CommandType.Text, cmdText, commandParameters);
}
#endregion
/// <summary>
/// 为执行命令准备参数
/// </summary>
/// <param name="cmd">SqlCommand 命令</param>
/// <param name="conn">已经存在的数据库连接</param>
/// <param name="trans">数据库事物处理</param>
/// <param name="cmdType">SqlCommand命令类型 (存储过程， T-SQL语句，等等。)</param>
/// <param name="cmdText">Command text，T-SQL语句例如 Select * from Products</param>
/// <param name="cmdParms">返回带参数的命令</param>
private static void PrepareCommand(SqlCommand cmd, SqlConnection conn, SqlTransaction trans, CommandType cmdType, string cmdText, SqlParameter[] cmdParms)
{
//判断数据库连接状态
if (conn.State != ConnectionState.Open)
conn.Open();
cmd.Connection = conn;
cmd.CommandText = cmdText;
//判断是否需要事物处理
if (trans != null)
cmd.Transaction = trans;
cmd.CommandType = cmdType;
if (cmdParms != null)
{
foreach (SqlParameter parm in cmdParms)
cmd.Parameters.Add(parm);
}
}
/// <summary>
/// Execute a SqlCommand that returns a resultset against the database specified in the connection string
/// using the provided parameters.
/// </summary>
/// <param name="connectionString">一个有效的数据库连接字符串</param>
/// <param name="cmdType">SqlCommand命令类型 (存储过程， T-SQL语句，等等。)</param>
/// <param name="cmdText">存储过程的名字或者 T-SQL 语句</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>A SqlDataReader containing the results</returns>
public static SqlDataReader ExecuteReader(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
{
SqlCommand cmd = new SqlCommand();
SqlConnection conn = new SqlConnection(connectionString);
// we use a try/catch here because if the method throws an exception we want to
// close the connection throw code, because no datareader will exist, hence the
// commandBehaviour.CloseConnection will not work
try
{
PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);
SqlDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
cmd.Parameters.Clear();
return rdr;
}
catch
{
conn.Close();
throw;
}
}
#region//ExecuteDataSet方法
/// <summary>
/// return a dataset
/// </summary>
/// <param name="connectionString">一个有效的数据库连接字符串</param>
/// <param name="cmdType">SqlCommand命令类型 (存储过程， T-SQL语句，等等。)</param>
/// <param name="cmdText">存储过程的名字或者 T-SQL 语句</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>return a dataset</returns>
public static DataSet ExecuteDataSet(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
{
SqlConnection conn = new SqlConnection(connectionString);
SqlCommand cmd = new SqlCommand();
try
{
PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);
SqlDataAdapter da = new SqlDataAdapter();
DataSet ds = new DataSet();
da.SelectCommand = cmd;
da.Fill(ds);
return ds;
}
catch
{
conn.Close();
throw;
}
}
/// <summary>
/// 返回一个DataSet
/// </summary>
/// <param name="cmdType">SqlCommand命令类型 (存储过程， T-SQL语句，等等。)</param>
/// <param name="cmdText">存储过程的名字或者 T-SQL 语句</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>return a dataset</returns>
public static DataSet ExecuteDataSet(CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
{
return ExecuteDataSet(connectionString, cmdType, cmdText, commandParameters);
}
/// <summary>
/// 返回一个DataSet
/// </summary>
/// <param name="cmdText">存储过程的名字</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>return a dataset</returns>
public static DataSet ExecuteDataSetProducts(string cmdText, params SqlParameter[] commandParameters)
{
return ExecuteDataSet(connectionString, CommandType.StoredProcedure, cmdText, commandParameters);
}
/// <summary>
/// 返回一个DataSet
/// </summary>
/// <param name="cmdText">T-SQL 语句</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>return a dataset</returns>
public static DataSet ExecuteDataSetText(string cmdText, params SqlParameter[] commandParameters)
{
return ExecuteDataSet(connectionString, CommandType.Text, cmdText, commandParameters);
}
public static DataView ExecuteDataSet(string connectionString, string sortExpression, string direction, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
{
SqlConnection conn = new SqlConnection(connectionString);
SqlCommand cmd = new SqlCommand();
try
{
PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);
SqlDataAdapter da = new SqlDataAdapter();
DataSet ds = new DataSet();
da.SelectCommand = cmd;
da.Fill(ds);
DataView dv = ds.Tables[0].DefaultView;
dv.Sort = sortExpression + " " + direction;
return dv;
}
catch
{
conn.Close();
throw;
}
}
#endregion
#region // ExecuteScalar方法
/// <summary>
/// 返回第一行的第一列
/// </summary>
/// <param name="cmdType">SqlCommand命令类型 (存储过程， T-SQL语句，等等。)</param>
/// <param name="cmdText">存储过程的名字或者 T-SQL 语句</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>返回一个对象</returns>
public static object ExecuteScalar(CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
{
return ExecuteScalar(SqlHelper.connectionString, cmdType, cmdText, commandParameters);
}
/// <summary>
/// 返回第一行的第一列存储过程专用
/// </summary>
/// <param name="cmdText">存储过程的名字</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>返回一个对象</returns>
public static object ExecuteScalarProducts(string cmdText, params SqlParameter[] commandParameters)
{
return ExecuteScalar(SqlHelper.connectionString, CommandType.StoredProcedure, cmdText, commandParameters);
}
/// <summary>
/// 返回第一行的第一列Sql语句专用
/// </summary>
/// <param name="cmdText">者 T-SQL 语句</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>返回一个对象</returns>
public static object ExecuteScalarText(string cmdText, params SqlParameter[] commandParameters)
{
return ExecuteScalar(SqlHelper.connectionString, CommandType.Text, cmdText, commandParameters);
}
/// <summary>
/// Execute a SqlCommand that returns the first column of the first record against the database specified in the connection string
/// using the provided parameters.
/// </summary>
/// <remarks>
/// e.g.:
/// Object obj = ExecuteScalar(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
/// </remarks>
/// <param name="connectionString">一个有效的数据库连接字符串</param>
/// <param name="cmdType">SqlCommand命令类型 (存储过程， T-SQL语句，等等。)</param>
/// <param name="cmdText">存储过程的名字或者 T-SQL 语句</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>An object that should be converted to the expected type using Convert.To{Type}</returns>
public static object ExecuteScalar(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
{
SqlCommand cmd = new SqlCommand();
using (SqlConnection connection = new SqlConnection(connectionString))
{
PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);
object val = cmd.ExecuteScalar();
cmd.Parameters.Clear();
return val;
}
}
/// <summary>
/// Execute a SqlCommand that returns the first column of the first record against an existing database connection
/// using the provided parameters.
/// </summary>
/// <remarks>
/// e.g.:
/// Object obj = ExecuteScalar(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
/// </remarks>
/// <param name="connectionString">一个有效的数据库连接字符串</param>
/// <param name="cmdType">SqlCommand命令类型 (存储过程， T-SQL语句，等等。)</param>
/// <param name="cmdText">存储过程的名字或者 T-SQL 语句</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>An object that should be converted to the expected type using Convert.To{Type}</returns>
public static object ExecuteScalar(SqlConnection connection, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
{
SqlCommand cmd = new SqlCommand();
PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);
object val = cmd.ExecuteScalar();
cmd.Parameters.Clear();
return val;
}
#endregion
/// <summary>
/// add parameter array to the cache将参数数组添加到缓存中
/// </summary>
/// <param name="cacheKey">Key to the parameter cache 参数缓存的键</param>
/// <param name="cmdParms">an array of SqlParamters to be cached 被缓存的参数数组</param>
public static void CacheParameters(string cacheKey, params SqlParameter[] commandParameters)
{
parmCache[cacheKey] = commandParameters;
}
/// <summary>
/// Retrieve cached parameters 检索缓存参数
/// </summary>
/// <param name="cacheKey">key used to lookup parameters 用于查找参数的键 </param>
/// <returns>Cached SqlParamters array 缓存参数数组</returns>
public static SqlParameter[] GetCachedParameters(string cacheKey)
{
SqlParameter[] cachedParms = (SqlParameter[])parmCache[cacheKey];
if (cachedParms == null)
return null;
SqlParameter[] clonedParms = new SqlParameter[cachedParms.Length];
for (int i = 0, j = cachedParms.Length; i < j; i++)
clonedParms[i] = (SqlParameter)((ICloneable)cachedParms[i]).Clone();
return clonedParms;
}
/// <summary>
/// 检查是否存在
/// </summary>
/// <param name="strSql">Sql语句</param>
/// <returns>bool结果</returns>
public static bool Exists(string strSql)
{
int cmdresult = Convert.ToInt32(ExecuteScalar(connectionString, CommandType.Text, strSql, null));
if (cmdresult == 0)
{
return false;
}
else
{
return true;
}
}
/// <summary>
/// 检查是否存在
/// </summary>
/// <param name="strSql">Sql语句</param>
/// <param name="cmdParms">参数</param>
/// <returns>bool结果</returns>
public static bool Exists(string strSql, params SqlParameter[] cmdParms)
{
int cmdresult = Convert.ToInt32(ExecuteScalar(connectionString, CommandType.Text, strSql, cmdParms));
if (cmdresult == 0)
{
return false;
}
else
{
return true;
}
}
}
}

复制代码

三、修改配置文件appsettings.json

{
"Logging": {
"IncludeScopes": false,
"LogLevel": {
"Default": "Warning"
}
},
"DBSetting": {
"ConnectString": "server=.;database=Test;uid=sa;pwd=root"
},
"AllowedHosts": "*"
}

复制代码

四、编写业务逻辑代码

using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Threading.Tasks;
using CORE3.Common;
using System.Data.SqlClient;
namespace CORE3.DLL
{
public class studentDLL
{
public DataTable GetData()
{
var sql = "select * from Student";
var data = SqlHelper.GetTable(CommandType.Text, sql, new SqlParameter[] { });
return data[0];
}
}
}

复制代码

五、前台展示

打开项目自动生成的Pages文件夹里的idex.cshtml文件

(1)在Index.cshtml.cs文件中，编写代码：

using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Threading.Tasks;
using CORE3.DLL;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.RazorPages;
using Microsoft.Extensions.Logging;
namespace CORE3.Pages
{
public class IndexModel : PageModel
{
private readonly ILogger<IndexModel> _logger;
public IndexModel(ILogger<IndexModel> logger)
{
_logger = logger;
}
public DataTable Data;
public void OnGet()
{
var studentDll = new studentDLL();
Data = studentDll.GetData();
}
}
}

复制代码

（2）在Index.cshtml文件中编写代码

@page
@model IndexModel
@{
ViewData["Title"] = "Home page";
}
@{
var data = Model.Data;
if (data.Rows.Count > 0)
{
for (int i = 0; i < data.Rows.Count; i++)
{
var row = data.Rows[i];
@row["ID"];
@row["Name"].ToString();
@row["Sex"];
}
}
}

复制代码

六、数据库文件

七、运行结果

来源：https://blog.csdn.net/weixin_43803985/article/details/103927766
免责声明：如果侵犯了您的权益，请联系站长，我们会及时删除侵权内容，谢谢合作！

		自动登录	找回密码
密码			会员注册

ASP.NET Core3.0(一) --编写SqlHelper通用类连接数据库

一、新建一个.NET Core的工程 文件

二、新建sqlHelper类

三、修改配置文件appsettings.json

四、编写业务逻辑代码

五、前台展示

六、数据库文件

七、运行结果

本帖子中包含更多资源

一、新建一个.NET Core的工程文件