C#的特点（c#的运用）

第一次写博客，想不到写什么好b（￣▽￣）d　，考虑的半天决定从sqlhelper开始，sqlhelper对程序员来说就像helloworld一样，很简单却又很重要，helloworld代表着程序员萌新第一次写代码，而sqlhelper则是初次接触数据库（不知道这种说法对不对）。

好了不废话了，下面直接上代码（无话可说了）：

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 public class SQLHelper { // 超时时间 private static int Timeout = 1000; // 数据库名称 public const String BestNet = "BestNet"; //存储过程名称 public const String UserInfoCURD = "UserInfoCURD"; // 数据库连接字符串 private static Dictionary<String, String> ConnStrs = new Dictionary<String, String>(); /// <summary> /// SQLServer操作类(静态构造函数) /// </summary> static SQLHelper() { ConnectionStringSettingsCollection configs = WebConfigurationManager.ConnectionStrings; foreach (ConnectionStringSettings config in configs) { ConnStrs.Add(config.Name, config.ConnectionString); } } /// <summary> /// 获取数据库连接 /// </summary> /// <param name="database">数据库(配置文件内connectionStrings的name)</param> /// <returns>数据库连接</returns> private static SqlConnection GetConnection(string database) { if (string.IsNullOrEmpty(database)) { throw new Exception("未设置参数：database"); } if (!ConnStrs.ContainsKey(database)) { throw new Exception("未找到数据库：" + database); } return new SqlConnection(ConnStrs[database]); } /// <summary> /// 获取SqlCommand /// </summary> /// <param name="conn">SqlConnection</param> /// <param name="transaction">SqlTransaction</param> /// <param name="cmdType">CommandType</param> /// <param name="sql">SQL</param> /// <param name="parms">SqlParameter数组</param> /// <returns></returns> private static SqlCommand GetCommand(SqlConnection conn, SqlTransaction transaction, CommandType cmdType, string sql, SqlParameter[] parms) { SqlCommand cmd = new SqlCommand(sql, conn); cmd.CommandType = cmdType; cmd.CommandTimeout = Timeout; if (transaction != null) cmd.Transaction = transaction; if (parms != null && parms.Length != 0) cmd.Parameters.AddRange(parms); return cmd; } /// <summary> /// 查询数据，返回DataTable /// </summary> /// <param name="database">数据库</param> /// <param name="sql">SQL语句或存储过程名</param> /// <param name="parms">参数</param> /// <param name="cmdType">查询类型(SQL语句/存储过程名)</param> /// <returns>DataTable</returns> public static DataTable QueryDataTable(string database, string sql, SqlParameter[] parms, CommandType cmdType) { if (string.IsNullOrEmpty(database)) { throw new Exception("未设置参数：database"); } if (string.IsNullOrEmpty(sql)) { throw new Exception("未设置参数：sql"); } try { using (SqlConnection conn = GetConnection(database)) { conn.Open(); using (SqlCommand cmd = GetCommand(conn, null, cmdType, sql, parms)) { using (SqlDataAdapter da = new SqlDataAdapter(cmd)) { DataTable dt = new DataTable(); da.Fill(dt); return dt; } } } } catch (SqlException ex) { System.Text.StringBuilder log = new System.Text.StringBuilder(); log.Append("查询数据出错："); log.Append(ex); throw new Exception(log.ToString()); } } /// <summary> /// 查询数据，返回DataSet /// </summary> /// <param name="database">数据库</param> /// <param name="sql">SQL语句或存储过程名</param> /// <param name="parms">参数</param> /// <param name="cmdType">查询类型(SQL语句/存储过程名)</param> /// <returns>DataSet</returns> public static DataSet QueryDataSet(string database, string sql, SqlParameter[] parms, CommandType cmdType) { if (string.IsNullOrEmpty(database)) { throw new Exception("未设置参数：database"); } if (string.IsNullOrEmpty(sql)) { throw new Exception("未设置参数：sql"); } try { using (SqlConnection conn = GetConnection(database)) { conn.Open(); using (SqlCommand cmd = GetCommand(conn, null, cmdType, sql, parms)) { using (SqlDataAdapter da = new SqlDataAdapter(cmd)) { DataSet ds = new DataSet(); da.Fill(ds); return ds; } } } } catch (SqlException ex) { System.Text.StringBuilder log = new System.Text.StringBuilder(); log.Append("查询数据出错："); log.Append(ex); throw new Exception(log.ToString()); } } /// <summary> /// 执行命令获取唯一值(第一行第一列) /// </summary> /// <param name="database">数据库</param> /// <param name="sql">SQL语句或存储过程名</param> /// <param name="parms">参数</param> /// <param name="cmdType">查询类型(SQL语句/存储过程名)</param> /// <returns>获取值</returns> public static object QueryScalar(string database, string sql, SqlParameter[] parms, CommandType cmdType) { if (string.IsNullOrEmpty(database)) { throw new Exception("未设置参数：database"); } if (string.IsNullOrEmpty(sql)) { throw new Exception("未设置参数：sql"); } try { using (SqlConnection conn = GetConnection(database)) { conn.Open(); using (SqlCommand cmd = GetCommand(conn, null, cmdType, sql, parms)) { return cmd.ExecuteScalar(); } } } catch (SqlException ex) { System.Text.StringBuilder log = new System.Text.StringBuilder(); log.Append("处理出错："); log.Append(ex); throw new Exception(log.ToString()); } } /// <summary> /// 执行命令更新数据 /// </summary> /// <param name="database">数据库</param> /// <param name="sql">SQL语句或存储过程名</param> /// <param name="parms">参数</param> /// <param name="cmdType">查询类型(SQL语句/存储过程名)</param> /// <returns>更新的行数</returns> public static int Execute(string database, string sql, SqlParameter[] parms, CommandType cmdType) { if (string.IsNullOrEmpty(database)) { throw new Exception("未设置参数：database"); } if (string.IsNullOrEmpty(sql)) { throw new Exception("未设置参数：sql"); } //返回(增删改)的更新行数 int count = 0; try { using (SqlConnection conn = GetConnection(database)) { conn.Open(); using (SqlCommand cmd = GetCommand(conn, null, cmdType, sql, parms)) { if (cmdType == CommandType.StoredProcedure) cmd.Parameters.AddWithValue("@RETURN_VALUE", "").Direction = ParameterDirection.ReturnValue; count = cmd.ExecuteNonQuery(); if (count <= 0) if (cmdType == CommandType.StoredProcedure) count = (int)cmd.Parameters["@RETURN_VALUE"].Value; } } } catch (SqlException ex) { System.Text.StringBuilder log = new System.Text.StringBuilder(); log.Append("处理出错："); log.Append(ex); throw new Exception(log.ToString()); } return count; } /// <summary> /// 查询数据，返回DataTable /// </summary> /// <param name="database">数据库</param> /// <param name="sql">SQL语句或存储过程名</param> /// <param name="cmdType">查询类型(SQL语句/存储过程名)</param> /// <param name="values">参数</param> /// <returns>DataTable</returns> public static DataTable QueryDataTable(string database, string sql, CommandType cmdType, IDictionary<string, object> values) { SqlParameter[] parms = DicToParams(values); return QueryDataTable(database, sql, parms, cmdType); } /// <summary> /// 执行存储过程查询数据，返回DataSet /// </summary> /// <param name="database">数据库</param> /// <param name="sql">SQL语句或存储过程名</param> /// <param name="cmdType">查询类型(SQL语句/存储过程名)</param> /// <param name="values">参数 /// <returns>DataSet</returns> public static DataSet QueryDataSet(string database, string sql, CommandType cmdType, IDictionary<string, object> values) { SqlParameter[] parms = DicToParams(values); return QueryDataSet(database, sql, parms, cmdType); } /// <summary> /// 执行命令获取唯一值(第一行第一列) /// </summary> /// <param name="database">数据库</param> /// <param name="sql">SQL语句或存储过程名</param> /// <param name="cmdType">查询类型(SQL语句/存储过程名)</param> /// <param name="values">参数</param> /// <returns>唯一值</returns> public static object QueryScalar(string database, string sql, CommandType cmdType, IDictionary<string, object> values) { SqlParameter[] parms = DicToParams(values); return QueryScalar(database, sql, parms, cmdType); } /// <summary> /// 执行命令更新数据 /// </summary> /// <param name="database">数据库</param> /// <param name="sql">SQL语句或存储过程名</param> /// <param name="cmdType">查询类型(SQL语句/存储过程名)</param> /// <param name="values">参数</param> /// <returns>更新的行数</returns> public static int Execute(string database, string sql, CommandType cmdType, IDictionary<string, object> values) { SqlParameter[] parms = DicToParams(values); return Execute(database, sql, parms, cmdType); } /// <summary> /// 创建参数 /// </summary> /// <param name="name">参数名</param> /// <param name="type">参数类型</param> /// <param name="size">参数大小</param> /// <param name="direction">参数方向(输入/输出)</param> /// <param name="value">参数值</param> /// <returns>新参数对象</returns> public static SqlParameter[] DicToParams(IDictionary<string, object> values) { if (values == null) return null; SqlParameter[] parms = new SqlParameter[values.Count]; int index = 0; foreach (KeyValuePair<string, object> kv in values) { SqlParameter parm = null; if (kv.Value == null) { parm = new SqlParameter(kv.Key, DBNull.Value); } else { Type t = kv.Value.GetType(); parm = new SqlParameter(kv.Key, NetToSql(kv.Value.GetType())); parm.Value = kv.Value; } parms[index++] = parm; } return parms; } /// <summary> /// .net类型转换为Sql类型 /// </summary> /// <param name="t">.net类型</param> /// <returns>Sql类型</returns> public static SqlDbType NetToSql(Type t) { SqlDbType dbType = SqlDbType.Variant; switch (t.Name) { case "Int16": dbType = SqlDbType.SmallInt; break; case "Int32": dbType = SqlDbType.Int; break; case "Int64": dbType = SqlDbType.BigInt; break; case "Single": dbType = SqlDbType.Real; break; case "Decimal": dbType = SqlDbType.Decimal; break; case "Byte[]": dbType = SqlDbType.VarBinary; break; case "Boolean": dbType = SqlDbType.Bit; break; case "String": dbType = SqlDbType.NVarChar; break; case "Char[]": dbType = SqlDbType.Char; break; case "DateTime": dbType = SqlDbType.DateTime; break; case "DateTime2": dbType = SqlDbType.DateTime2; break; case "DateTimeOffset": dbType = SqlDbType.DateTimeOffset; break; case "TimeSpan": dbType = SqlDbType.Time; break; case "Guid": dbType = SqlDbType.UniqueIdentifier; break; case "Xml": dbType = SqlDbType.Xml; break; case "Object": dbType = SqlDbType.Variant; break; } return dbType; } }

可以直接这样调用：

1 2 3 4 IDictionary<string, object> values = new Dictionary<string, object>(); values.Add("@UserName", UserName); values.Add("@PassWord", passWord); object Scalar = SQLHelper.QueryScalar(SQLHelper.BestNet, SQLHelper.UserInfoCURD, CommandType.StoredProcedure, values);