本文定義了一個DBHelper類，是SQLite的。需要添加一個System.Data.SQLite的dll，可以到SQLite的官網下載。類的代碼如下

1 using System; 2 using System.Data; 3 using System.Data.SQLite; 4 using System.Configuration; 5 using System.Collections; 6 7 namespace Common 8 { 9 public abstract class SQLiteHelper 10 { 11 //Data Source=db file fullname 12 public static readonly string connectionstring = ConfigurationManager.AppSettings["connectionstring"]; 13 14 private static Hashtable parmCache = Hashtable.Synchronized(new Hashtable()); 15 16 public static int ExecuteNonQuery(string connectionstring, CommandType commandType, string commandText, params SQLiteParameter[] commandParameters) 17 { 18 SQLiteCommand cmd = new SQLiteCommand(); 19 using (SQLiteConnection cn=new SQLiteConnection(connectionstring)) 20 { 21 PrepareCommand(cmd, cn, null, commandType, commandText, commandParameters); 22 int result = cmd.ExecuteNonQuery(); 23 cmd.Parameters.Clear(); 24 return result; 25 } 26 } 27 28 public static int ExecuteNonQuery(SQLiteConnection connection, CommandType commandType, string commandText, params SQLiteParameter[] commandParameters) 29 { 30 SQLiteCommand cmd = new SQLiteCommand(); 31 32 PrepareCommand(cmd, connection, null, commandType, commandText, commandParameters); 33 int result = cmd.ExecuteNonQuery(); 34 cmd.Parameters.Clear(); 35 return result; 36 } 37 38 public static int ExecuteNonQuery(SQLiteTransaction trans, CommandType commandType, string commandText, params SQLiteParameter[] commandParameters) 39 { 40 SQLiteCommand cmd = new SQLiteCommand(); 41 42 PrepareCommand(cmd, trans.Connection, trans, commandType, commandText, commandParameters); 43 int result = cmd.ExecuteNonQuery(); 44 cmd.Parameters.Clear(); 45 return result; 46 } 47 48 public static SQLiteDataReader ExecuteReader(string connectionstring,CommandType commandType,string commandText,params SQLiteParameter [] commandParameters) 49 { 50 SQLiteCommand cmd = new SQLiteCommand(); 51 SQLiteConnection cn=new SQLiteConnection(connectionstring); 52 53 try 54 { 55 PrepareCommand(cmd, cn, null, commandType, commandText, commandParameters); 56 SQLiteDataReader result = null; 57 result = cmd.ExecuteReader(CommandBehavior.CloseConnection); 58 cmd.Parameters.Clear(); 59 return result; 60 } 61 catch 62 { 63 cn.Close(); 64 throw; 65 } 66 67 } 68 69 public static object ExecuteScalar(string connectionstring, CommandType commandType, string commandText, params SQLiteParameter[] commandParameters) 70 { 71 SQLiteCommand cmd = new SQLiteCommand(); 72 73 using (SQLiteConnection cn=new SQLiteConnection(connectionstring)) 74 { 75 PrepareCommand(cmd, cn, null, commandType, commandText, commandParameters); 76 object result = cmd.ExecuteScalar(); 77 cmd.Parameters.Clear(); 78 return result; 79 } 80 } 81 82 public static object ExecuteScalar(SQLiteConnection connection, CommandType commandType, string commandText, params SQLiteParameter[] commandParameters) 83 { 84 SQLiteCommand cmd = new SQLiteCommand(); 85 86 PrepareCommand(cmd, connection, null, commandType, commandText, commandParameters); 87 object result = cmd.ExecuteScalar(); 88 cmd.Parameters.Clear(); 89 return result; 90 } 91 92 public static void CacheParameters(string cacheKey, params SQLiteParameter[] commandParameters) 93 { 94 parmCache[cacheKey] = commandParameters; 95 } 96 97 public static SQLiteParameter[] GetCacheParameters(string cacheKey) 98 { 99 SQLiteParameter[] cacheParams = (SQLiteParameter[])parmCache[cacheKey]; 100 101 if (cacheParams == null) return null; 102 103 int cacheLength=cacheParams.Length; 104 SQLiteParameter[] cloneParams=new SQLiteParameter[cacheLength]; 105 106 for (int i = 0; i < cacheLength; i++) 107 cloneParams[i] = (SQLiteParameter)((ICloneable)cacheParams[i]).Clone(); 108 109 return cloneParams; 110 } 111 112 private static void PrepareCommand(SQLiteCommand command, SQLiteConnection connection, SQLiteTransaction trans, CommandType commandType, string commandText, SQLiteParameter[] commandParameters) 113 { 114 command.Connection = connection; 115 command.CommandType = commandType; 116 command.CommandText = commandText; 117 118 if (commandParameters != null) 119 command.Parameters.AddRange(commandParameters); 120 121 if (trans != null) 122 command.Transaction = trans; 123 124 if (connection.State != ConnectionState.Open) 125 connection.Open(); 126 } 127 } 128 }

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轉載于:https://www.cnblogs.com/HopeGi/archive/2013/02/08/2909404.html

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