Question

C# WF窗体的DBhelp类怎么写.谢谢了，大神帮忙啊

这是关于C#WF窗体程序连接SQLite数据库的代码,, 怎么将这段代码封装到DBHelp类,然后在DBhelp类简单的数据库增删查改的代码怎么写 string datasource = "f:/sqlitesss.db"; if (!System.IO.File.Exists(datasource))//判断数据库是否存在 SQLiteConnection.CreateFile(datasource);//创建数据库文件 SQLiteConnection conn = new SQLiteConnection(); SQLiteConnectionStringBuilder connstr = new SQLiteConnectionStringBuilder(); connstr.DataSource = datasource; conn.ConnectionString = connstr.ToString(); conn.Open();

Answer 1

using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Data; using System.Data.SQLite; namespace DAL { static class SqlHelper { private static bool Conn = false; private static string ConnStr = @"Data Source=FileName;Pooling=true;FailIfMissing=false"; static SqlHelper() { Conn = TestConn(); } public static bool Update(string SQL, params SqlParameter[] SqlParameters) { bool Result = false; if (Conn) using (SQLiteConnection SqlConn = new SQLiteConnection(ConnStr)) { SqlConn.Open(); using (SQLiteCommand SqlCmd = new SQLiteCommand(SQL, SqlConn)) { if (SQLiteParameters != null) SqlCmd.Parameters.AddRange(SqlParameters); Result = SQLiteCmd.ExecuteNonQuery() > 0; } } return Result; } public static T Scalar<T>(string SQL, params SQLiteParameter[] SqlParameters) { object Result = null; if (Conn) using (SQLiteConnection SqlConn = new SQLiteConnection(ConnStr)) { SqlConn.Open(); using (SQLiteCommand SqlCmd = new SQLiteCommand(SQL, SqlConn)) { if (SQLiteParameters != null) SqlCmd.Parameters.AddRange(SqlParameters); Result = SqlCmd.ExecuteScalar(); } } return (Result != null) ? (T)Result : default(T); } public static DataTable Query(string SQL, params SQLiteParameter[] SqlParameters) { DataTable Result = null; if (Conn) using (SQLiteConnection SqlConn = new SQLiteConnection(ConnStr)) { SqlConn.Open(); using (SQLiteCommand SqlCmd = new SQLiteCommand(SQL, SqlConn)) { if (SqlParameters != null) SqlCmd.Parameters.AddRange(SqlParameters); using (SQLiteDataAdapter SqlAdap = new SQLiteDataAdapter(SqlCmd)) using (DataSet ds = new DataSet()) { SqlAdap.Fill(ds); Result = ds.Tables[0]; } } } return Result; } private static bool TestConn() { bool TestResult = false; try { using (SQLiteConnection SqlConn = new SQLiteConnection(ConnStr)) SqlConn.Open(); TestResult = true; } catch { TestResult = false; } return TestResult; } } }