标签：null ESS pac ase app catch abstract tostring nec
把做工程过程中重要的内容段备份一次，如下内容是关于C#封装的Sqlite访问类的内容，希望能对各位有一些用途。
using System;
using System.Collections;
using System.Collections.Specialized;
using System.Data;
using System.Configuration;
using System.Data.SQLite;
namespace DAL
{
internal abstract class DbHelperSQLite
{
public static string connectionString = "Data Source=" + AppDomain.CurrentDomain.BaseDirectory + @"dataleaf.db;Version=3;";
public DbHelperSQLite()
{
}
#region 公用方法
public static int GetMaxID(string FieldName, string TableName)
{
string strsql = "select max(" + FieldName + ")+1 from " + TableName;
object obj = GetSingle(strsql);
if (obj == null)
{
return 1;
}
else
{
return int.Parse(obj.ToString());
}
}
public static bool Exists(string strSql)
{
object obj = GetSingle(strSql);
int cmdresult;
if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
{
cmdresult = 0;
}
else
{
cmdresult = int.Parse(obj.ToString());
}
if (cmdresult == 0)
{
return false;
}
else
{
return true;
}
}
public static bool Exists(string strSql, params SQLiteParameter[] cmdParms)
{
object obj = GetSingle(strSql, cmdParms);
int cmdresult;
if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
{
cmdresult = 0;
}
else
{
cmdresult = int.Parse(obj.ToString());
}
if (cmdresult == 0)
{
return false;
}
else
{
return true;
}
}
#endregion
#region 执行简单SQL语句
public static int ExecuteSql(string SQLString)
{
using (SQLiteConnection connection = new SQLiteConnection(connectionString))
{
using (SQLiteCommand cmd = new SQLiteCommand(SQLString, connection))
{
try
{
connection.Open();
int rows = cmd.ExecuteNonQuery();
return rows;
}
catch (System.Data.SQLite.SQLiteException E)
{
connection.Close();
throw new Exception(E.Message);
}
}
}
}
public static void ExecuteSqlTran(ArrayList SQLStringList)
{
using (SQLiteConnection conn = new SQLiteConnection(connectionString))
{
conn.Open();
SQLiteCommand cmd = new SQLiteCommand();
cmd.Connection = conn;
SQLiteTransaction tx = conn.BeginTransaction();
cmd.Transaction = tx;
try
{
for (int n = 0; n < SQLStringList.Count; n++)
{
string strsql = SQLStringList[n].ToString();
if (strsql.Trim().Length > 1)
{
cmd.CommandText = strsql;
cmd.ExecuteNonQuery();
}
}
tx.Commit();
}
catch (System.Data.SQLite.SQLiteException E)
{
tx.Rollback();
throw new Exception(E.Message);
}
}
}
public static int ExecuteSql(string SQLString, string content)
{
using (SQLiteConnection connection = new SQLiteConnection(connectionString))
{
SQLiteCommand cmd = new SQLiteCommand(SQLString, connection);
SQLiteParameter myParameter = new SQLiteParameter("@content", DbType.String);
myParameter.Value = content;
cmd.Parameters.Add(myParameter);
try
{
connection.Open();
int rows = cmd.ExecuteNonQuery();
return rows;
}
catch (System.Data.SQLite.SQLiteException E)
{
throw new Exception(E.Message);
}
finally
{
cmd.Dispose();
connection.Close();
}
}
}
public static int ExecuteSqlInsertImg(string strSQL, byte[] fs)
{
using (SQLiteConnection connection = new SQLiteConnection(connectionString))
{
SQLiteCommand cmd = new SQLiteCommand(strSQL, connection);
SQLiteParameter myParameter = new SQLiteParameter("@fs", DbType.Binary);
myParameter.Value = fs;
cmd.Parameters.Add(myParameter);
try
{
connection.Open();
int rows = cmd.ExecuteNonQuery();
return rows;
}
catch (System.Data.SQLite.SQLiteException E)
{
throw new Exception(E.Message);
}
finally
{
cmd.Dispose();
connection.Close();
}
}
}
public static object GetSingle(string SQLString)
{
using (SQLiteConnection connection = new SQLiteConnection(connectionString))
{
using (SQLiteCommand cmd = new SQLiteCommand(SQLString, connection))
{
try
{
connection.Open();
object obj = cmd.ExecuteScalar();
if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
{
return null;
}
else
{
return obj;
}
}
catch (System.Data.SQLite.SQLiteException e)
{
connection.Close();
throw new Exception(e.Message);
}
}
}
}
public static SQLiteDataReader ExecuteReader(string strSQL)
{
SQLiteConnection connection = new SQLiteConnection(connectionString);
SQLiteCommand cmd = new SQLiteCommand(strSQL, connection);
try
{
connection.Open();
SQLiteDataReader myReader = cmd.ExecuteReader();
return myReader;
}
catch (System.Data.SQLite.SQLiteException e)
{
throw new Exception(e.Message);
}
}
public static DataSet Query(string SQLString)
{
using (SQLiteConnection connection = new SQLiteConnection(connectionString))
{
DataSet ds = new DataSet();
try
{
connection.Open();
SQLiteDataAdapter command = new SQLiteDataAdapter(SQLString, connection);
command.Fill(ds, "ds");
}
catch (System.Data.SQLite.SQLiteException ex)
{
throw new Exception(ex.Message);
}
return ds;
}
}
#endregion
#region 执行带参数的SQL语句
public static int ExecuteSql(string SQLString, params SQLiteParameter[] cmdParms)
{
using (SQLiteConnection connection = new SQLiteConnection(connectionString))
{
using (SQLiteCommand cmd = new SQLiteCommand())
{
try
{
PrepareCommand(cmd, connection, null, SQLString, cmdParms);
int rows = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
return rows;
}
catch (System.Data.SQLite.SQLiteException E)
{
throw new Exception(E.Message);
}
}
}
}
public static void ExecuteSqlTran(Hashtable SQLStringList)
{
using (SQLiteConnection conn = new SQLiteConnection(connectionString))
{
conn.Open();
using (SQLiteTransaction trans = conn.BeginTransaction())
{
SQLiteCommand cmd = new SQLiteCommand();
try
{
foreach (DictionaryEntry myDE in SQLStringList)
{
string cmdText = myDE.Key.ToString();
SQLiteParameter[] cmdParms = (SQLiteParameter[])myDE.Value;
PrepareCommand(cmd, conn, trans, cmdText, cmdParms);
int val = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
trans.Commit();
}
}
catch
{
trans.Rollback();
throw;
}
}
}
}
public static object GetSingle(string SQLString, params SQLiteParameter[] cmdParms)
{
using (SQLiteConnection connection = new SQLiteConnection(connectionString))
{
using (SQLiteCommand cmd = new SQLiteCommand())
{
try
{
PrepareCommand(cmd, connection, null, SQLString, cmdParms);
object obj = cmd.ExecuteScalar();
cmd.Parameters.Clear();
if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
{
return null;
}
else
{
return obj;
}
}
catch (System.Data.SQLite.SQLiteException e)
{
throw new Exception(e.Message);
}
}
}
}
public static SQLiteDataReader ExecuteReader(string SQLString, params SQLiteParameter[] cmdParms)
{
SQLiteConnection connection = new SQLiteConnection(connectionString);
SQLiteCommand cmd = new SQLiteCommand();
try
{
PrepareCommand(cmd, connection, null, SQLString, cmdParms);
SQLiteDataReader myReader = cmd.ExecuteReader();
cmd.Parameters.Clear();
return myReader;
}
catch (System.Data.SQLite.SQLiteException e)
{
throw new Exception(e.Message);
}
}
public static DataSet Query(string SQLString, params SQLiteParameter[] cmdParms)
{
using (SQLiteConnection connection = new SQLiteConnection(connectionString))
{
SQLiteCommand cmd = new SQLiteCommand();
PrepareCommand(cmd, connection, null, SQLString, cmdParms);
using (SQLiteDataAdapter da = new SQLiteDataAdapter(cmd))
{
DataSet ds = new DataSet();
try
{
da.Fill(ds, "ds");
cmd.Parameters.Clear();
}
catch (System.Data.SQLite.SQLiteException ex)
{
throw new Exception(ex.Message);
}
return ds;
}
}
}
private static void PrepareCommand(SQLiteCommand cmd, SQLiteConnection conn, SQLiteTransaction trans, string cmdText, SQLiteParameter[] cmdParms)
{
if (conn.State != ConnectionState.Open)
conn.Open();
cmd.Connection = conn;
cmd.CommandText = cmdText;
if (trans != null)
cmd.Transaction = trans;
if (cmdParms != null)
{
foreach (SQLiteParameter parm in cmdParms)
cmd.Parameters.Add(parm);
}
}
#endregion
}
}
标签：null ESS pac ase app catch abstract tostring nec
原文地址：https://www.cnblogs.com/lpypg/p/13064126.html
