【SQLite】SQLite中DateTime类型字段存取问题

1、如果直接存储DateTime.ToString()或DateTime.ToString("yy/MM/dd hh:mm:ss")（写DateTime.ToString("yy-MM-dd hh:mm:ss")会插入数据不成功），能成功插入数据并在SqliteDeveloper中显示正确时间，但从数据库查询时，会报错。

2、用DateTime.ToString("s")插入数据，能成功插入数据，但在SqliteDeveloper中全都显示1899/12/30，从数据库查询时，不会报错。

3、有人说把数据类型设为nvarchar。这样可以成功插入数据并读取，但碰到要用时间作为查询条件时，无法实现功能。可以看看这个帖子：https://bbs.csdn.net/topics/390302153

无奈只能选第二种方式。这问题也是蛮坑的。

-----------------更新-----------------

无语了，本来用DateTime.ToString("s")已经测试可以了，不知怎么的今天又发现还是提示无效的DateTime。
又是一通搜索。
原来只能用参数化的方式插入/修改数据，用sql拼接语句就不行。


Sqlite参数化查询：
https://www.cnblogs.com/kdp0213/p/8554032.html

我自己写的代码：

        /// <summary>
        /// 指定列插入数据
        /// </summary>
        public bool AddDatas1<T>(T testClass, string tableName)
        {
            string colStr = "";
            string tmpValueStr = "";

            Type t = testClass.GetType();//获得该类的Type
            foreach (PropertyInfo pi in t.GetProperties())
            {
                string name = pi.Name;
                if (name.ToLower() == "id")
                {
                    continue;
                }
                colStr += pi.Name + ",";
                tmpValueStr += "@" + pi.Name + ",";
            }
            colStr = colStr.Substring(0, colStr.LastIndexOf(',')); //删掉最后一个逗号
            tmpValueStr = tmpValueStr.Substring(0, tmpValueStr.LastIndexOf(','));

            string cmdStr = string.Format("insert into {0}({1}) values({2});", tableName, colStr, tmpValueStr);

            try
            {
                using (SQLiteCommand cmd = new SQLiteCommand(cmdStr, SQL_Conn))
                {
                    foreach (PropertyInfo pi in t.GetProperties())
                    {
                        string name = pi.Name;
                        if (name.ToLower() == "id")
                        {
                            continue;
                        }

                        DbType DBtype = DbType.String;
                        Type type = pi.PropertyType;
                        object value = pi.GetValue(testClass, null);//用GetValue获得值

                        if (type == typeof(DateTime))
                        {
                            DBtype = DbType.DateTime;
                        }
                        else if (type == typeof(bool))
                        {
                            DBtype = DbType.Boolean;
                            value = (((bool)value == true) ? 1 : 0);
                        }
                        else if (type == typeof(int))
                        {
                            DBtype = DbType.Int32;
                        }

                        if (value == null)
                        {
                            value = DBNull.Value;
                        }
                        cmd.Parameters.Add("@" + name, DBtype);//添加参数
                        cmd.Parameters["@" + name].Value = value;//为参数赋值
                    }
                    cmd.ExecuteNonQuery();
                    return true;
                }
            }
            catch(Exception ex)
            {
                return false;
            }
        }

        /// <summary>
        /// 修改整条数据
        /// </summary>
        /// <param name="testClass">类的实例</param>
        /// <param name="tableName">表名</param>
        /// <param name="mainKeyName">主键名</param>
        /// <param name="keyValue">主键值</param>
        /// <returns></returns>
        public bool ModifyData1<T>(T testClass, string tableName, string mainKeyName, string keyValue)
        {
            string colStr = "";
            string valueStr = "";

            Type t = testClass.GetType();//获得该类的Type
            foreach (PropertyInfo pi in t.GetProperties())
            {
                string name = pi.Name;
                if (name.ToLower() == "id")
                {
                    continue;
                }
                if (name == mainKeyName) //如果索引的键是字符串类型
                {
                    Type type = pi.PropertyType;
                    if (type == typeof(string))
                    {
                        keyValue = "'" + keyValue + "'";//如果索引的键是字符串类型 加上引号
                    }
                }
                colStr += pi.Name + "=@" + pi.Name + ",";
            }
            colStr = colStr.Substring(0, colStr.LastIndexOf(',')); //删掉最后一个逗号
            string cmdStr = string.Format("update {0} set {1} where {2}" + " = " + "{3};", tableName, colStr, mainKeyName, keyValue);
          
            try
            {
                using (SQLiteCommand cmd = new SQLiteCommand(cmdStr, SQL_Conn))
                {
                    foreach (PropertyInfo pi in t.GetProperties())
                    {
                        string name = pi.Name;
                        if (name.ToLower() == "id")
                        {
                            continue;
                        }

                        DbType DBtype = DbType.String;
                        Type type = pi.PropertyType;
                        object value = pi.GetValue(testClass, null);//用GetValue获得值

                        if (type == typeof(DateTime))
                        {
                            DBtype = DbType.DateTime;
                        }
                        else if (type == typeof(bool))
                        {
                            DBtype = DbType.Boolean;
                            value = (((bool)value == true) ? 1 : 0);
                        }
                        else if (type == typeof(int))
                        {
                            DBtype = DbType.Int32;
                        }

                        if (value == null)
                        {
                            value = DBNull.Value;
                        }
                        cmd.Parameters.Add("@" + name, DBtype);  //添加参数
                        cmd.Parameters["@" + name].Value = value;//为参数赋值
                    }
                    cmd.ExecuteNonQuery();
                    return true;
                }
            }
            catch(Exception ex)
            {
                return false;
            }
        }

如果插入数据需要返回自增ID：

        /// <summary>
        /// 指定列插入数据并获取自增长主键值
        /// </summary>
        public bool AddDatas<T>(T testClass, string tableName, out int id)
        {
            string colStr = "";
            string tmpValueStr = "";
            id = 0;
            Type t = testClass.GetType();//获得该类的Type
            foreach (PropertyInfo pi in t.GetProperties())
            {
                string name = pi.Name;
                if (name.ToLower() == "id")//主表主键不赋值
                {
                    continue;
                }
                colStr += pi.Name + ",";
                tmpValueStr += "@" + pi.Name + ",";
            }
            colStr = colStr.Substring(0, colStr.LastIndexOf(',')); //删掉最后一个逗号
            tmpValueStr = tmpValueStr.Substring(0, tmpValueStr.LastIndexOf(','));

            string cmdStr = string.Format("insert into {0}({1}) values({2});" + "select last_insert_rowid() from {0};", tableName, colStr, tmpValueStr);

            try
            {
                using (SQLiteCommand cmd = new SQLiteCommand(cmdStr, SQL_Conn))
                {
                    foreach (PropertyInfo pi in t.GetProperties())
                    {
                        string name = pi.Name;
                        if (name.ToLower() == "id")
                        {
                            continue;
                        }

                        DbType DBtype = DbType.String;
                        Type type = pi.PropertyType;
                        object value = pi.GetValue(testClass, null);//用GetValue获得值

                        if (type == typeof(DateTime))
                        {
                            DBtype = DbType.DateTime;
                        }
                        else if (type == typeof(bool))
                        {
                            DBtype = DbType.Boolean;
                            value = (((bool)value == true) ? 1 : 0);
                        }
                        else if (type == typeof(int))
                        {
                            DBtype = DbType.Int32;
                        }

                        if (value == null)
                        {
                            value = DBNull.Value;
                        }
                        cmd.Parameters.Add("@" + name, DBtype);  //添加参数
                        cmd.Parameters["@" + name].Value = value;//为参数赋值
                    }
                    DbDataReader reader = cmd.ExecuteReader();
                    if (reader.Read())
                    {
                        id = int.Parse(reader[0].ToString());
                        reader.Close();
                        return true;
                    }
                    else
                    {
                        id = 0;
                        return false;
                    }
                }
            }
            catch (Exception ex)
            {
                return false;
            }
        }