C#中的根据实体增删改操作

在日常操作中，我们经常会对一些数据进行批量更新，

我在使用EF的时候，没有找到比较好的批量更新的解决方案，

便参考了张占岭前辈的博客，整合了这么一个简略版的使用实体类生成数据库增删改SQL的操作类

在进行更新和删除的时候，会针对的主键进行更新或者删除，所以我们需要给实体类用于主键的字段进行一个特性的标识

下面贴上代码，有不足或者错误之处希望大家多多指正

  /// <summary>
    /// 根据实体来生成批量新增、修改、删除的Sql语句
    /// 在Update和Delete
    /// </summary>
    /// <typeparam name="TEntity">实体</typeparam>
    public class EntityToSQL<TEntity> where TEntity : class
    {

        #region 根据集合获取SQL语句

        /// <summary>
        /// 执行SQL，根据SQL操作的类型
        /// </summary>
        /// <typeparam name="TEntity"></typeparam>
        /// <param name="list"></param>
        /// <param name="sqlType"></param>
        /// <returns></returns>
        /// </summary>
        /// <param name="list"></param>
        /// <param name="sqlType"></param>
        /// <returns></returns>
        public static string GetSql(IEnumerable<TEntity> list, SqlType sqlType)
        {
            return GetSql(list, sqlType, null);
        }

        /// <summary>
        /// 执行SQL，根据SQL操作的类型
        /// </summary>
        /// <typeparam name="TEntity"></typeparam>
        /// <param name="list"></param>
        /// <param name="sqlType"></param>
        /// <returns></returns>
        public static string GetSql(IEnumerable<TEntity> list, SqlType sqlType, params string[] fieldParams)
        {
            var sqlstr = new StringBuilder();
            switch (sqlType)
            {
                case SqlType.Insert:
                    list.ToList().ForEach(i =>
                    {
                        Tuple<string, object[]> sql = CreateInsertSql(i);
                        sqlstr.AppendFormat(sql.Item1, sql.Item2);
                    });
                    break;
                case SqlType.Update:
                    list.ToList().ForEach(i =>
                    {
                        Tuple<string, object[]> sql = CreateUpdateSql(i, fieldParams);
                        sqlstr.AppendFormat(sql.Item1, sql.Item2);
                    });
                    break;
                case SqlType.Delete:
                    list.ToList().ForEach(i =>
                    {
                        Tuple<string, object[]> sql = CreateDeleteSql(i);
                        sqlstr.AppendFormat(sql.Item1, sql.Item2);
                    });
                    break;
                default:
                    throw new ArgumentException("请输入正确的参数");
            }
            return sqlstr.ToString();
        }

        #endregion

        #region 构建Update语句串

        /// <summary>
        /// 构建Update语句串
        /// 注意：如果本方法过滤了int,decimal类型更新为０的列，如果希望更新它们需要指定FieldParams参数
        /// </summary>
        /// <param name="entity">实体列表</param>
        /// <param name="fieldParams">要更新的字段</param>
        /// <returns></returns>
        private static Tuple<string, object[]> CreateUpdateSql(TEntity entity, params string[] fieldParams)
        {
            if (entity == null)
                throw new ArgumentException("数据库实体不能为空");
            List<string> pkList = GetPrimaryKeyName();

            var entityType = entity.GetType();
            var tableFields = new List<PropertyInfo>();
            if (fieldParams != null && fieldParams.Count() > )
            {
                tableFields = entityType.GetProperties().Where(i => fieldParams.Contains(i.Name, StringComparer.OrdinalIgnoreCase)).ToList();
            }
            else
            {
                tableFields = entityType.GetProperties().Where(i =>
                              !pkList.Contains(i.Name)
                              && i.GetValue(entity, null) != null
                              && !i.PropertyType.IsEnum
                              && !(i.PropertyType == typeof(ValueType) && Convert.ToInt64(i.GetValue(entity, null)) == )
                              && !(i.PropertyType == typeof(DateTime) && Convert.ToDateTime(i.GetValue(entity, null)) == DateTime.MinValue)
                              && i.PropertyType != typeof(EntityState)
                              && i.GetCustomAttributes(false).Where(j => j.GetType() == typeof(NavigationAttribute)) != null//过滤导航属性
                              && (i.PropertyType.IsValueType || i.PropertyType == typeof(string))
                              ).ToList();
            }
            //过滤主键，航行属性，状态属性等
            if (pkList == null || pkList.Count() == )
                throw new ArgumentException("表实体没有主键");
            var arguments = new List<object>();
            var builder = new StringBuilder();

            foreach (var change in tableFields)
            {
                if (pkList.Contains(change.Name))
                    continue;
                if (arguments.Count != )
                    builder.Append(", ");
                builder.Append(change.Name + " = {" + arguments.Count + "}");
                if (change.PropertyType == typeof(string)
                    || change.PropertyType == typeof(DateTime)
                    || change.PropertyType == typeof(DateTime?)
                    || change.PropertyType == typeof(bool?)
                    || change.PropertyType == typeof(bool))
                    arguments.Add("'" + change.GetValue(entity, null).ToString().Replace("'", "char(39)") + "'");
                else
                    arguments.Add(change.GetValue(entity, null));
            }

            if (builder.Length == )
                throw new Exception("没有任何属性进行更新");

            builder.Insert(, " UPDATE " + string.Format("[{0}]", entityType.Name) + " SET ");

            builder.Append(" WHERE ");
            bool firstPrimaryKey = true;

            foreach (var primaryField in pkList)
            {
                if (firstPrimaryKey)
                    firstPrimaryKey = false;
                else
                    builder.Append(" AND ");

                object val = entityType.GetProperty(primaryField).GetValue(entity, null);
                Type pkType = entityType.GetProperty(primaryField).GetType();
                builder.Append(GetEqualStatment(primaryField, arguments.Count, pkType));
                arguments.Add(val);
            }
            return new Tuple<string, object[]>(builder.ToString(), arguments.ToArray());

        }

        #endregion

        #region 构建Insert语句串

        /// <summary>
        /// 构建Insert语句串
        /// 主键为自增时，如果主键值为0，我们将主键插入到SQL串中
        /// </summary>
        /// <typeparam name="TEntity"></typeparam>
        /// <param name="entity"></param>
        /// <returns></returns>
        private static Tuple<string, object[]> CreateInsertSql(TEntity entity)
        {
            if (entity == null)
                throw new ArgumentException("数据库实体不能为空");

            Type entityType = entity.GetType();
            var table = entityType.GetProperties().Where(i => i.PropertyType != typeof(EntityKey)
                 && i.PropertyType != typeof(EntityState)
                 && i.Name != "IsValid"
                 && i.GetValue(entity, null) != null
                 && !i.PropertyType.IsEnum
                 && i.GetCustomAttributes(false).Where(j => j.GetType() == typeof(NavigationAttribute)) != null
                 && (i.PropertyType.IsValueType || i.PropertyType == typeof(string))).ToArray();//过滤主键，航行属性，状态属性等

            var pkList = new List<string>();
            if (GetPrimaryKey() != null)//有时主键可能没有设计，这对于添加操作是可以的
                pkList = GetPrimaryKeyName();
            var arguments = new List<object>();
            var fieldbuilder = new StringBuilder();
            var valuebuilder = new StringBuilder();

            fieldbuilder.Append(" INSERT INTO " + string.Format("[{0}]", entityType.Name) + " (");

            foreach (var member in table)
            {
                if (pkList.Contains(member.Name) && Convert.ToString(member.GetValue(entity, null)) == "")
                    continue;
                object value = member.GetValue(entity, null);
                if (value != null)
                {
                    if (arguments.Count != )
                    {
                        fieldbuilder.Append(", ");
                        valuebuilder.Append(", ");
                    }

                    fieldbuilder.Append(member.Name);
                    if (member.PropertyType == typeof(string)
                        || member.PropertyType == typeof(DateTime)
                        || member.PropertyType == typeof(DateTime?)
                        || member.PropertyType == typeof(Boolean?)
                        || member.PropertyType == typeof(Boolean)
                        )
                        valuebuilder.Append("'{" + arguments.Count + "}'");
                    else
                        valuebuilder.Append("{" + arguments.Count + "}");
                    if (value is string)
                        value = value.ToString().Replace("'", "char(39)");
                    arguments.Add(value);

                }
            }

            fieldbuilder.Append(") Values (");
            fieldbuilder.Append(valuebuilder.ToString());
            fieldbuilder.Append(");");
            return new Tuple<string, object[]>(fieldbuilder.ToString(), arguments.ToArray());
        }

        #endregion

        #region 构建Delete语句串

        /// <summary>
        /// 构建Delete语句串
        /// </summary>
        /// <typeparam name="TEntity"></typeparam>
        /// <param name="entity"></param>
        /// <returns></returns>
        private static Tuple<string, object[]> CreateDeleteSql(TEntity entity)
        {
            if (entity == null)
                throw new ArgumentException("数据库实体不能为空");

            Type entityType = entity.GetType();
            List<string> pkList = GetPrimaryKeyName();
            if (pkList == null || pkList.Count == )
                throw new ArgumentException("表实体没有主键");

            var arguments = new List<object>();
            var builder = new StringBuilder();
            builder.Append(" Delete from " + string.Format("[{0}]", entityType.Name));

            builder.Append(" WHERE ");
            bool firstPrimaryKey = true;

            foreach (var primaryField in pkList)
            {
                if (firstPrimaryKey)
                    firstPrimaryKey = false;
                else
                    builder.Append(" AND ");

                Type pkType = entityType.GetProperty(primaryField).GetType();
                object val = entityType.GetProperty(primaryField).GetValue(entity, null);
                builder.Append(GetEqualStatment(primaryField, arguments.Count, pkType));
                arguments.Add(val);
            }
            return new Tuple<string, object[]>(builder.ToString(), arguments.ToArray());
        }

        #endregion

        #region 准备参数

        /// <summary>
        /// 获取Where条件
        /// </summary>
        /// <param name="fieldName"></param>
        /// <param name="paramId"></param>
        /// <param name="pkType"></param>
        /// <returns></returns>
        private static string GetEqualStatment(string fieldName, int paramId, Type pkType)
        {
            if (pkType.IsValueType)
                return string.Format("{0} = {1}", fieldName, GetParamTag(paramId));
            return string.Format("{0} = '{1}'", fieldName, GetParamTag(paramId));
        }

        private static string GetParamTag(int paramId)
        {
            return "{" + paramId + "}";
        }

        /// <summary>
        /// 获取标识为主键或者导航属性的属性
        /// </summary>
        /// <returns></returns>
        private static List<PropertyInfo> GetPrimaryKey()
        {
            Type entityType = typeof(TEntity);
            var retu = entityType.GetProperties().Where(x =>
            x.GetCustomAttributes().Where(j => j.GetType() == typeof(NavigationAttribute)).Count() > );
            if (retu != null && retu.Count() > )
                return retu.ToList();
            return null;
        }

        /// <summary>
        /// 获取特性的名字
        /// </summary>
        /// <returns></returns>
        private static List<string> GetPrimaryKeyName()
        {
            List<string> resu = new List<string>();
            List<PropertyInfo> list = GetPrimaryKey();
            if (list != null && list.Count > )
                resu = list.Select(x => x.Name).ToList();
            return resu;
        }

        #endregion

    }

    /// <summary>
    /// 属性的导航属性（用于标识实体的主键）
    /// </summary>
    public class NavigationAttribute : Attribute
    {

    }

    /// <summary>
    /// SQL操作类型
    /// </summary>
    public enum SqlType
    {
        Insert,
        Update,
        Delete,
    }

参考：

https://www.cnblogs.com/lori/p/4040951.html