实体类与DataTable互换

Posted 2020-09-19 爱睡觉的程序猿

 /// <summary>
        /// 实体类转换成DataTable
        /// </summary>
        /// <param name="modelList">实体类列表</param>
        /// <returns></returns>
        public DataTable FillDataTable(List<T> modelList)
        {
            if (modelList == null || modelList.Count == 0)
            {
                return null;
            }
            DataTable dt = CreateData(modelList[0]);

            foreach (T model in modelList)
            {
                DataRow dataRow = dt.NewRow();
                foreach (PropertyInfo propertyInfo in typeof(T).GetProperties())
                {
                    dataRow[propertyInfo.Name] = propertyInfo.GetValue(model, null);
                }
                dt.Rows.Add(dataRow);
            }
            return dt;
        }

        /// <summary>
        /// 根据实体类得到表结构
        /// </summary>
        /// <param name="model">实体类</param>
        /// <returns></returns>
        private DataTable CreateData(T model)
        {
            DataTable dataTable = new DataTable(typeof(T).Name);
            foreach (PropertyInfo propertyInfo in typeof(T).GetProperties())
            {
                dataTable.Columns.Add(new DataColumn(propertyInfo.Name, propertyInfo.PropertyType));
                
            }
            return dataTable;
        }

 /// <summary> 
        /// 填充对象列表：用DataTable填充实体类
        /// </summary> 
        public List<T> FillModel(DataTable dt)
        {
            if (dt == null || dt.Rows.Count == 0)
            {
                return null;
            }
            List<T> modelList = new List<T>();
            foreach (DataRow dr in dt.Rows)
            {
                //T model = (T)Activator.CreateInstance(typeof(T)); 
                T model = new T();
                for (int i = 0; i < dr.Table.Columns.Count; i++)
                {
                    PropertyInfo propertyInfo = model.GetType().GetProperty(dr.Table.Columns[i].ColumnName);
                    if (propertyInfo != null && dr[i] != DBNull.Value)
                        propertyInfo.SetValue(model, dr[i], null);
                }

                modelList.Add(model);
            }
            return modelList;
        }

 

 /// <summary>
        /// 将IDataReader类型转换为DataTable类型
        /// </summary>
        /// <param name="reader">IDataReader类型参数</param>
        /// <returns>DataTable</returns>
        public static DataTable GetDataTableFromIDataReader(IDataReader reader)
        {
            DataTable dt = new DataTable();
            bool init = false;
            dt.BeginLoadData();
            object[] vals = new object[0];
            while (reader.Read())
            {
                if (!init)
                {
                    init = true;
                    int fieldCount = reader.FieldCount;
                    for (int i = 0; i < fieldCount; ++i)
                    {
                        dt.Columns.Add(reader.GetName(i), reader.GetFieldType(i));
                    }
                    vals = new object[fieldCount - 1];
                }
                reader.GetValues(vals);
                dt.LoadDataRow(vals, true);
            }
            reader.Close();
            dt.EndLoadData();
            return dt;
        }