list转datatable

1、datatable转list

/// <summary>
    /// 将泛类型集合List类转换成DataTable
    /// </summary>
    /// <param name="list">泛类型集合</param>
    /// <returns></returns>
    public static DataTable ListToDataTable<T>(List<T> entitys)
    {
        //检查实体集合不能为空
        if (entitys == null || entitys.Count < 1)
        {
            throw new Exception("需转换的集合为空");
        }
        //取出第一个实体的所有Propertie
        Type entityType = entitys[0].GetType();
        PropertyInfo[] entityProperties = entityType.GetProperties();

        //生成DataTable的structure
        //生产代码中，应将生成的DataTable结构Cache起来，此处略
        DataTable dt = new DataTable();
        for (int i = 0; i < entityProperties.Length; i++)
        {
            //dt.Columns.Add(entityProperties[i].Name, entityProperties[i].PropertyType);
            dt.Columns.Add(entityProperties[i].Name);
        }
        //将所有entity添加到DataTable中
        foreach (object entity in entitys)
        {
            //检查所有的的实体都为同一类型
            if (entity.GetType() != entityType)
            {
                throw new Exception("要转换的集合元素类型不一致");
            }
            object[] entityValues = new object[entityProperties.Length];
            for (int i = 0; i < entityProperties.Length; i++)
            {
                entityValues[i] = entityProperties[i].GetValue(entity, null);
            }
            dt.Rows.Add(entityValues);
        }
        return dt;
    }

 

2、

public static class DataTableHelper
    {
        public static DataTable ConvertTo<T>(IList<T> list)
        {
            DataTable table = CreateTable<T>();
            Type entityType = typeof(T);
            PropertyDescriptorCollection properties = TypeDescriptor.GetProperties(entityType);
            foreach (T item in list)
            {
                DataRow row = table.NewRow();
                foreach (PropertyDescriptor prop in properties)
                    row[prop.Name] = prop.GetValue(item);
                table.Rows.Add(row);
            }
            return table;
        }

        public static IList<T> ConvertTo<T>(IList<DataRow> rows)
        {
            IList<T> list = null;
            if (rows != null)
            {
                list = new List<T>();
                foreach (DataRow row in rows)
                {
                    T item = CreateItem<T>(row);
                    list.Add(item);
                }
            }
            return list;
        }

        public static IList<T> ConvertTo<T>(DataTable table)
        {
            if (table == null)
                return null;

            List<DataRow> rows = new List<DataRow>();
            foreach (DataRow row in table.Rows)
                rows.Add(row);

            return ConvertTo<T>(rows);
        }

        //Convert DataRow into T Object
        public static T CreateItem<T>(DataRow row)
        {
            string columnName;
            T obj = default(T);
            if (row != null)
            {
                obj = Activator.CreateInstance<T>();
                foreach (DataColumn column in row.Table.Columns)
                {
                    columnName = column.ColumnName;
                    //Get property with same columnName
                    PropertyInfo prop = obj.GetType().GetProperty(columnName);
                    try
                    {
                        //Get value for the column
                        object value = (row[columnName].GetType() == typeof(DBNull))
                        ? null : row[columnName];
                        //Set property value
                        if (prop.CanWrite)    //判断其是否可写
                            prop.SetValue(obj, value, null);
                    }
                    catch
                    {
                        throw;
                        //Catch whatever here
                    }
                }
            }
            return obj;
        }

        public static DataTable CreateTable<T>()
        {
            Type entityType = typeof(T);
            DataTable table = new DataTable(entityType.Name);
            PropertyDescriptorCollection properties = TypeDescriptor.GetProperties(entityType);

            foreach (PropertyDescriptor prop in properties)
                table.Columns.Add(prop.Name, prop.PropertyType);

            return table;
        }
    }