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public class ConvertHelper<T> where T : new()
    {
        private static Dictionary<Type, List<IPropertyConvertInfo>> ConvertInfo = new Dictionary<Type, List<IPropertyConvertInfo>>();

        public static ObservableCollection<T> ConvertToList(DataTable dt)
        {
            List<IPropertyConvertInfo> convertInfo = ConvertInfo.ContainsKey(typeof(T)) ? ConvertInfo[typeof(T)] : ParseConvertInfo(typeof(T));
            convertInfo = convertInfo.Where(v => dt.Columns.Contains(v.ColumnName)).ToList();
            return new ObservableCollection<T>(dt.Rows.Cast<DataRow>().Select(v => ConvertRowToModel(convertInfo, v)));
        }

        #region ==== Private Mothods ====

        private static List<IPropertyConvertInfo> ParseConvertInfo(Type modelType)
        {
            var properties = modelType.GetProperties().Where(v => v.IsDefined(typeof(ColumnNameAttribute), true))
                .Select(v => CreatePropertyConvertInfo(v)).ToList();
            ConvertInfo[modelType] = properties;
            return properties;
        }

        private static IPropertyConvertInfo CreatePropertyConvertInfo(PropertyInfo property)
        {
            IPropertyConvertInfo info = Activator.CreateInstance(typeof(PropertyConvertInfo<>).MakeGenericType(property.PropertyType)) as IPropertyConvertInfo;
            info.ColumnName = ((ColumnNameAttribute)property.GetCustomAttributes(typeof(ColumnNameAttribute), true)[0]).ColumnName;
            info.Property = property;
            return info;
        }

        private static T ConvertRowToModel(List<IPropertyConvertInfo> convertInfo, DataRow dataRow)
        {
            T model = new T();
            convertInfo.ForEach(v => v.DoFetchData(model, dataRow));
            return model;
        }

        #endregion ==== Private Mothods ====
    }

    internal interface IPropertyConvertInfo
    {
        PropertyInfo Property { get; set; }
        string ColumnName { get; set; }
        void DoFetchData(object model, DataRow row);
    }
    internal class PropertyConvertInfo<TProperty> : IPropertyConvertInfo
    {
        public PropertyInfo Property { get; set; }
        public string ColumnName { get; set; }

        public void DoFetchData(object model, DataRow row)
        {
            if (!(row[ColumnName] is DBNull))
            {
                if (row[ColumnName].GetType().ToString() == "System.Decimal")
                {
                    object value = Convert.ToDouble(row[ColumnName]);
                    Property.SetValue(model, value, null);
                }
                else if (row[ColumnName].GetType().ToString() =="System.SByte")
                {
                    object value = Convert.ToBoolean(row[ColumnName]);
                    Property.SetValue(model, value, null);
                }
                else
                {
                    Property.SetValue(model, row.Field<TProperty>(ColumnName), null);
                }
            }
        }
    }

 

posted on 2015-12-29 11:20  小寒  阅读(1548)  评论(0编辑  收藏  举报