ASP.NET动态数据过滤

沮丧并采取直接的路线。如果没有更好的解决方案……好吧，那么微软在这方面做得很差：

    
      public class QueryableFilterRepeater : System.Web.DynamicData.QueryableFilterRepeater
    {
        private static readonly FieldInfo FiltersField = typeof(System.Web.DynamicData.QueryableFilterRepeater).GetField(“_filters”, BindingFlags.Instance | BindingFlags.NonPublic);
        private static readonly FieldInfo DataSourceField = typeof(System.Web.DynamicData.QueryableFilterRepeater).GetField(“_dataSource”, BindingFlags.Instance | BindingFlags.NonPublic);
        private static readonly MethodInfo FilterInitializeMethod = typeof(DynamicFilter).GetMethod(“Initialize”, BindingFlags.Instance | BindingFlags.NonPublic);
        private static readonly PropertyInfo FilterContextProperty = typeof(DynamicFilter).GetProperty(“Context”, BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.DeclaredOnly);
        private static readonly MethodInfo PageInitCompleteMethod = typeof(System.Web.DynamicData.QueryableFilterRepeater).GetMethod(“Page_InitComplete”, BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.DeclaredOnly);
        private static readonly EventInfo InitCompleteEvent = typeof(Page).GetEvent(“InitComplete”);
    private readonly List<DynamicFilter> filters;
    private int filterCount;
    private bool initialized;
    public IEnumerable<DynamicFilter> Filters
    {
        get { return filters; }
    }
    public QueryableFilterRepeater()
    {
        filters = (List<DynamicFilter>)FiltersField.GetValue(this);
    }
    private IQueryableDataSource DataSource
    {
        get { return DataSourceField.GetValue(this) as IQueryableDataSource; }
    }
    protected override void OnInit(EventArgs e)
    {
        base.OnInit(e);
        InitCompleteEvent.RemoveEventHandler(Page, Delegate.CreateDelegate(typeof(EventHandler), this, PageInitCompleteMethod));
        Page.InitComplete += new EventHandler(Page_InitComplete);
    }
    protected override void OnLoad(EventArgs e)
    {
        filters.Select((f, i) => new { f, i }).Where(x => x.i > filterCount - 1).ToList().ForEach(x => filters.Remove(x.f));
        Controls.OfType<Control>().Select((c, i) => new { c, i }).Where(x => x.i > filterCount - 1).ToList().ForEach(x => Controls.Remove(x.c));
        base.OnLoad(e);
    }
    private void Page_InitComplete(object sender, EventArgs e)
    {
        if (!initialized)
        {
            Controls.Clear();
            filters.Clear();
            MetaTable metaTable = DataSource.GetMetaTable();
            int num = 0;
            foreach (MetaColumn column in metaTable.Columns)
            {
                string filterUIHint = GetFilterUIHint(column);
                if (filterUIHint == null) continue;
                var filterRepeaterItem = new FilterRepeaterItem();
                filterRepeaterItem.DataItemIndex = num;
                filterRepeaterItem.DisplayIndex = num;
                FilterRepeaterItem container = filterRepeaterItem;
                num++;
                ItemTemplate.InstantiateIn(container);
                Controls.Add(container);
                var dynamicFilter = container.FindControl(DynamicFilterContainerId) as DynamicFilter;
                if (dynamicFilter == null)
                {
                    throw new InvalidOperationException();
                }
                FilterContextProperty.SetValue(dynamicFilter, new HttpContextWrapper(Context), null);
                dynamicFilter.DataField = column.Name;
                container.DataItem = column;
                container.DataBind();
                container.DataItem = null;
                dynamicFilter.FilterUIHint = filterUIHint;
                filters.Add(dynamicFilter);
                filterCount++;
            }
            filters.ForEach(f => FilterInitializeMethod.Invoke(f, new[] { DataSource }));
            initialized = true;
        }
    }
    private string GetFilterUIHint(MetaColumn column)
    {
        if (GetUnderlyingType(column.ColumnType) == typeof(string))
        {
            return "String";
        }
        if (GetUnderlyingType(column.ColumnType) == typeof(bool))
        {
            return "Boolean";
        }
        if (GetUnderlyingType(column.ColumnType).IsEnum)
        {
            return "Enumeration";
        }
        if (GetUnderlyingType(column.ColumnType) == typeof(DateTime))
        {
            return "DateTime";
        }
        if (column is MetaForeignKeyColumn)
        {
            return "ForeignKey";
        }
        if (column is MetaChildrenColumn)
        {
            return "Children";
        }
        return null;
    }
    private Type GetUnderlyingType(Type type)
    {
        return Nullable.GetUnderlyingType(type) ?? type;
    }
    // Nested Types
    #region Nested type: FilterRepeaterItem
    private class FilterRepeaterItem : Control, IDataItemContainer
    {
        // Properties
        #region IDataItemContainer Members
        public object DataItem { get; internal set; }
        public int DataItemIndex { get; internal set; }
        public int DisplayIndex { get; internal set; }
        #endregion
    }
    #endregion
}
</code>