private IQueryable <dynamic> Sort(IQueryable <dynamic> data, SortInfo sortInfo)
{
if (!String.IsNullOrEmpty(sortInfo.SortColumn) || ((DefaultSort != null) && !String.IsNullOrEmpty(DefaultSort.SortColumn)))
{
return(Sort(data, _elementType, sortInfo));
}
return(data);
}
public IList <GenericWebGridRow> GetRows(SortInfo sortInfo, int pageIndex)
{
IEnumerable <dynamic> rowData = _values;
if (_canSort)
{
rowData = Sort(_values.AsQueryable(), sortInfo);
}
rowData = Page(rowData, pageIndex);
try {
// Force compile the underlying IQueryable
rowData = rowData.ToList();
}
catch (ArgumentException) {
// The OrderBy method uses a generic comparer which fails when the collection contains 2 or more
// items that cannot be compared (e.g. DBNulls, mixed types such as strings and ints et al) with the exception
// System.ArgumentException: At least one object must implement IComparable.
// Silently fail if this exception occurs and declare that the two items are equivalent
rowData = Page(_values.AsQueryable(), pageIndex);
}
return(rowData.Select((value, index) => new GenericWebGridRow(_grid, value: value, rowIndex: index)).ToList());
}
public IList <GenericWebGridRow> GetRows(SortInfo sortInfo, int pageIndex)
{
// Data is already sorted and paged. Ignore parameters.
return(_rows);
}
private IQueryable <dynamic> Sort(IQueryable <dynamic> data, Type elementType, SortInfo sort)
{
Debug.Assert(data != null);
if (typeof(IDynamicMetaObjectProvider).IsAssignableFrom(elementType))
{
// IDynamicMetaObjectProvider properties are only available through a runtime binder, so we
// must build a custom LINQ expression for getting the dynamic property value.
// Lambda: o => o.Property (where Property is obtained by runtime binder)
// NOTE: lambda must not use internals otherwise this will fail in partial trust when Helpers assembly is in GAC
var binder = Binder.GetMember(
CSharpBinderFlags.None,
sort.SortColumn,
typeof(WebGrid),
new[] { CSharpArgumentInfo.Create(CSharpArgumentInfoFlags.None, null) }
);
var param = Expression.Parameter(typeof(IDynamicMetaObjectProvider), "o");
var getter = Expression.Dynamic(binder, typeof(object), param);
return(SortGenericExpression <IDynamicMetaObjectProvider, object>(
data,
getter,
param,
sort.SortDirection
));
}
Expression sorterFunctionBody;
ParameterExpression sorterFunctionParameter;
Expression sorter;
if (_grid.CustomSorters.TryGetValue(sort.SortColumn, out sorter))
{
var lambda = sorter as LambdaExpression;
Debug.Assert(lambda != null);
sorterFunctionBody = lambda.Body;
sorterFunctionParameter = lambda.Parameters[0];
}
else
{
// The IQueryable<dynamic> data source is cast as IQueryable<object> at runtime. We must call
// SortGenericExpression using reflection so that the LINQ expressions use the actual element type.
// Lambda: o => o.Property[.NavigationProperty,etc]
sorterFunctionParameter = Expression.Parameter(elementType, "o");
Expression member = sorterFunctionParameter;
var type = elementType;
var sorts = sort.SortColumn.Split('.');
foreach (var name in sorts)
{
PropertyInfo prop = type.GetProperty(name);
if (prop == null)
{
// no-op in case navigation property came from querystring (falls back to default sort)
if (
(DefaultSort != null) &&
!sort.Equals(DefaultSort) &&
!String.IsNullOrEmpty(DefaultSort.SortColumn)
)
{
return(Sort(data, elementType, DefaultSort));
}
return(data);
}
member = Expression.Property(member, prop);
type = prop.PropertyType;
}
sorterFunctionBody = member;
}
var actualSortMethod = SortGenericExpressionMethod.MakeGenericMethod(
elementType,
sorterFunctionBody.Type
);
return((IQueryable <dynamic>)actualSortMethod.Invoke(
null,
new object[]
{
data,
sorterFunctionBody,
sorterFunctionParameter,
sort.SortDirection
}
));
}
