Dynamic linq for object collection - Target object is not an ExpandoObject

user_2747358 0
Viewed 926

I try to dynamically read the property values based on the text naming of these properties. This simply works for nested classes. But if there is a nested collection class, I would like to be able to select an item using a dynamic linq. Unfortunately, while reading in the collection, it returns

'Target object is not an ExpandoObject' (.FirstOrDefault).

Any idea to edit or possibly another solution?

My Code (.net core 2.1):

string value = string.Empty;

var dataClassProperty = dataClass.GetType().GetProperty(dataClassPropertyName).GetValue(dataClass, null);
if (dataClassProperty is IEnumerable<object>)
{
    object nestedPropertyItem = (dataClassProperty as IEnumerable<object>)
                                .AsQueryable()
                                .FirstOrDefault(collectionDynamicLinq);

    if (nestedPropertyItem != null)
        value = nestedPropertyItem.GetType().GetProperty(nestedPropertyName).GetValue(nestedPropertyItem, null)?.ToString() ?? "";
}
.net-core-2.1 dynamic-linq .net-core reflection c#
1 Answers

If you want to use Dynamic Linq on (database) entity classes, you could use System.Linq.Dynamic.Core.

With this you can easily write text based linq, like

var query = db.Customers
    .Where("City == @0 and Orders.Count >= @1", "London", 10)
    .OrderBy("CompanyName")
    .Select("new(CompanyName as Name, Phone)");
user_2559660
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