Filter complex objects in DataTable/DataView

Question

I want to filter a DataTable or DaatView that contains complex objects.

Let's say I have this object Person

public class Person{      

public int Id{get; set;}     
public int Age{get; set;}     
public strng Name{get; set;}     
public Address BillAddress{get; set;} 
}  

public class Address{          
public string 
Town{get; set}    
public string Street{get; set}     
public int Number{get; set} 
}

Now i fill a DataView with a list of Person objects:

  public static DataView ToObjectDataView<T>(this IList<T> list, int countOfColumns)
  {
     if (list == null || countOfColumns < 1)
     {
        return null;
     }
     int columns = countOfColumns;

     DataTable dataTable = new DataTable();

     for (int currentCol = 0; currentCol != columns; currentCol++)
     {
        DataColumn column = new DataColumn(currentCol.ToString(), typeof(T));
        dataTable.Columns.Add(column);
     }

     DataRow row = null;
     int currentColumn = 0;
     for (int index = 0; index < list.Count; index++)
     {
        if (list[index] == null)
        {
           continue;
        }
        if (Equals(null, row))
           row = dataTable.NewRow();

        row[currentColumn] = list[index];
        currentColumn++;

        if (currentColumn == columns)
        {
           dataTable.Rows.Add(row);
           row = null;
           currentColumn = 0;
        }
     }

     //Verarbeitung der letzten Zeile
     if (!Equals(null, row))
     {
        dataTable.Rows.Add(row);
     }

     return new DataView(dataTable);
  }

So that i get a DataView with 10 columns of Person objects, evrey column has the name of its index:

IList<Person> personList = new List<Person>();
// Fill the list...
DataView dataSource = personList.ToObjectDataSource(10);

Now I would like to filter this DataView based on child values with an expression, for example, get all persons that live in the 'Fakestreet'.

I tried "0.BillAddress.Street = 'Fakestreet'"(and or expression with the rest columns) but that doesn't work..

Franki1986 Franki1986 · Accepted Answer · 2016-05-25T14:33:44

This is a partial solution, because I didn't find a direct way.

Use the DataTable AsEnumerable extension and filter with dynamic linq (System.Linq.Dynamic (also available for .Net 3.5))

  // Filter directly the List
  public static List<T> FilterByLinqExpression<T>(this IList<T> list, string linqFilterExpression)
  {
     var result = list.AsQueryable().Where(linqFilterExpression);
     return result.ToList<T>();
  }

So you can call it like this for all persons that live in a street that has 'Avenue' in it's name:

IList<Person> personList = new List<Person>();
// Fill the list...
var filteredValues = personList.FilterByLinqExpression("((BillAddress.Street).Contains(\"Avenue\"))");
DataView dataSource = filteredValues .ToObjectDataSource(10);

I use this to filter for example complex objects that are used to be displayed in a DevExpress ASPxGridView. By the way, they have an automatic converter from their filter expressions to different filter expression, in my case the 'CriteriaToWhereClauseHelper.GetDynamicLinqWhere()' that converts the given filter expression to a dynamic linq expression.

Filter complex objects in DataTable/DataView

1 Answers