Data view filter not working correctly

Question

I have the following code

DataView dv = new DataView(dsModels.Tables[0]);
string strFilter = "MODEL = 'PISTON'";
dv.RowFilter = strFilter;

string strPN = dv.Table.Rows[0]["PN"].ToString();

The dataview dv has a count of 35 rows prior to applying the filter. After I apply the filter the dv.count is 1

But when i set the strPN to the value of the filtered DV i am getting the first row pn value. if i set string so with a 15; i get the 15 row pn value even though DV has a count of 1 ????

How do i get the value of the filter row where Model= PISTON

Answer 1

Taken from dataview.rowfilter and dataview.count:

• RowFilter: Gets or sets the expression used to filter which rows are viewed in the DataView.
• Count: Gets the number of records in the DataView after RowFilter and RowStateFilter have been applied

The line dv.Table.Rows[0]["PN"].ToString(); is targeting the underlying datatable and not the current state of the dataview. You can copy the filtered rows using dv.ToTable()

This is a linqpad demo program. If you play around with it you will get the hang of it

void Main()
{

    DataView dataview = GetTable().DefaultView; 
    dataview.RowFilter = "Name = 'John'";
    DataTable dataTable = dataview.ToTable();
    // dataview.Dump();
    dataTable.Dump();
    var row0 = dataview.Table.Rows[0]; 
    var row1 = dataview.Table.Rows[1];
    string.Join("|",row0.ItemArray).Dump();
    string.Join("|",row1.ItemArray).Dump(); 
}

This is the helper method

static DataTable GetTable()
{
   // DataTable with 4 columns
   DataTable table = new DataTable("Students");
   table.Columns.Add("Id", typeof(int));
   table.Columns.Add("Name", typeof(string));
   table.Columns.Add("Teacher", typeof(string));
   table.Columns.Add("Birthday", typeof(DateTime));

   // Add 5 rows
   table.Rows.Add(1, "John", "Mr. Charles", DateTime.Parse("2001-01-01"));
   table.Rows.Add(2, "Lennard", "Mr. Charles", DateTime.Parse("2002-02-02"));
   table.Rows.Add(3, "John", "Lady Graham", DateTime.Parse("2003-03-03"));
   table.Rows.Add(4, "Penny", "Mr. Charles", DateTime.Parse("2004-04-04"));
   table.Rows.Add(5, "Sheldon", "Sir Winster", DateTime.Parse("2005-05-05"));
   return table;
}

You might also take a look at roslynpad