How to Get max value from IEnumerable

Question

IEnumerable<DataGridViewRow> l_selectedRowobj = this.dataGridView1.SelectedRows.Cast<DataGridViewRow>().OrderBy(abc => abc.Index);
l_selectedRowobj.Max();

l_selectedRowobj.Max(); I get a NULL value at this line

I dont want to use List for getting max count like below:

List<int> listofRowIndex = new List<int>();
foreach (DataGridViewRow row in l_selectedRowobj)
{
    listofRowIndex.Add(row.Index);
} 
int maxrowind = listofRowIndex.Max();

Answer 1

You need to check if the sequence contains any elements first - if it does, then you can get Max value from that sequence by given property:

if (l_selectedRowobj.Any())
{
     int max = l_selectedRowobj.Max(row => row.Index);
}

or this if you want to assign some value to max in case the sequence is empty:

int max = l_selectedRowobj.Any() ? l_selectedRowobj.Max(row => row.Index) : 0; 

Answer 2

You should give your .Max() method a clue which property it should use to compare against the others and find the biggest one:

int max = l_selectedRowobj.Max(row => row.Index);