Search value with datatable select in specific row range

You can try something like below. But be aware that the outcome could be different depending on the way the data being sorted in the datatable. Or you can make the datasource to return row_number as suggested by other member and then filter by that variable.

void Test()
{
    DataTable table = new DataTable();
    table.Columns.Add("Dosage", typeof(int));
    table.Columns.Add("Drug", typeof(string));
    table.Columns.Add("Patient", typeof(string));
    table.Columns.Add("Date", typeof(DateTime));

    // Here we add five DataRows.
    table.Rows.Add(25, "Indocin", "David", DateTime.Now);
    table.Rows.Add(50, "Enebrel", "Sam", DateTime.Now);

    table.Rows.Add(10, "Hydralazine", "Christoff", DateTime.Now);
    table.Rows.Add(21, "Combivent", "Janet", DateTime.Now);
    table.Rows.Add(100, "Dilantin", "Melanie", DateTime.Now);
    table.Rows.Add(22, "xx", "dd", DateTime.Now);

    table.Rows.Add(777, "Dilantin 2", "cc", DateTime.Now);

    //this should return 10,21,100,22
    var resultRange = table.AsEnumerable()
                      .Where((row, index) => index >= 2 && 5 >= index)
                      .CopyToDataTable();

    //this should return 100
    var value = "di";
    var result = resultRange.Select("Drug like '%" + value + "%'");
}

c# - How to select rows from DataTable based on Index / Row Number? - Stack Overflow[^]

https://www.dotnetperls.com/datatable[^]