Review This Code:
DataTable dt = new DataTable();
dt.Columns.Add("A", typeof(Boolean));
dt.Columns.Add("B", typeof(string));
dt.Rows.Add(true,"A");
dt.Rows.Add(true, "B");
dt.Rows.Add(false, "C");
dt.Rows.Add(true, "D");
dt.Rows.Add(false, "E");
dgvMain.DataSource = dt;
DataGridViewRow[] drs = dgvMain.Rows.Cast<DataGridViewRow>().Where(x =>
(!Convert.IsDBNull(x.Cells[0].Value) && Convert.ToBoolean(x.Cells[0].Value)))
.ToArray();