obtener los valores de la columna datagrid

Dim query1 = (From i As DataGridViewRow In dg_captura.Rows Select i.Cells(0)).ToList()


Busca elemento repetido en una columna especifica
Dim query2 = query1.GroupBy(Function(x) x.Value).Where(Function(g) g.Count > 1).Select(Function(y) y.Key).ToList()