c# - datagrid view select row is not working -

i filled gridview cell cell without using datasource. when reload 1 column after drag , drop rows, not working:

row[6].selected = true; 

and turns color of row blue selected thing, when call if row selected returns me null! , that's because of sign in default column in gridview pointer each row. , when click on row selecting row manually shows again.

so my question how enable sign selecting process.

the datagridview can have multiple selected rows, if multiselect option set true.

the black arrow represents row has current cell selected.

so need set

this.datagridview1.currentcell = this.datagridview1.rows[1].cells[0]; 

for row , cell want highlighted black arrow.

also aware cell use must visible, enabled , not header cell otherwise might not work.