How to get datagridcell from datagrid

Not sure what your trying to say, but if you mean how do I unselect a selected cell...

for a single cell:

// Cell, DataGridView[columnindex, rowindex]
MyGrid[0, 0].Selected = false;

for all selected cells:

if(MyGrid.SelectedCells.Count != 0)
     for(int i = 0; i < MyGrid.SelectedCells.Count; i++){
          MyGrid.SelectedCells[i].Selected = false;
     }

you may need to call invaliate on the DataGridView to reflect the changes.

//Invalidate, DataGridView to redraw its surface.
MyGrid.Invalidate();