Checkbos in datagridview are not defalt 2. time I use the datadrid

Hi all

I'm working with a column of checkbox in datagridview. I can mark the cells
defalut false 1. time by set thristate to false and varpmode to false too =>
all the cell are default false befor I change by set the cells. So first time
I mark 4 cells and get its right but if I take one of the 4 cells and
iterelate again the unmark cells is nor false but null and I get a exeption.

// Search in DataGridView checkbox
foreach (DataGridViewRow row in this.dataGridView.Rows)
{

// compare Select checkbox and RMS database value and
RMS DataGridView column
if (((bool)row.Cells[0].Value) == true &&
row.Cells[1].Value.ToString().Trim() == originalTarget)
{ // Matck found
return true;
}
}// No match found
return false;



So its first time I sacn 2. time the default seting don't work

Best regart
Kim S.