How to display a new row without removing the previous rows (c# datagridview)?

nvm got it to work wee thanks kiran.

now I want to add some more functionality. this time I want to make so that if I input a cardnum thats already being displayed. it removes the row from the datagridview (not the database, just in the datagridview) heres what I got so far


private void CheckKeys3(object sender, System.Windows.Forms.KeyPressEventArgs e)
{
if (e.KeyChar == (char)13)
{
string card = textBox1.Text.ToString();
int cardnum = int.Parse(card);
park = park - 1;
OleDbConnection con = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=car.mdb");
con.Open();

OleDbCommand queryString = new OleDbCommand("SELECT cardnum, ownerf, ownerl, make, model, year, color, chassisnumber, platenumber, controlnumber FROM vehicle WHERE vehicle.cardnum = " + cardnum + "",con);
OleDbDataReader dr = queryString.ExecuteReader();
if (dr.Read())
{
DataGridViewRow row = new DataGridViewRow();
this.dataGridView1.Rows.Add(row);
dataGridView1.Rows[i].Cells[0].Value = dr["cardnum"].ToString();
dataGridView1.Rows[i].Cells[1].Value = dr["ownerf"].ToString();
dataGridView1.Rows[i].Cells[2].Value = dr["ownerl"].ToString();
dataGridView1.Rows[i].Cells[3].Value = dr["make"].ToString();
dataGridView1.Rows[i].Cells[4].Value = dr["model"].ToString();
dataGridView1.Rows[i].Cells[5].Value = dr["year"].ToString();
dataGridView1.Rows[i].Cells[6].Value = dr["color"].ToString();
dataGridView1.Rows[i].Cells[7].Value = dr["chassisnumber"].ToString();
dataGridView1.Rows[i].Cells[8].Value = dr["platenumber"].ToString();
dataGridView1.Rows[i].Cells[9].Value = dr["controlnumber"].ToString();

int k=i;
do
{
k = k - 1;
if (k >=0)
{
string wah =  dataGridView1[0, k].Value.ToString();
int weh = int.Parse(wah);
if (cardnum == weh)
{
dataGridView1.Rows.RemoveAt(k);
dataGridView1.Rows.RemoveAt(i);
}
}
} while (k >=0);

i++;
}
con.Close();
}

the bold text is my attempt. but its messed up. any help pls

dunno if I fixed the previous error (or its still there) but now I get this error
"No row can be added to a DataGridView control that does not have columns. Columns must be added first."

its in form2. and can you explain what I did wrong after. thanks in advance

been grappling with this error

ExecuteReader: Connection property has not been initialized.

replace like this
Oledbconnection con = new Oledbconnection(your connection string);
replace all class related to sqlclient to oledb
if it is sqlcommand replace it with oledbcommand
if it is sqldatareader->oledbdatareader
sqldataadapter->oledbdataadapter
PLEASE MARK THE ANSWER IF IT HELPS YOU

havent tried it yet but I'll mark you anyway :) one question:

SqlConnection con = new SqlConnection("Data Source=KIRAN\\SQLEXPRESS;Initial Catalog=kiran;Integrated Security=True");

where do I instance my database. I've only used OleDb before so I dont know how to in your code.

no the data is already in the database, I dont want to store or update or anything. I just want to display the data on the datagridview.

private void CheckKeys3(object sender, System.Windows.Forms.KeyPressEventArgs e)
{
if (e.KeyChar == (char)13)
{
string card = textBox1.Text.ToString();
int cardnum = int.Parse(card);
park = park - 1;
string queryString = "SELECT cardnum, ownerf, ownerl, make, model, year, color, chassisnumber, platenumber, controlnumber FROM vehicle WHERE vehicle.cardnum = " + cardnum + "";
loadDataGrid(queryString);

if (park > 0)
{
textBox2.Text = "available";
}

if (park < 1)
{
textBox2.Text = "full";
}

textBox1.Clear();
}
}

thats for the query string, note since I am querying using the primary key. only 1 row of data will be displayed on the datagridview. what I want is to make it so that if I make another query the previous row of data will still be there along with the newly queried row of data. anyway to do this?