C# how can add bulk items to datagridview from richtextbox and save as excel file?

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C#

Hi I have 2 datagridview, 1 richtextbox and 2 button

I want to do when I click the button1 create a table on datagridview1 and add the bulk datas from richtextbox to datagridview1 column

for example

No | Product Name
1    Apple
2    Banana
3    Pear
4    Orange....
..   ...

and when I click the button2 save as .xlsx file and list on datagridview2

What I can't make is adding bulk item to datagridview column from richtextbox all other I can do

what I'm asking how can I make this?

What I have tried:

using System.Data.OleDb;

        OleDbConnection odc = new OleDbConnection
            (@"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\Users\Yusuf\Desktop\x\bilgiler.xlsx;Extended Properties='Excel 12.0 Xml; HDR=YES;IMEX=1;'");

        void veriler()
        {
            OleDbDataAdapter da = new OleDbDataAdapter("Select * From [bilgiler$]", odc);
            DataTable dt1 = new DataTable();
            da.Fill(dt1);
            dataGridView2.DataSource = dt1;
        }

private void button2_Click(object sender, EventArgs e)
{
    odc.Open();
    OleDbCommand cmd = new OleDbCommand("insert into [bilgiler$] (Products) values (@p1)",odc);
    cmd.Parameters.AddWithValue("@p1",richTextBox1.Text);
    cmd.ExecuteNonQuery();
    odc.Close();
    veriler();
}