Question

I have a datatable in windows form and I want to add a new row to the table. I always receive the error

Table doesn’t have a primary key.

The question is that I don’t want a primary key at all. It may have duplicated “ID” in the table.
My code:

using (DataTable dt = new DataTable())
{
dt.Columns.Add("EntryDE", typeof(string));
dt.Columns.Add("Descr", typeof(string));
dt.Columns.Add("Id", typeof(int));
foreach (DataGridViewRow row in dgv.Rows)
{
    DataGridViewCheckBoxCell check = row.Cells[0] as DataGridViewCheckBoxCell;
    if (check.Value != null)
    {
        if ((bool)check.Value)
        {
            //this row has a checkBox set to true (tick is added)
            //add this row to dataTable ...
            DataRow myRow = (row.DataBoundItem as DataRowView).Row;
            DataRow dr = dt.NewRow();

            dr["EntryDE"] = myRow["ID"].ToString();        
            dr["Descr"] = myRow["EntryName"];               
            dr["Id"] = Id;    
                    dt.Rows.Add(dr);
        }
    }
}

Thanks for advice.

Answer 1

The error isn’t coming from the DataTable because this works:

    using (DataTable dt = new DataTable())
    {
        dt.Columns.Add("EntryDE", typeof(string));
        dt.Columns.Add("Descr", typeof(string));
        dt.Columns.Add("Id", typeof(int));

        for (int i = 0; i < 10; i++) 
        {
            DataRow dr = dt.NewRow();

            dr["EntryDE"] = "abc";
            dr["Descr"] = "xyz";
            dr["Id"] = 1;
            dt.Rows.Add(dr);
        }
    }

You’ve got some other problem.