Database data show in combobox C#

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C

C#

I try this Code But Data Not Show

What I have tried:

private void fillCombo()
{
String connstring = ConfigurationManager.ConnectionStrings["FincorpData"].ConnectionString;
using (OleDbConnection con = new OleDbConnection(connstring))
{
using (OleDbDataAdapter oda = new OleDbDataAdapter("select DealerName form Dealer", con))
{
DataTable dt = new DataTable();
oda.Fill(dt);
comboBox1.DataSource = dt;
comboBox1.DisplayMember = "DealerName";

}
}
}