how export Array of a complex class to Excel using Interop

Question

private void btnDoctor_Click(object sender, EventArgs e)
{
Clear();
EmployeeWebservice.EmployeeData [] hm;
hm = hc.GetAllDoctors(lg);
dataGridView1.DataSource = hm;
SSiNETProjectLibrary.Utils.DataGridViewExport.exportToExcel(dataGridView1);
MessageBox.Show("Doctors Details Exported", "", MessageBoxButtons.OK, MessageBoxIcon.Information);
lblmsg.Text = "";
}

The above one iam tried, it is working.. but i can not customize because of the use of a external dll.

 

anybody can give the source using interop?