Try it like this:
PrinterSettings ps = new PrinterSettings();
PrinterData pd = new PrinterData();
PrintDocument printDoc = new PrintDocument();
PaperSource pkSource;
ArrayList arr = new ArrayList();
private void Form1_Load(object sender, EventArgs)
{
for (int i = 0; i < printDoc.PrinterSettings.PaperSources.Count; i++)
{
if (printDoc.PrinterSettings.PaperSources[i].SourceName == "Frontoffice")
{
pkSource = printDoc.PrinterSettings.PaperSources[i];
}
arr.Add(printDoc.PrinterSettings.PaperSources[i]);
}
comboPaperSource.DataSource = arr;
comboPaperSource.DisplayMember = "SourceName";
comboPaperSource.ValueMember = "RawKind";
comboPaperSource.SelectedItem = pkSource;
}