برای باز کردن فایل Word می تونی از این کد استفاده کنی :
قبلش Microsoft.Office.Interop.Word رو به Reference هات اضافه کن
OpenFileDialog Ofd = new OpenFileDialog();
Ofd.Filter = "Doc File|*.doc|Docx File|*.docx";
Ofd.CheckFileExists = true;
Ofd.CheckPathExists = true;
Ofd.InitialDirectory = @"C:\";
Ofd.RestoreDirectory = true;
if (Ofd.ShowDialog() == DialogResult.OK)
{
try
{
ApplicationClass Word = new ApplicationClass();
object file = Ofd.FileName;
object nullobject = System.Reflection.Missing.Value;
Document docs = Word.Documents.Open
(ref file, ref nullobject, ref nullobject, ref nullobject,
ref nullobject, ref nullobject, ref nullobject, ref nullobject,
ref nullobject, ref nullobject, ref nullobject, ref nullobject,
ref nullobject, ref nullobject, ref nullobject, ref nullobject
);
docs.ActiveWindow.Selection.WholeStory();
docs.ActiveWindow.Selection.Copy();
IDataObject data = Clipboard.GetDataObject();
richTextBox1.Text = data.GetData(DataFormats.Text).ToString();
docs.Close(ref nullobject, ref nullobject, ref nullobject);
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}