Excel.Range selectedRange = (Excel.Range)objApp.Selection;
        selectedRange.Columns.AutoFit();
        selectedRange.HorizontalAlignment = HorizontalAlignment.Center;

In the above code, AutoFit works, but Horizontal Alignment doesn't.

  Excel.Range TitleRange = (Excel.Range)xlWorkSheet.get_Range("A3", "M3");
      TitleRange.Style.HorizontalAlignment = HorizontalAlignment.Center;

I tried this..it doesn't work either

I want to enter the text in cells A3-M3.
Any ideas?