For VerticalAlignment:
VerticalAlignment
Top: -4160Center: -4108Bottom: -4107
And HorizontalAlignment:
HorizontalAlignment
Left: -4131Center: -4108Right: -4152
You can use xlLeft:
Imports Microsoft.Office.Interop.Excel...oSheet.Range("A1").HorizontalAlignment = Constants.xlLeft
xcl.Range("J:J").EntireColumn.HorizontalAlignment = _Microsoft.Office.Interop.Excel.Constants.xlCenter