Rotate text only in specific Excel row

Question

I'd like to rotate headers in an Excel file using Microsoft.Office.Interop. To achieve this, I'm using the following code:

worksheet.Range["A1:" + worksheet.UsedRange.Columns.Count + "1"].Style.Orientation
    = Excel.XlOrientation.xlUpwards;

The result looks like this:

As you can see, every cell gets rotated although I'm only specifying the first row. However, I just want the headers to be rotated:

I even tried it with a for loop for every column:

for (int counter = 1; counter <= worksheet.UsedRange.Columns.Count; counter++)
    worksheet.Range[GetExcelColumnName(counter) + "1"].Style.Orientation
        = Excel.XlOrientation.xlUpwards;

But I get the same result. What should I do to only change the orientation of the headers?

(Method GetExcelColumnName)

Answer 1

Just convert the entire row 1.

worksheet.Range["1:1"].Style.Orientation = Excel.XlOrientation.xlUpwards;
worksheet.Rows["1"].Style.Orientation = Excel.XlOrientation.xlUpwards;

fwiw, in VBA this might be best handled with application.intersect of rows(1) and the .usedrange. From your code it looks like that would be,

Excel.Intersect(worksheet.Range["1:1"], worksheet.UsedRange).Style.Orientation = Excel.XlOrientation.xlUpwards;
/* just the cells, not the style */
Excel.Intersect(worksheet.Range["1:1"], worksheet.UsedRange).Cells.Orientation = Excel.XlOrientation.xlUpwards;