I've tried to move away from direct COM interaction via Interop through third-party packages, but when that's not an option due to cost considerations, I'll use Office 2007/2010's built-in export functionality to accomplish this.
The method you need to call is Workbook.ExportAsFixedFormat()
Here is an example of how I use it an an export function:
public bool ExportWorkbookToPdf(string workbookPath, string outputPath)
{
// If either required string is null or empty, stop and bail out
if (string.IsNullOrEmpty(workbookPath) || string.IsNullOrEmpty(outputPath))
{
return false;
}
// Create COM Objects
Microsoft.Office.Interop.Excel.Application excelApplication;
Microsoft.Office.Interop.Excel.Workbook excelWorkbook;
// Create new instance of Excel
excelApplication = new Microsoft.Office.Interop.Excel.Application();
// Make the process invisible to the user
excelApplication.ScreenUpdating = false;
// Make the process silent
excelApplication.DisplayAlerts = false;
// Open the workbook that you wish to export to PDF
excelWorkbook = excelApplication.Workbooks.Open(workbookPath);
// If the workbook failed to open, stop, clean up, and bail out
if (excelWorkbook == null)
{
excelApplication.Quit();
excelApplication = null;
excelWorkbook = null;
return false;
}
var exportSuccessful = true;
try
{
// Call Excel's native export function (valid in Office 2007 and Office 2010, AFAIK)
excelWorkbook.ExportAsFixedFormat(Microsoft.Office.Interop.Excel.XlFixedFormatType.xlTypePDF, outputPath);
}
catch (System.Exception ex)
{
// Mark the export as failed for the return value...
exportSuccessful = false;
// Do something with any exceptions here, if you wish...
// MessageBox.Show...
}
finally
{
// Close the workbook, quit the Excel, and clean up regardless of the results...
excelWorkbook.Close();
excelApplication.Quit();
excelApplication = null;
excelWorkbook = null;
}
// You can use the following method to automatically open the PDF after export if you wish
// Make sure that the file actually exists first...
if (System.IO.File.Exists(outputPath))
{
System.Diagnostics.Process.Start(outputPath);
}
return exportSuccessful;
}