Unable to open another excel file (when one Excel is opened by .net)

Question

I have designed a .net application which will open an Excel file at the time of login and use it to print a report. It will be closed while logging out the user. I set visib

Answer 1

Looks like your problem is caused by the same instance of xlApp. What I would do is simple: I would initialize new instance of xlApp and then quite that instance of the application. This way it won't interfere with any other open instance of Excel. Here is how I use it in C#:

using Excel = Microsoft.Office.Interop.Excel;

Excel.Application xlApp = new Excel.Application();  // by default this is invisible

do whatever you have to do with the new instance of xlApp and then quite the application. Once you quite the application it won't be in your task manager.

xlApp.Application.Quit();

I have designed several applications where I had to process the same Excel files that most likely would've been open by those same users. This approach (opening new instance of excel in invisible mode and then quitting the application) never caused any problems for me.