C# and Excel Interop resource problem

see below

using Excel = Microsoft.Office.Interop.Excel;
...
 
Excel.Application xlApp = null;
Excel.Workbook xlWb = null;
Excel.Worksheet grid = null;
 
try {
xlApp = new Excel.ApplicationClass();
xlApp.Visible = false;
xlWb = xlApp.Workbooks.Open(fname, 0, false, 5, Missing.Value, Missing.Value, false, Missing.Value, Missing.Value, true, false, Missing.Value, false, false, false);
grid = (Excel.Worksheet)xlWb.Worksheets[<yourSheetName>];
...
do stuff
...
xlWb.Save();
}//end try
 
finally {
 
if (xlWb != null) { xlWb.Close(Missing.Value, Missing.Value, Missing.Value); }
 
if (xlApp != null) { xlApp.Quit(); }
}//end finally			
		

Select allOpen in new window

sorry, for Missing.Value you need to also include:

using System.Reflection;

What is pipelineWS in your code? and why do you switch from excelApp to app?

Hey rorya, sorry, that should be ws not pipelineWS.

I just changed the variable names when posting on here.

If you run the code with the Excel application visible are there any dialogs displayed at the end?

There are no dialog boxes displayed at the end.

I was doing some debugging and discovered that the resources are actually released, but not until the application is closed, or a garbage collection is forced and the method finishes.

I made a tiny app that simply opens then closes an excel workbook on a button click.

private void button1_Click(object sender, EventArgs e)
        {
            string masterSpreadsheet = "C:\\Data\\Master\\MasterRecommendation 2008.xls";

            Microsoft.Office.Interop.Excel.Application masterExcelApp = new Microsoft.Office.Interop.Excel.ApplicationClass();
            masterExcelApp.DisplayAlerts = false;
            masterExcelApp.Visible = true;
            masterExcelApp.EnableEvents = false;
            Microsoft.Office.Interop.Excel.Workbook masterWorkbook = masterExcelApp.Workbooks.Open(masterSpreadsheet, false, false, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing);
            Microsoft.Office.Interop.Excel.Worksheet masterws = (Microsoft.Office.Interop.Excel.Worksheet)masterExcelApp.ActiveSheet;

            masterWorkbook.Save();
            masterWorkbook.Close(true, System.Reflection.Missing.Value, System.Reflection.Missing.Value);
            masterExcelApp.Workbooks.Close();
            masterExcelApp.Quit();
            Marshal.ReleaseComObject(masterws);
            Marshal.ReleaseComObject(masterWorkbook);
            Marshal.ReleaseComObject(masterExcelApp);
        }

When I close the app the resources are released.

If I add a GC.Collect after the last line (Marshal.ReleaseComObject(masterExcelApp);)
then the resources are released after button_Click method is complete.

The problem is that I need the resources released before the method is complete because I am opening several sheets one after another in a loop. The resources have to be released right after the
Marshal.ReleaseComObject(masterExcelApp); line.

Anyone know how to force this?

Thanks a million rorya!!!

That works.