Closing Excel Application Process in C# after Data

Question

I'm writing an application in C# that opens an Excel template file for read/write operations. I want to when user closes the application, excel application process has been closed, without saving excel file. See my Task Manager after multiple runs of the app.

I use this code to open the excel file :

public Excel.Application excelApp = new Excel.Application();
public Excel.Workbook excelBook;
excelBook = excelApp.Workbooks.Add(@"C:/pape.xltx");

and for data access I use this code :

Excel.Worksheet excelSheet = (Worksheet)(excelBook.Worksheets[1]);
excelSheet.DisplayRightToLeft = true;
Range rng;
rng = excelSheet.get_Range("C2");
rng.Value2 = txtName.Text;

I see similar questions in stackoverflow such as this question and this, and test answers, but it doesn't works.

Answer 1

Ref: https://stackoverflow.com/a/17367570/132599

Avoid using double-dot-calling expressions, such as this:

var workbook = excel.Workbooks.Open(/*params*/)

...because in this way you create RCW objects not only for workbook, but for Workbooks, and you should release it too (which is not possible if a reference to the object is not maintained).

This resolved the issue for me. Your code becomes:

public Excel.Application excelApp = new Excel.Application();
public Excel.Workbooks workbooks;
public Excel.Workbook excelBook;
workbooks = excelApp.Workbooks;
excelBook = workbooks.Add(@"C:/pape.xltx");

...

Excel.Sheets sheets = excelBook.Worksheets;
Excel.Worksheet excelSheet = (Worksheet)(sheets[1]);
excelSheet.DisplayRightToLeft = true;
Range rng;
rng = excelSheet.get_Range("C2");
rng.Value2 = txtName.Text;

And then release all those objects:

System.Runtime.InteropServices.Marshal.ReleaseComObject(rng);
System.Runtime.InteropServices.Marshal.ReleaseComObject(excelSheet);
System.Runtime.InteropServices.Marshal.ReleaseComObject(sheets);
excelBook .Save();
excelBook .Close(true);
System.Runtime.InteropServices.Marshal.ReleaseComObject(xlBook);
System.Runtime.InteropServices.Marshal.ReleaseComObject(workbooks);
excelApp.Quit();
System.Runtime.InteropServices.Marshal.ReleaseComObject(xlApp);

I wrap this in a try {} finally {} to ensure everything gets released even if something goes wrong (what could possibly go wrong?) e.g.

public Excel.Application excelApp = null;
public Excel.Workbooks workbooks = null;
...
try
{
    excelApp = new Excel.Application();
    workbooks = excelApp.Workbooks;
    ...
}
finally
{
    ...
    if (workbooks != null) System.Runtime.InteropServices.Marshal.ReleaseComObject(workbooks);
    excelApp.Quit();
    System.Runtime.InteropServices.Marshal.ReleaseComObject(xlApp);
}

Answer 2

Think of this, it kills the process:

System.Diagnostics.Process[] process=System.Diagnostics.Process.GetProcessesByName("Excel");
foreach (System.Diagnostics.Process p in process)
{
    if (!string.IsNullOrEmpty(p.ProcessName))
    {
        try
        {
            p.Kill();
        }
        catch { }
    }
}

Also, did you try just close it normally?

myWorkbook.SaveAs(@"C:/pape.xltx", missing, missing, missing, missing, missing, Microsoft.Office.Interop.Excel.XlSaveAsAccessMode.xlNoChange, missing, missing, missing, missing, missing);
excelBook.Close(null, null, null);                 // close your workbook
excelApp.Quit();                                   // exit excel application
excel = null;                                      // set to NULL

Answer 3

Use a variable for each Excel object and must loop Marshal.ReleaseComObject >0. Without the loop, Excel process still remain active.

public class test{
        private dynamic ExcelObject;
        protected dynamic ExcelBook;
        protected dynamic ExcelBooks;
        protected dynamic ExcelSheet;

public void LoadExcel(string FileName)
        {
            Type t = Type.GetTypeFromProgID("Excel.Application");
            if (t == null) throw new Exception("Excel non installato");
            ExcelObject = System.Activator.CreateInstance(t);
            ExcelObject.Visible = false;
            ExcelObject.DisplayAlerts = false;
            ExcelObject.AskToUpdateLinks = false;
            ExcelBooks = ExcelObject.Workbooks;
            ExcelBook = ExcelBooks.Open(FileName,0,true);
            System.Runtime.InteropServices.Marshal.GetActiveObject("Excel.Application");
            ExcelSheet = ExcelBook.Sheets[1];
        }
 private void ReleaseObj(object obj)
        {
            try
            {
                int i = 0;
             while(   System.Runtime.InteropServices.Marshal.ReleaseComObject(obj) > 0)
                {
                    i++;
                    if (i > 1000) break;
                }
                obj = null;
            }
            catch 
            {
                obj = null;
            }
            finally
            {
                GC.Collect();
            }
        }
        public void ChiudiExcel() {
            System.Threading.Thread.CurrentThread.CurrentCulture = ci;

            ReleaseObj(ExcelSheet);
            try { ExcelBook.Close(); } catch { }
            try { ExcelBooks.Close(); } catch { }
            ReleaseObj(ExcelBooks);
            try { ExcelObject.Quit(); } catch { }
            ReleaseObj(ExcelObject);
        }
}

Answer 4

Based on another solutions. I have use this:

IntPtr xAsIntPtr = new IntPtr(excelObj.Application.Hwnd);
excelObj.ActiveWorkbook.Close();

System.Diagnostics.Process[] process = System.Diagnostics.Process.GetProcessesByName("Excel");
                foreach (System.Diagnostics.Process p in process)
                {
                    if (p.MainWindowHandle == xAsIntPtr)
                    {
                        try
                        {
                            p.Kill();
                        }
                        catch { }
                    }
                }

Using the "MainWindowHandle" to identify the process and close him.

excelObj: This is my Application Interop excel objecto

Answer 5

I met the same problems and tried many methods to solve it but doesn't work. Finally , I found the by my way. Some reference enter link description here

Hope my code can help someone future. I have been spent more than two days to solve it. Below is my Code:

//get current in useing excel
            Process[] excelProcsOld = Process.GetProcessesByName("EXCEL");
            Excel.Application myExcelApp = null;
            Excel.Workbooks excelWorkbookTemplate = null;
            Excel.Workbook excelWorkbook = null;
try{
    //DO sth using myExcelApp , excelWorkbookTemplate, excelWorkbook
}
catch (Exception ex ){
}
finally
            {
                //Compare the EXCEL ID and Kill it 
                Process[] excelProcsNew = Process.GetProcessesByName("EXCEL");
                foreach (Process procNew in excelProcsNew)
                {
                    int exist = 0;
                    foreach (Process procOld in excelProcsOld)
                    {
                        if (procNew.Id == procOld.Id)
                        {
                            exist++;
                        }
                    }
                    if (exist == 0)
                    {
                        procNew.Kill();
                    }        
                }
            }

Answer 6

Most of the methods works, but the excel process always stay until close the appliation.

When kill excel process once it can't be executed once again in the same thread - don't know why.