I am new to Microsoft.Office.Interop.Excel Marshal.ReleaseComObject

Hello,

Here is a very simple example that opens an Excel file, gets all sheet names, writes data to a cell, saves the file and finally releases all objects. Again this is a simple example to keep things easy to understand.

/// <summary>
/// The code accepts an Excel file to open, iterates thru the
/// WorkSheets collection checking the name passed in parameter 2
/// to see if it matches and if so sets a boolean so after the for-next
/// we can know if the sheet is there and safe to work on.
/// </summary>
/// <param name="FileName"></param>
/// <param name="SheetName"></param>
public void OpenExcel(string FileName, string SheetName)
{
    List<string> SheetNames = new List<string>();

    bool Proceed = false;
    Excel.Application xlApp = null;
    Excel.Workbooks xlWorkBooks = null;
    Excel.Workbook xlWorkBook = null;
    Excel.Worksheet xlWorkSheet = null;
    Excel.Sheets xlWorkSheets = null;

    xlApp = new Excel.Application();
    xlApp.DisplayAlerts = false;
    xlWorkBooks = xlApp.Workbooks;
    xlWorkBook = xlWorkBooks.Open(FileName);

    xlApp.Visible = false;
    xlWorkSheets = xlWorkBook.Sheets;

    for (int x = 1; x <= xlWorkSheets.Count; x++)
    {
        xlWorkSheet = (Excel.Worksheet)xlWorkSheets[x];

        SheetNames.Add(xlWorkSheet.Name);

        if (xlWorkSheet.Name == SheetName)
        {
            Proceed = true;
            Excel.Range xlRange1 = null;
            xlRange1 = xlWorkSheet.Range["A1"];
            xlRange1.Value = "Hello";
            Marshal.FinalReleaseComObject(xlRange1);
            xlRange1 = null;
            xlWorkSheet.SaveAs(FileName);
            break;
        }

        System.Runtime.InteropServices.Marshal.FinalReleaseComObject(xlWorkSheet);
        xlWorkSheet = null;
    }

    xlWorkBook.Close();
    xlApp.Quit();

    ReleaseComObject(xlWorkSheets);
    ReleaseComObject(xlWorkSheet);
    ReleaseComObject(xlWorkBook);
    ReleaseComObject(xlWorkBooks);
    ReleaseComObject(xlApp);

    if (Proceed)
    {
        MessageBox.Show("Found sheet, do your work here.");
    }
    else
    {
        MessageBox.Show("Sheet not located");
    }

    MessageBox.Show("Sheets available \n" + String.Join("\n", SheetNames.ToArray()));
}

private void ReleaseComObject(object obj)
{
    try
    {
        System.Runtime.InteropServices.Marshal.ReleaseComObject(obj);
        obj = null;
    }
    catch (Exception ex)
    {
        obj = null;
    }
}

One last thing, see the Two Dot Rule.

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