Have your users make spreadsheets online, no excel needed

Now first off, this places a DataTable intot he Session State, and I know some people have a problem with that... I don't care.  Now that that is out of the way, I can explain how this works.

It is very simple, this program runs through all of the TextBoxes and DropDownLists that you have within the input_container Panel and adds them as string columns to a DataTable dt.  Once that is done, each entry is simply added to the DataTable and rendered onto a GridView.  Then I use Matt Berseth's GridViewExportUtil to spit the spreadsheet out to the user.  Everything is taken care of real-time with no writing to the disk. Pretty simple.

I also included a way to edit as a normal method wouldn't work in this case, it just populates a DropDownList every time you add a new item and pops it back into the forms if you choose to edit it _but_ if you do not save, the record will be lost (there is a warning).

Another thing to note is that this is a drop-in-and-use application.  Everything is populated automatically, you need to do absolutely nothing to the code-behind in order to use this utility, just customize your fields in the default.aspx in the input_container and the rest of the work is done for you.  I used my method of parsing IDs of the input fields to make column names so ddlLets_Party turns in to a column "Lets Party", Last_Name becomes "Last Name", strFruit becomes "Fruit" and so on.   You could easily add another attribute as ColumnName or something like that if you please.

Here is the provided example: Excel Spreadsheet Builder In Action, and the code:

This can be done via a web-interface via Excel Interop commands

I was asked to take some user input, produce an Excel spreadsheet, then append it to an exisiting workbook that had multiple static spreadsheets then spit the Excel sheet out as a download.  Excel Interop processes are not that easy to work with, and can be quite a pain.  After fumbling around, I was able to come up with a (possibly rudimentary) way to do this.

Now this is just a small part of a much larger program that takes in user input, and saves it to a temporary directory as an Excel spreadsheet.  Inside that directory there is also another file that doesn't change that thsi will be appended to, I call this my 'base' file.  The snippet I am providing combines the files and saves them as a seperate new file before my program sends it to the user.

There is likely a better way to do this without all of the saving with a stream, but I am not sure how and am wide open for better solutions!  Anyways, here is the function I ended up using.  The inputs are:

• baseFile is the path to the static file I am appending to
• newSheet is the path to the new file that I am appending to the base
• newFile is the path to the final appended sheet 

If you have ever worked with Excel in the .Net environment, you likely have run across the occasional orphan and they can be a pain to clean up

Recently I was doing just this, and my Task Manager was filling up with orphans fast.  I was calling for the Excel Process to close, but that wasn't working most of the time.  So I came up with a more elaborate way to make them disappear.  Basically I found out that in order to close the application, you have to close the workbooks, and in order to close the workbooks, you have to close each workbook individually, and to close those, you have to close each worksheet in those workbooks individually.  I also included COM management, so we are hitting this with multiple attacks to make sure they stay dead!  So the super-overkill-do-everything process is:

1. Collect each worksheet individually
2. Collect each workbook individually
3. Delete the worksheets
4. Release the worksheets
5. Null the worksheets
   
6. Delete the workbooks
7. Release the workbooks
8. Null the workbooks
9. Close the workbooks collection
10. Quit the application
11. Release the application
12. Null the application
13. Collect garbage

Here's how

After your work is done, you are left with a Microsoft.Office.Interop.Excel.Application named 'exc', call killExcel(exc):

protected void killExcel(Microsoft.Office.Interop.Excel.Application exc)
{
    try
    {
        List<Microsoft.Office.Interop.Excel.Workbook> wbs = new List<Microsoft.Office.Interop.Excel.Workbook>();
        List<Microsoft.Office.Interop.Excel.Worksheet> wss = new List<Microsoft.Office.Interop.Excel.Worksheet>();
        foreach (Microsoft.Office.Interop.Excel.Workbook wb in exc.Workbooks)
        {
            foreach (Microsoft.Office.Interop.Excel.Worksheet ws in wb.Worksheets)
                wss.Add(ws); // collect worksheets
            wbs.Add(wb); // collect workbooks
        }
        for (int i = 0; i < wss.Count; i++)
        {
            wss[i].Delete();
            System.Runtime.InteropServices.Marshal.ReleaseComObject(wss[i]); // release it
            wss[i] = null; // null it
        }
        for (int i = 0; i < wbs.Count; i++)
        {
            wbs[i].Close(null, null, null);
            System.Runtime.InteropServices.Marshal.ReleaseComObject(wbs[i]); // release it
            wbs[i] = null; // null it
        }
        exc.Workbooks.Close(); // so you can close this
        exc.Quit(); // so you can quit this
        System.Runtime.InteropServices.Marshal.ReleaseComObject(exc); // release it
        exc = null;
        GC.Collect(); // this sets up the finalizers
        GC.WaitForPendingFinalizers();
        GC.Collect(); //apparently this kills it
        GC.WaitForPendingFinalizers();
    }
    catch (Exception ex)
    {
        // deal with it fool!
    }
}

Yes this is overkill, but I think I covered all possible ways to kill you processes, so they should be more dead than Elvis; no more orphans - yay for iteration!

Some useful links:

http://www.thescarms.com/dotnet/ExcelObject.aspx 

http://www.devcity.net/Articles/239/3/article.aspx 

http://krgreenlee.blogspot.com/...ting-excel_10.html 

Matt Berseth supplies an awesome way to export to excel with pretty much no hassle whatsoever

Just add in his class and call it withing as event like this 

GridViewExportUtil.Export("save_as_this.xls", this.GridViewName);

A way to easily manipulate data from an excel spreadsheet programmatically

I work in an office environment which is dominated by Microsoft Excel spreadsheets, and so often, people want to use them in programs.  I am a SQL junky myself, but Excel is appropriate in a lot of cases, but integrating them into programs can be a pain.  More specifically, getting the data from the Excel worksheet to a form where it is workable can be a pain. 

With this example, you can see how to take in an Excel Spreadsheet to get the data into commonly manipulatable data types in c#; then you can use/change it however you want to.  This demo shows first how to put the data into a dataset, then datatable (almost the same thing), then takes the same data in puts it into a multi-dimensional array (I prefer to work it arrays).  Since this is a linear progression, the demo only outputs the information from the array into an html table to show that it worked. 

The demo uses the very first row as teh column names (as it is used in datatable) and assumes that the Spreadsheet is in default format with Sheet1 as it's first sheet.  The demo only processes Sheet1.  This can be easily customized if you want to process more. 

With this, you can take/change/display the excel data however you want to using asp.net controls like ListView or GridView or just simple c#.  The code is pretty well commented, so you should be able to pull the parts that you may need.  *NOTE: you need full trust enabled for this to work properly.