folks,
Environment
Windows 8.1
Visual Studio 2013
C#
Issue
How do I write values and make charts on visible Excel sheets using NPOI (https://npoi.codeplex.com/).
Why do I want that?
I'm developing an application to measure temperature in an apparatus. To put together experimental data in one place, I'd like to record data on an Excel sheet and make a chart on the sheet. In addition, I'd like to keep the Excel sheet visible and check the chart updated in real time.
You could also make graphs on Windows Form apps with MeasurementStudio by NationalInstruments for example but considering the flexibility of Excel charts (size and xy range changeable, easy-to-use user interface, etc...), I'd like to stick to Excel.
You can easily do this with Microsoft.Office.Interop.Excel by
ExcelApp.visible = true;. However, this module requires users to release every COM object generated. Otherwise, the objects remain and eat up memory. This is the reason I prefer to use NPOI.
How can I achieve this? Any answers would be appreciated.
You cannot do this with NPOI. NPOI reads and writes data from serialized Excel files. You cannot access those files while Excel has them open, and even if you could, Excel simply wouldn't re-read the files so your modifications wouldn't show up.
The problem you describe comes down to "I want to interact with a running Excel instance without using Excel interop". That's not going to work.
Hello I am looking for a way to open an Excel sheet programmatically and allow the user to be able to select a range of cells. My reasoning behind this is I am currently developing a lot of individual excel upload forms for pulling data in to a database I would like the ability to select the column headers as simply as highlighting the cells through excel and presenting a textbox for each to enter the equivalent DB table column name and store these. So effectively a form to create a form.
Many thanks
Charlie
Please check this article: Opening and Navigating Excel with C#.
There is also a section in MSDN library that completely covers Excel PIA.
Need to create a application in C# with Win Forms the applications need to do the following:
1.Open a excel workbook in the background the user should not see this step
2. Then save the data in some way to the application so it can be accessed later
3. Receive a 8 digit identification code from a text box and search for a entry in the excel workbook containing the same digit
4.When the relevant entry is found the application should write the current time and date to a cell Sign-In and at the specific date the entry is done.
5. The application should then save the workbook automatically and
6.Then close the application.
Can anyone help me please the Microsoft.Office.Interop is very complicated.
Try closedXML, it sits on top of Excel Interop and makes things easier.
But with out any examples of what you have tried it is really hard to tell you how to accomplish what you want.
If you don't have old-excel support (.xls), you can use Wrapper.OpenXml which available as Nuget package.
I have a spreadsheet that I'd like to compile into a form that I could call from C#.
Naturally, I'd like to be able to change the inputs to the spreadsheet before reading the calculated result.
What is your recommended method?
UPDATE:
To clarify, I want to make an existing Excel spreadsheet available as a web service that is callable from .NET. I can't have a dependency on Excel, as its running on a web server.
UPDATE:
I used the answer below, and it worked like a charm. Now I can prototype a formula in Excel, then convert it straight into C# and compile it into an assembly.
This question is also covered under Reading Excel Files as a Server Process.
FlexCel API Mate within TMS Flexcel Studio for .NET lets you convert an existing Excel spreadsheet into C# code, recalculate the spreadsheet, and read the result out of a cell using an API call.
See the video tutorial of FlexCel ApiMate. The video states, quote:
ApiMate will convert an Excel file
into a C#, VB.NET or Delphi.NET
program.
The docs also state:
Recalculation of more than 200 Excel
functions.
and:
You can add your own functions on the
code to the already big list
implemented by FlexCel, and use them
as native functions in your report.
UPDATE
Here is clarification from TMS tech support:
Emailed question:
I'd like to do the following:
Convert an existing .xlsx file to C# code, importing data from a database.
Allow FlexCel to recalculate the spreadsheet for me.
Read an answer out of a cell (for use elsewhere in my C# code).
Skip the step of writing the finished .xlsx file to the disk (we don't need this).
In short, I want to use FlexCel as an "Webserver Excel calculation engine", so we don't have to have Excel installed on the web server to perform spreadsheet calculations.
Are the steps I've described possible? Or have I misunderstood how the component works?
Emailed reply:
You can either load the file directly from the database (by opening from a stream) or use the APIMate tool (incuded in the tools folder) to convert the file to c# code.
Yes, FlexCel will recalculate it with XlsFile.Recalc()
Yes, you can read the recalculated values too.
Yes, you don't need to write the answer if you don't want to.
Besides this, for using it as recalculation engine, we have the "RecalculateCell()" method that won't recalculate the full spreadsheet, but only the cells needed to get the value in an specific cell. So, if for example your result is in A1, you can call RecalcCell in A1, and it will recalculate only all cells needed to get the value in A1 (including dependecies, so if A1 has a formula with a2, and a2 with a3, all 3 will be calculated).
There is also a RecalcExpression method, that will recalculate the value of any formula without needing to write it into a cell. So imagine you have a column of numbers at col A, and you want to know the sum. You could use RecalcExpression("=sum(A:A)"); to know the sum, without needing to enter a formula in B1 with the sum and then reading the value of that formula (which you could also do of course)
From Microsoft, there appears to be a framework called Excel Services "Develop A Calculation Engine For Your Apps"
Teaser excerpt:
This article discusses:
Excel as a server-based application
The Excel Services architecture and APIs
Creating managed user-defined functions
Building custom solutions with Excel Services
I have never used it, but the info-graphics on the main page are most encouraging.
Thanks for asking this :)
Calc4web converts spreadsheets into C++ code, which can be called from C#, Java, etc.
Quote from website:
Calc4Web gives programmers a better
way to get their job done: create a
small spreadsheet which holds the
logic, and push a button to turn that
spreadsheet into C++ code that works
on the first try, code that can be
called from any language: C,C++, C#,
Visual Basic, Java, and any other
language which can call into DLLs.
I also suspect that since it compiles the spreadsheet logic to purely native C++ code, it will be very fast compared to Excel (the website states "5,000 times faster").
Check out ActiveMesa X2C, a tool for converting Excel spreadsheets into C# and C++. (Disclaimer: I'm the author.)
For a list of Spreadsheet components that allow you to work with Excel spreadsheets without having a dependency on Excel, see DevDirect Spreadsheet Components.
SyncFusion Essential Calculate.
Quote:
... you can fully load,
manipulate, and compute Excel
spreadsheets with no dependence on
Excel.
There is no way to compile an excel spreadsheet into c# code.They are not in any way the same "thing", In the same way you can't compile this text that you are reading, or a word document into code or an assembly of some kind.
You have to be more specific with the kind of functionality you want to get, which will help you get an answer.
There are several ways (pointed out in other answers here) to allow you to access Excel spreadsheet data and utilize them, but this is in no way compiling them.
Is it possible to import excel data to display using C# in any view(data grid etc ..) while retaining formatting like Bold, italic and strikethrough, throughout the document? I am making a Windows form application. My data is in an excel sheet, I want to display it in grid view or any other while retaining the formatting.
Well, there are some ways that I can think of but neither of them are very pretty at all and they would not be very effecient.
1) Parse the excel file cell by cell using Excel Interop. (Very nasty)
2) If you can convert the excel file to Excel XML you could then write say a XSLT to parse the file to pull styling data much more quickly.
Of course getting the styling data out is one thing. Applying it can be a whole other experience. Once you get the styling you have to make sure you apply the values to all the correct columns. Again very nasty and alot of parsing.
However since you did not say whether this was a web or desktop app you could always just embedd an excel control (on the web side) to display the data which may solve your problem. On a desktop app you are probably in for a world of pain trying to do what I describe above.
Maybe somebody will have a better answer but that's what I got.
SpreadsheetGear for .NET can load Excel workbooks and provides access to formatted text values as well as cell formatting such as fonts and colors.
SpreadsheetGear also comes with a Windows Forms spreadsheet control which will allow users to display, edit, format, calculate, print, etc... workbooks with formatting, charts, etc... intact.
If you are building an ASP.NET application, you can use SpreadsheetGear to open a workbook and generate an image of cells and / or charts as shown on our "Excel Chart and Range Imaging Samples" page here
You can download the free trial here if you want to try it out.
Disclaimer: I own SpreadsheetGear LLC