14 April 2016 13:42
I've seen a lot of questions about the best way to import data from uploaded Excel files to a SQL Server database in an ASP.NET application. Most solutions involve the use of the JET or ACE OLEDB providers to read data from the saved Excel file, and some even show how to use Office Interop to obtain the data. However, all of these solutions rely on additional components being installed on the server, and they also require the uploaded file to be saved somewhere, even temporarily, which creates an additional maintenance task. The solution that follows makes use of a Nuget package that gets deployed with your application and can work with streams, so the uploaded file doesn't need to be saved. It is, in my submission, THE best way to import data from uploaded Excel files to SQL Server in an ASP.NET application.
23 July 2015 20:05
There are a number of reasons why you might get "The 'Microsoft.ACE.OLEDB.12.0' provider is not registered on the local machine" error when attempting to connect to either an accdb or an xlsx file, depending on what you are doing. This article discusses some of the causes and provides solutions first for uses involving ASP.NET, and then looking at other application uses.
07 July 2015 13:49
There are countless articles that demonstrate exporting ASP.NET GridViews to Excel. They pretty much all do the same thing - they use the RenderControl method to generate HTML and then save it to a file with a .xls extension. This kind of works, but the resulting file is actually an HTML file masquerading as an Excel file. And that has two flaws: it cannot be used as a data source because providers complain that it is not in an acceptable format, and users of Office 2007 or newer are always confronted with a warning about the contents of the file when they try to open it, causing confusion, suspicion or annoyance. This article shows how to use the free, open source library to export the content of a GridView control to a genuine .xlsx file that doesn't suffer these problems.
30 June 2015 14:47
This article allows me the opportunity to demonstrate a feature of my newest favourite open source library: EPPlus. EPPlus is a .net library that reads and writes Excel 2007+ files using the Open Office Xml format (xlsx). This fantastic, easy to use (and free) library enables the use of Excel in ASP.NET applications without the need to install the Access Database Engine (ACE) or having to mess about with unsupported Office Automation on the web server (assuming you can even get Office installed there). Prompted by a rash of similar questions that appeared on the ASP.NET forums recently, this article looks at reading the contents of an uploaded Excel file without saving it, and displaying the data in a Web Forms GridView.