Calling Win32 API from .NET C# Application

As quoted in the useful reference below:

"Anybody doing any serious Windows development in C# will probably end up calling many Win32 functions. The .NET framework just doesn't cover 100% of the Win32 API." - Mike Thompson

This illustrative example here is simply to show what the integrated code looks like; however identifying available drive space is a common app requirement

The interop of .NET and Win32API works by way of referencing the InteropServices .NET namespace and using normal Win32 API functions with the [DllImport()] attribute denoting the Win32 API assembly being used and the corresponding function being modified as "static extern" which informs the compiler that the function is calling unmanaged (non-.NET) code.

 using System;  
 using System.Runtime.InteropServices;  
 namespace ConsoleApp1  
 {  
   internal static class Win32  
   {  
     [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]  
     internal static extern bool GetDiskFreeSpaceEx(string drive, out long freeBytesForUser, out long totalBytes, out long freeBytes);  
   }  
   class Program  
   {  
     static void Main(string[] args)  
     {  
       long freeBytesForUser;  
       long totalBytes;  
       long freeBytes;  
       Console.WriteLine("Free space in this directory:");  
       if (Win32.GetDiskFreeSpaceEx(@"C:\", out freeBytesForUser, out totalBytes, out freeBytes))  
       {  
         Console.WriteLine("Free user bytes: " + freeBytesForUser.ToString());  
         Console.WriteLine("Free total bytes: " + totalBytes.ToString());  
         Console.WriteLine("Free bytes: " + freeBytes.ToString());  
       }  
       Console.ReadLine();  
     }  
   }  
 }  

Reference: https://stackoverflow.com/questions/137255/how-can-i-determine-if-a-remote-drive-has-enough-space-to-write-a-file-using-c

ETL and the Case Against a Single System for All Business Processes

Nearly every business wants to centralize their business data so that they can get an at-a-glance overview of what is going on at any given point in the day. Suppose, for instance, a company has its business data on 5 separate database servers, in various databases therein, across several different tables. And much of the data will need to be slightly modified (transformed) in order to make data types consistent and optimize it for quick and meaningful data analysis.

Assume the database servers are:

• CMS, Orders (Dynamics 365 data)
• Accounting (Sage 50 data)
• Warehouse, Logistics (SAP data)
• Field Service, Product Support (SalesForce data)
• Call Center (TantaComm data)

Furthermore, the business wants to apply some custom logic to various fields so that certain calculations don't have to be made by the OLAP end users and applications.

ETL is just moving data from a Source to a Destination, often making some changes (transformations) along the way

Well, it all seems so complicated, right? How can all that disparate data be combined and standardized? It's not as complicated as allowing an ERP solution define how your various departments do their job. Some ERP products truly do have the functionality to satisfy 80-85% of the company business requirements. And when that is the case, by all means, companies should go that route.

But for instances where ERP of every business function is not working, you can use products like SSIS, Informatica, and Oracle Data Integrator to easily map ETL data visually and apply code operations to the data using a variety of programming languages.

But of course, there is no "one-size-fits-all 100% of our business needs" ERP solution; different business productivity software work better or worse for different industries, different departmental needs, for all manner of different reasons. Why care about the choice of business tool that your business' management and best minds know and have proven is most effective for their- often very specific- job?

Allowing a business to integrate the "best apps for each particular type of job" is nothing more than a sort of microservices architecture. But if we are working with custom code in these various LOB applications (at least some of the LOB apps will need custom API integrations so that they can talk to each other), with each new block of custom code, comes more decentralized code bases and decentralized test scripts...

All considered, I would argue that trying to put square pegs into round holes a la "ERP-everything" is a much, much, MUCH bigger effort than a well-developed and tested scheduled ETL Data Warehouse refresh process to centralize your company's data.

It's always a balance with software. Use the most effective apps for your organization and departmental requirements, but try to avoid the dependency hell that can come along with a poorly managed distributed application environment.

Here are the ETL steps in order, from the resource link below:

Extract the data from the external data sources such as line-of-business systems, CRM systems, relational databases, web services, and anywhere you have business data you want to summarize.

Transform the data. This includes cleansing the data and converting it to an OLAP-friendly data model. The OLAP-friendly data model traditionally consists of dimension and fact tables in a star or snowflake schema.

Load the data so that it can be quickly accessed by querying tools such as reports, dashboards, etc.

"90% of the requirements now is better than 100% of the requirements never" -Unknown

Reference: https://blogs.msdn.microsoft.com/andreasderuiter/2012/12/05/designing-an-etl-process-with-ssis-two-approaches-to-extracting-and-transforming-data/

Visual Studio Config Transforms

When you are working on software that needs to target different resources for different environments (ie. local, DEV, STAGE, PRODUCTION), you can easily manage your VS project environment through the use of .config transformation files.

Here is your default web.config:

Simply make an alternate version (with the same name) of the element you wish to change in your various configuration transformations (web.DEBUG.config, web.Development.config, etc.). In this example, we are setting up a transform to change the connection string that has the name, "applicationConnStr":

NOTE: The same configuration element (the same name, specifically) you want to transform must be in the base web.config file.

By default, the transformation we have set up will only be applied when the project is published. In order to get the transformations working with each build, you must edit the bottom of the *.csproj file with the following Target:

  <Target Name="BeforeBuild">

    <TransformXml 

        Source="Web.Base.config" 

        Transform="Web.$(Configuration).config" 

        Destination="Web.config" />

  </Target>

And be sure to uncomment the code, it is commented out by default. Now select a different build configuration, build your project, and you should see the "applicationConnStr" transformed to match the element from the web.config.[Debug||Release||etc.] that you selected to Build:

To add new web.config transform files, just right click on the web.config file and select "Add Config Transformation".

To associate your transformations with different builds, under the Build Dropdown, select "Configuration Manager..." and configure as you like:

Setting up build configurations that point to different web.configs (actually web.config "transforms") allows you to debug and run code according to your needs (ie. show DEMO at a meeting, Debug Development to uncover a bug, point to local for ongoing development, etc.).

ASP.NET Core has a very different configuration setup that uses JSON objects and more configurable things in .NET Core Startup.cs; this reference is for .NET Standard.

The key in all of this is the name of the element you are matching and then replacing. It just has to match in both places and all will be transformed on your application's web.config. In this example, we matched and replaced the value for a config element with the name, "applicationConnStr".

In a real-world scenario, there are many things that we could dynamically replace through config transforms: database connection strings, image servers, mail servers, file shares, printer locations, encryption keys, etc.).

Reference: https://docs.microsoft.com/en-us/aspnet/web-forms/overview/deployment/visual-studio-web-deployment/web-config-transformations