LINQ to SQL DBML file shows up as XML code in Visual Studio Community 2017
I have a project from a few years ago that I am looking back into again, and while it builds just fine in Visual Studio Community 2017, when I open the DBML file, I get a big XML file instead of a nice design surface with the data tables.
The solution to this issue is to install the correct component to handle this type of file. To do this, you need to exit Visual Studio IDE and then launch the Visual Studio Installer. Once there, click Modify, click the Individual components tab at the top, scroll down to the Code tools section, select LINQ to SQL tools so that there is a check mark next to it, and click the Modify button at the bottom right corner of the window. Once this finishes and you go back into Visual Studio, the DBML file should now show up as a design surface instead of XML source code.
BTW, a posthumous Happy Birthday to Gilda Radner, who left us far too soon.