Refresh how-to-open-files-using-the-openfiledialog-component

[v-thepet]

Summary

Refreshed content and new code samples for review.

New code samples are in PR dotnet/samples#674.

Fixes #Issue_Number (if available)
See Task https://mseng.visualstudio.com/TechnicalContent/_queries/edit/1409952/?triage=true

[v-thepet]

@rpetrusha - This is ready for your review, please see email. (I'll remove the code examples to the samples repo once we're sure where to put them.) Thanks.

[rpetrusha]

This looks good, @v-thepet. I've left a number of comments and suggestions.

[rpetrusha]

I think I have the latest version of the 3.0 SDK (3.0.100-preview-010184), but this element isn't present.

[v-thepet]

@rpetrusha - It looks like the .csproj file generated by Visual Studio 2019 does differ from the .csproj file generated by Visual Studio Code (although I thought I'd compared them). The VS Code-generated file has the "namespace" element and the VS file doesn't. Given the discrepancy, how about leaving out this code entirely and just say that they need to have a .NET Core Windows Forms project file.

[rpetrusha]

Suggested change

	Application.Run(new OpenFileDialogForm());
	Application.EnableVisualStyles();
	Application.SetCompatibleTextRenderingDefault(false);
	Application.Run(new OpenFileDialogForm());

The two lines should also be added to Main in the second example for both VB and C#.
Also need to add this code to the second set of files.

[v-thepet]

@rpetrusha - Application.SetCompatibleTextRenderingDefault(false); throws a runtime error unless it is the first thing in the file so I attempted to rearrange things.

[rpetrusha]

@v-thepet, sample code can go in samples/snippets/winforms/open-files/example1/cs and samples/snippets/winforms/open-files/example1/vb for the first example, and samples/snippets/winforms/open-files/example2/cs and samples/snippets/winforms/open-files/example2/vb for the second example.

In terms of files to commit, there's no need for program.cs if the main source code file contains the entry point. There's also no need for the *.resx file, since the examples use no resources. There's also no need for the code-behind *.Designer.cs file if all necessary initialization is handled in the constructor.

It would be a good idea to replace the message box with a text box, and probably in the initialization code to better place the controls in the window.

[v-thepet]

@rpetrusha - I think I've got all the changes, please re-review. I will put the examples up on samples where you designated, but since there is a lot new, I left them here for now for expediency. Thanks.

[rpetrusha]

This looks good, @v-thepet. I think that the next step is to check the examples into the dotnet/samples repo, add code references to the samples repo here, and then rebuild when the samples merge.

[v-thepet]

@rpetrusha - The code links are now in the article replacing the embedded code. The code PR is dotnet/samples#674. Thanks.

[rpetrusha]

Closing and reopening to begin new build after dotnet/samples#674 was merged.

[rpetrusha]

This looks good, @v-thepet. Thanks for all the work you've put into improving this article. I'll merge your PR now.