C# MD5杀毒程序问题：选中文件夹路径无法读取

I've developed an MD5 antivirus program using C#, Visual Studio 2017, Windows Forms, and .NET Framework 4.5. The program's core function is to read a list of strings from a text file, then compare them against the MD5 hashes of target files to detect potential viruses. This is purely a personal project for my own enjoyment—no plans to sell it or distribute it commercially.

Right now, I'm stuck with two frustrating issues:

• When a user selects a folder, only a message box can successfully read the selected path. My list box just displays empty strings instead of the files or relevant content I’m trying to populate it with.
• The MD5 hash values for scanned files are always coming up empty, no matter which files I target for checking.

I’d really appreciate any guidance or tips to work through these problems!

内容的提问来源于stack exchange，提问作者user9475900