Since a month ago, my VS doesn't seem to want to display the summary info in tooltips for any system methods or classes when I hover them with my mouse.
I had ReSharper installed and started noticing this problem. I assumed that ReSharper disabled the default method descriptions, so I wasn't thinking much further about it, only considering it a mere annoyance.
After removing ReSharper though, the problem persisted.
VS now only shows descriptions for my own methods which I've added a <summary> tag for and any descriptions from NuGet packages, but not system methods like Where, Encoding.GetString, etc.
I've tried repairing VS, resetting settings, un-/checking checkboxes in Options > Text Editor > General, but to no avail.
Has anyone had a similar problem?
This looks more like a framework issue rather that a VS/R# issue. If neither one of them can load the description strings, it probably means the description XML files are missing.
Check if you see the XML files in:
C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.5.2
If you don't, then reinstall the framework to fix the issue.
Link to .NET Framework 4.5.2 Developer Pack: https://www.microsoft.com/en-us/download/details.aspx?id=42637
Try to activate the 'Statement completion' checkboxes in Options > Text Editor > All Languages > General as in the following screenshot:
Also, check that your project is referencing the libraries in the C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\ folder. You can do that by selecting each project reference and viewing it in the property window, or by editing your project file with a text editor.
I had one case where my project had references to the actual runtime framework located at C:\Windows\Microsoft.NET\Framework\ which does not have the associated .xml files.
来源：https://stackoverflow.com/questions/37500027/visual-studio-not-showing-intellisense-descriptions-anymore