System.Drawing中Graphics/Brushes/Bitmap失效，仅PointF正常的问题求助

Hey, let's work through this System.Drawing issue you're facing — it's a super common gotcha, especially with newer .NET versions, so I’ve got a few targeted fixes to try out:

1. You’re probably using a .NET version that doesn’t include System.Drawing.Common by default #

Starting with .NET 6, System.Drawing.Common was moved out of the core framework (even on Windows). If your project is on .NET Core/.NET 5+, you’ll need to manually add the NuGet package:

• Right-click your project → Manage NuGet Packages, search for System.Drawing.Common, and install the latest stable version.
• Or run this command in the Package Manager Console:

  Install-Package System.Drawing.Common
  

2. Double-check your namespace references #

Even if PointF works, Graphics, Brushes, and Bitmap rely on the full System.Drawing namespace being imported. Make sure these lines are at the top of your code file:

using System.Drawing;
using System.Drawing.Drawing2D; // Optional, but needed for advanced drawing features

Missing these will make the compiler act like those classes don’t exist.

3. Fixing the empty Reference Manager #

An empty Reference Manager usually ties back to project type or framework compatibility:

• Check your target framework: Right-click the project → Properties → Application → Target Framework. If you’re using a generic .NET 6/7/8 (not the Windows Desktop variant), the Reference Manager will be limited — switch to a Windows-specific framework (like .NET 6 Windows Desktop) or use the NuGet package method above.
• Refresh your project: Sometimes Visual Studio’s cache glitches. Right-click the project → Unload Project, then right-click again → Reload Project. That often fixes missing references in the manager.

4. Ensure you have the right SDK components installed #

For Windows Forms/WPF projects, make sure you’ve got the necessary Windows SDK bits in Visual Studio:

• Open the Visual Studio Installer → Modify → Under ".NET Desktop Development", check all relevant components (especially Windows Forms SDK).

Quick Troubleshooting Checklist #

1. Uninstall any existing System.Drawing references if they’re present.
2. Install the System.Drawing.Common NuGet package.
3. Clean your solution (Build → Clean Solution) then rebuild it (Build → Rebuild Solution).
4. Restart Visual Studio — cached data can sometimes mess with reference detection.

After going through these steps, Graphics, Brushes, Bitmap, and the Reference Manager should start behaving as expected.

内容的提问来源于stack exchange，提问作者nymda