.NET

The .NET 9 RC-1 was released on September 9, 2024. Now, when you upgrade from .NET x to .NET 9, properties in WinForms components throw an error.

WFO1000 - Property 'YourProperty' does not configure the code serialization for its property content

To fix this problem, you need to add a code in your C# file.

Add the using

using System.ComponentModel;

And on each property, the tag DesignerSerializationVisibility, like below.

[DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]    
public string MyProperty { get; set; }

However, you can also suppress the warning by adding WFO1000 to the NoWarn property in your project property file.

Error

More information can be accessed here.