以下类已正确保存/读回：

public class Foo
{
    public string Name { get; set; }
 
    public string MashupString { get; set; }
 
    public override string ToString()
    {
        return Name;
    }
}

注意：我不需要SerializableAttribute.

编辑：这是xml输出：

<WindowsFormsApplication1.MySettings>
    <setting name="Foos" serializeAs="Xml">
        <value>
            <ArrayOfFoo xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                xmlns:xsd="http://www.w3.org/2001/XMLSchema">
                <Foo>
                    <Name>Hello</Name>
                    <MashupString>World</MashupString>
                </Foo>
                <Foo>
                    <Name>Bonjour</Name>
                    <MashupString>Monde</MashupString>
                </Foo>
            </ArrayOfFoo>
        </value>
    </setting>
</WindowsFormsApplication1.MySettings>

我使用的设置类：

sealed class MySettings : ApplicationSettingsBase
{
    [UserScopedSetting]
    public List<Foo> Foos
    {
        get { return (List<Foo>)this["Foos"]; }
        set { this["Foos"] = value; }
    }
}

最后我插入的项目：

private MySettings fooSettings = new MySettings();
 
var list = new List<Foo>()
{
    new Foo() { Name = "Hello",MashupString = "World" },new Foo() { Name = "Bonjour",MashupString = "Monde" }
};
 
fooSettings.Foos = list;
fooSettings.Save();
fooSettings.Reload();