C# – 当引用类常量时,为什么执行会流向实例变量？

我的问题是两部分;为什么会发生这种情况,我该如何解决呢？我试图创建两个部分类,一个仅用于常量,另一个用于其他一切,但执行仍然继续到另一个部分类来实例化单例.

public sealed class Foo
{  
    public static readonly string FILE_LOCATION = @"pathtofile";

    // (singleton code modeled after:
    // http://csharpindepth.com/articles/general/singleton.aspx --fourth     version)
    private static readonly Foo foo = new Foo();

    // Rest of class implementation...
 }

该属性是在按钮单击时从表单类的实例引用的：

public partial class MyForm : Form
{
    public void button1_Click(object sender,EventArgs e)
    {
        string s = Foo.FILE_LOCATION;
        // this location is only reached AFTER the singleton is instantiated.
    }
}