Csharp 尽管保证密钥不同，但已添加相同密钥的项(&Q；)

无论何时调用Define类中的任何内容，下面的代码似乎都会得到System.TypeInitializationException.这些对保证是不同的，如下所示，并且没有任何代码以任何方式修改词典.然而，每次都会抛出错误ArgumentException: An item with the same key has already been added. Key: Key1.有什么原因会发生这种情况吗？

public static class Define
{
    public static readonly Dictionary<DefineChoices, string> Definitions = new([Pair1, Pair2]);

    public enum DefineChoices
    {
        Key1,
        Key2
    }

    public static readonly KeyValuePair<DefineChoices, string> Pair1 = new(DefineChoices.Key1, "string1");
    public static readonly KeyValuePair<DefineChoices, string> Pair2 = new(DefineChoices.Key2, "string2");

堆栈跟踪如下:

Unhandled exception. System.TypeInitializationException: The type initializer for 'Program.Namespace.Define' threw an exception.
 ---> System.ArgumentException: An item with the same key has already been added. Key: Key1
   at System.Collections.Generic.Dictionary`2.TryInsert(TKey key, TValue value, InsertionBehavior behavior)
   at System.Collections.Generic.Dictionary`2.Add(TKey key, TValue value)
   at System.Collections.Generic.Dictionary`2.AddRange(IEnumerable`1 enumerable)
   at System.Collections.Generic.Dictionary`2..ctor(IEnumerable`1 collection, IEqualityComparer`1 comparer)
   at System.Collections.Generic.Dictionary`2..ctor(IEnumerable`1 collection)
   at Program.Namespace.Define..cctor() in FilePath\Define.cs:line 2
   --- End of inner exception stack trace ---