将哈希表更改为字典

我已经读过了。但是，没有任何实例可以使它起作用。所以我自己尝试了。这是我的代码：

public void AskServer(List<Kvp> kvps)
{
    WWWForm form = new WWWForm();
    Hashtable headers = form.headers;
    if (this._lastCookies != string.Empty) {
        headers.Add("Cookie", this._lastCookies);
    }
    foreach (var arg in kvps) {
        form.AddField(arg.Key, arg.Value.ToString());
    }
    form.AddField("pseudo", this._pseudo);
    form.AddField("jeton", this._dernierJeton.ToString());
    StartCoroutine(SendToServer(
        new WWW(this._URL, form.data, headers)
    )); 
}

现在，有一个警告说，调用newWWW(this._URL, form.data, headers)已过时，我应该在字典中使用那个。声明如下：

    public WWW(string url, byte[] postData, Dictionary<string, string> headers);
    [Obsolete("This overload is deprecated. Use the one with Dictionary argument.")]
    public WWW(string url, byte[] postData, Hashtable headers);

因此，当我尝试在问题开头提供的链接中使用该示例时，我有这样的代码，该代码不起作用：

public static Dictionary<K, V> HashtableToDictionary<K, V>(Hashtable table)
{
    return table
      .Cast<DictionaryEntry>()
      .ToDictionary(kvp => (K)kvp.Key, kvp => (V)kvp.Value);
}

public void AskServer(List<Kvp> kvps)
{
    WWWForm form = new WWWForm();
    Dictionary<string, string> headers = StateManager.HashtableToDictionary<string, object>(form.headers);
    if (this._lastCookies != string.Empty) {
        headers.Add("Cookie", this._lastCookies);
    }
    foreach (var arg in kvps) {
        form.AddField(arg.Key, arg.Value.ToString());
    }
    form.AddField("pseudo", this._pseudo);
    form.AddField("jeton", this._dernierJeton.ToString());
    StartCoroutine(SendToServer(
        new WWW(this._URL, form.data, headers)
    )); 
}

错误是：Assets/Code/StateManager.cs(58,36): error CS0029: Cannot implicitly convert typeSystem.Collections.Generic.Dictionary'到System.Collections.Generic.Dictionary<string,string>'

我究竟做错了什么？有没有更有效的方法呢？