String too large for FormUrlEncodedContent() in Windows Phone 8 Post 上传

String too large for FormUrlEncodedContent() in Windows Phone 8 Post upload

我的代码:

string json = BuildJson(uploadItem);

using (var client = new HttpClient())
{
    var values = new List<KeyValuePair<string, string>>();
    values.Add(new KeyValuePair<string, string>("parameter", json));

    var content = new FormUrlEncodedContent(values);
    var response = await client.PostAsync(App.Current.LoginUrl, content);

    var responseString = await response.Content.ReadAsStringAsync();
}

我的 json 字符串包含 base64 编码图像,因此 FormUrlEncodedContent 抛出异常:

" Invalid URI: The Uri string is too long".

重要的是服务器期望使用 "parameter" 作为 post 键和 json 作为 post 值的确切格式。如何绕过 FormUrlEncodedContent 的限制?

我使用以下替换 FormUrlEncodedContent 的方法解决了这个问题:

// URI Escape JSON string
var content = EscapeDataString(json);

private string EscapeDataString(string str)
{
    int limit = 2000;

    StringBuilder sb = new StringBuilder();
    int loops = str.Length / limit;

    for (int i = 0; i <= loops; i++)
    {
        if (i < loops)
        {
            sb.Append(Uri.EscapeDataString(str.Substring(limit * i, limit)));
        }
        else
        {
            sb.Append(Uri.EscapeDataString(str.Substring(limit * i)));
        }
    }

    return sb.ToString();
}