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

Question

My code:

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();
}

My json string includes an base64 encoded image so the FormUrlEncodedContent throws the exception :

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

Important is that the server expects exact this format with "parameter" as post key and the json as the post value. How can I bypass this limitation of FormUrlEncodedContent?

Have you looked at what is being transmitted over the wire with a debugger, such as [Fiddler](http://www.fiddlertool.com)? — Rowland Shaw, Dec 09 '15 at 11:56
There is not anything being transmitted because the exception is thrown before — ManfredP, Dec 09 '15 at 12:12
So what Uri does the debugger tell you is being passed to `PostAsync`? — Rowland Shaw, Dec 09 '15 at 12:23
The URI is ok because with a shorter string all works fine. Only with a large base64 string from an image the exception is thrown — ManfredP, Dec 09 '15 at 12:38
as i mentioned in my post, in "FormUrlEncodedContent" method — ManfredP, Dec 09 '15 at 13:01
Possible duplicate of [How to set large string inside HttpContent when using HttpClient?](http://stackoverflow.com/questions/23703735/how-to-set-large-string-inside-httpcontent-when-using-httpclient) — Rowland Shaw, Dec 09 '15 at 13:18
You can't do it. So you have to do something else. What are the possibilities of doing it differently? — , Dec 09 '15 at 14:13
Thanks to all, [this post solved my problem](http://stackoverflow.com/questions/6695208/uri-escapedatastring-invalid-uri-the-uri-string-is-too-long/10755250#10755250) — ManfredP, Dec 10 '15 at 15:54
Hi ManzMoody, May i know how you fix this issue. I'm stuck in the ditto same issue. — Srini, Jan 31 '17 at 07:44

score 0 · Accepted Answer · answered Feb 01 '17 at 10:26

I solved this issue with the following method which replaces FormUrlEncodedContent :

// 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();
}

Does not work with the HttpClient - Assembly System.Net.Http, Version=1.5.0.0, — NBaua, Jun 24 '17 at 06:29

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

1 Answers1