How to POST using HTTPclient content type = application/x-www-form-urlencoded

Question

I am currently developing a wp8.1 application C#, i have managed to perform a POST method in json to my api by creating a json object (bm) from textbox.texts. here is my code below. How do i take the same textbox.text and POST them as a content type = application/x-www-form-urlencoded. whats the code for that?

Profile bm = new Profile();
bm.first_name = Names.Text;
bm.surname = surname.Text;

string json = JsonConvert.SerializeObject(bm);

MessageDialog messageDialog = new MessageDialog(json);//Text should not be empty 
await messageDialog.ShowAsync();

HttpClient client = new HttpClient();
client.DefaultRequestHeaders.Clear();
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
client.DefaultRequestHeaders.TryAddWithoutValidation("Content-Type", "application/json");

byte[] messageBytes = Encoding.UTF8.GetBytes(json);
var content = new ByteArrayContent(messageBytes);
content.Headers.ContentType = new MediaTypeHeaderValue("application/json");
var response = client.PostAsync("myapiurl", content).Result;

score 343 · Answer 1 · edited Jul 21 '23 at 14:30

343

var nvc = new List<KeyValuePair<string, string>>();
nvc.Add(new KeyValuePair<string, string>("Input1", "TEST2"));
nvc.Add(new KeyValuePair<string, string>("Input2", "TEST2"));
using var client = new HttpClient();
using var req = new HttpRequestMessage(HttpMethod.Post, url) { Content = new FormUrlEncodedContent(nvc) };
using var res = await client.SendAsync(req);

Or

var dict = new Dictionary<string, string>();
dict.Add("Input1", "TEST2");
dict.Add("Input2", "TEST2");
using var client = new HttpClient();
using var req = new HttpRequestMessage(HttpMethod.Post, url) { Content = new FormUrlEncodedContent(dict) };
using var res = await client.SendAsync(req);

edited Jul 21 '23 at 14:30

Charlieface

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answered Apr 01 '17 at 14:52

Ray Krungkaew

6,652
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19

You can also pass a dictionary to the constructor of `FormUrlEncodedContent`, since Dictionary is an `IEnumerable` of `KeyValuePair`s. – Sam Magura Jul 17 '17 at 13:09
Using ***await*** in Task method ? – Kiquenet Oct 27 '17 at 13:03
2

@Kiquenet yes, in "async Task" method – Ray Krungkaew Oct 30 '17 at 04:03
1

The StringContent technique failed: `new StringContent(jsonString, Encoding.UTF8, "application/x-www-form-urlencoded")` and the KeyValuePair worked! – Benxamin Apr 12 '22 at 23:19
Your KeyValuePair example worked. You have made my day! – Gail Foad Oct 03 '22 at 14:20

score 68 · Answer 2 · edited Jul 30 '21 at 20:08

68

 var params= new Dictionary<string, string>();
 var url ="Please enter URLhere"; 
 params.Add("key1", "value1");
 params.Add("key2", "value2");
             
 using (HttpClient client = new HttpClient())
 {
    client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

    HttpResponseMessage response = client.PostAsync(url, new FormUrlEncodedContent(params)).Result;
    var token = response.Content.ReadAsStringAsync().Result;
}
               
//Get response as expected

edited Jul 30 '21 at 20:08

John Nyingi

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answered Jun 20 '18 at 07:24

Bhushan Teli

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How `params` became `dict` ? – joystick Jun 08 '21 at 08:36
2

Please note that HttpClient should be reused, not be disposed. https://learn.microsoft.com/en-us/dotnet/api/system.net.http.httpclient#instancing – NiKiZe Feb 01 '23 at 13:41

score 25 · Answer 3 · answered May 29 '20 at 15:07

The best solution for me is:

// Add key/value
var dict = new Dictionary<string, string>();
dict.Add("Content-Type", "application/x-www-form-urlencoded");

// Execute post method
using (var response = httpClient.PostAsync(path, new FormUrlEncodedContent(dict))){}

score 0 · Answer 4 · answered Feb 12 '21 at 16:47

0

Another variant to POST this content type and which does not use a dictionary would be:

StringContent postData = new StringContent(JSON_CONTENT, Encoding.UTF8, "application/x-www-form-urlencoded");
using (HttpResponseMessage result = httpClient.PostAsync(url, postData).Result)
{
    string resultJson = result.Content.ReadAsStringAsync().Result;
}

answered Feb 12 '21 at 16:47

Alexandru Dicu

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Please don't use .Result instead of await – Brad Firesheets Jan 10 '23 at 19:20

How to POST using HTTPclient content type = application/x-www-form-urlencoded

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