how to use Management API in Windows Form / C# - but The remote server returned an error: (400) Bad Request - c#-4.0

Question

I have a problem in API Management, I want to create images in item 1 item, but I still can not do it forever. I use c # language, I feel depressed
i want to create a resource in catchoom.
can you help me
byte[] buffer = null;
byte[] data = null;
byte[] data1 = null;
HttpWebRequest request = null;
int bytesRead = 0;
long length = 0;
string boundary = DateTime.Now.Ticks.ToString("x");
// string boundary = "AaB03x";
StringBuilder sb = null;
// Create the HttpWebRequest object
request = (HttpWebRequest)HttpWebRequest.Create("https://crs.catchoom.com/api/v0/image/?api_key=5aba12ba6974c04ebc95da45ba1597d27d75238f");
// Specify the ContentType
request.ContentType = "multipart/form-data; boundary=" + boundary;
request.Accept = "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8";
// Specify the Method
request.Method = "POST";
request.KeepAlive = false;
// Create the StringBuilder object
sb = new StringBuilder();
// Constrcut the POST header message
sb.AppendLine("");
sb.AppendLine("--" + boundary);
sb.AppendLine("Content-Disposition: form-data; name=\"anh\"");
sb.AppendLine("");
sb.AppendLine("/api/v0/item/aee726ff67274fcb80f4c24f27861c1e/");
sb.AppendLine("--" + boundary);
sb.AppendLine("Content-Disposition: file; name=\"anh\"; filename=\"anh\"");
sb.AppendLine("Content-Type: image/jpg");
sb.AppendLine("");
StringBuilder sb1 = new StringBuilder();
sb1.AppendLine("");
sb1.AppendLine("--" + boundary + "--");
// Convert the StringBuilder into a string
data = Encoding.UTF8.GetBytes(sb.ToString());
data1 = Encoding.UTF8.GetBytes(sb1.ToString());
//
using (FileStream fs = new FileStream(#"D:\17. NHATLINH\ToolKit_Catchoom\ToolKit_Catchoom\bin\Debug\aa.jpg", FileMode.Open, FileAccess.Read))
{
length = data.Length + fs.Length + data1.Length;
// đưa thông tin chiều dài của gói gửi đi vào
request.ContentLength = length;
//
using (Stream stream = request.GetRequestStream())
{
// ghi header vào gói gửi đi
stream.Write(data, 0, data.Length);
//
buffer = new Byte[checked((uint)Math.Min(4096, (int)fs.Length))];
// buffer = new Byte[fs.Length];
// Write the file contents
while ((bytesRead = fs.Read(buffer, 0, buffer.Length)) != 0)
{
stream.Write(buffer, 0, bytesRead);
}
stream.Write(data1, 0, data1.Length);
//
try
{
Console.WriteLine(request.ContentType);
Console.WriteLine(sb.ToString() + sb1.ToString());
WebResponse responce = request.GetResponse();
Stream s = responce.GetResponseStream();
StreamReader sr = new StreamReader(s);
MessageBox.Show(sr.ReadToEnd());
}
catch (Exception ec)
{
MessageBox.Show(ec.Message);
}
}
}

Answer 1

Building a multipart-encoded request is an error-prone task ( it is normal if you feel frustrated trying ), I recommend you to use a library to handle this kind of things, no point in reinventing the wheel :)
If you are using the Microsoft .NET Framework >= 4.5, you may use the HttpClient class as this answer explains.
Hope this help you ;)