CODEWITHSUNDEEP
c#restasp.net-web-api.net-core
user1436795
user1436795

Reputation: 49

How to upload a photo from winform application via API?

I have two projects. One is a Windows Form project, the other one is a .NET Core 2.0 Web API project. I can call my Web API from the Windows Form application and I can make call basic CRUD operations.

I need to POST a photo. How do I do that? My POST looks like that:

private async void AddStudent()
{
    var p = new Student
    {
        FirstName = "Johdn",
        LastName = "Doe",
        Avatar = "Image"; // my photo
    };

    using (var client = new HttpClient())
    {
        var serializedStudent = JsonConvert.SerializeObject(p);
        var content = new StringContent(serializedStudent, Encoding.UTF8, "application/json");
        var result = await client.PostAsync(URI, content);
    }
}

The Web API implementation looks like this:

public void Post([FromBody] Student student)
{
    var insideStudent = _dbContext.Students.FirstOrDefault(cus => cus.Id == student.Id);
    if (insideStudent != null)
    {
        insideStudent.FirstName = student.FirstName;
        insideStudent.LastName = student.LastName;
        _dbContext.SaveChanges();
    } else {
        _dbContext.Students.Add(new Student
        {
            FirstName = student.FirstName,
            LastName = student.LastName,
            Avatar = student.Avatar // my photo
        });
        _dbContext.SaveChanges();
    }
}

But how can I send an image to my Web API?

Upvotes: 1

Views: 1619

Answers (1)

Bob Dust
Bob Dust

Reputation: 2460

MultipartFormDataContent can be an option. Given that Student.Avatar is a byte array:

public byte[] Avatar { get; set; }

and you have the stream of the image, you can send it as byte array content along with string content:

    private async void AddStudent()
    {
        var stream = //gets image stream...
        var p = new Student
        {
            FirstName = "Johdn",
            LastName = "Doe",
        };
        using (var client = new HttpClient())
        {
            var serializedStudent = JsonConvert.SerializeObject(p);
            var stringContent = new StringContent(serializedStudent, Encoding.UTF8, "application/json");
            var multipartContent = new MultipartFormDataContent();
            using (var mem = new MemoryStream())
            {
                await stream.CopyToAsync(mem);
                var byteContent = new ByteArrayContent(mem.ToArray());
                multipartContent.Add(byteContent, "files", "my file");
                multipartContent.Add(new StringContent(p.FirstName), "FirstName");
                multipartContent.Add(new StringContent(p.LastName), "LastName");
                var response = await client.PostAsync(URI, multipartContent);
            }
        }
    }

then you can receive those on server-side:

    [HttpPost]
    public async void Post([FromForm]Student student)
    {
        var form = Request.Form;
        var insideStudent = _dbContext.Students.FirstOrDefault(cus => cus.Id == student.Id);
        if (insideStudent != null)
        {
            insideStudent.FirstName = student.FirstName;
            insideStudent.LastName = student.LastName;
            _dbContext.SaveChanges();
        }
        else
        {
            var newStudent = new Student
            {
                FirstName = student.FirstName,
                LastName = student.LastName
            };
            if(form.Files.Any())
            {
                using (var stream = new MemoryStream())
                {
                    await form.Files[0].CopyToAsync(stream);
                    newStudent.Avatar = stream.ToArray();
                }
            }
            _dbContext.Students.Add(newStudent);
            _dbContext.SaveChanges();
        }
    }

Upvotes: 1

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