Windows Forms: How to Upload Image To Server in C#

Dragging PictureBox, Button, TextBox controls from the Visual Studio toolbox into your form designer, then design a simple UI allows you to display image to PictureBox, show image path to TextBox and upload image to server in c# as shown below.

How to call web api post method from windows application in c#

Right-clicking on your project, then select Manage Nuget Packages. Next, Search 'RestSharp', then download and install it.

You should create a web api allows you to upload file to web server. If you don't know how to create a web api you can view this post How to Upload files in ASP.NET Core Web API using C#.

Adding a click event handler to the Upload button allows you to upload an image to server in c#.

private async void btnUpload_Click(object sender, EventArgs e)
{
    //c# open file dialog with image filters
    using (OpenFileDialog ofd = new OpenFileDialog() { Filter = "Image Files(*.jpg; *.jpeg; *.gif; *.bmp; *.png)|*.jpg; *.jpeg; *.gif; *.bmp; *.png" })
    {
        if (ofd.ShowDialog() == DialogResult.OK)
        {
            //c# display image in picture box  
            pictureBox1.Image = new Bitmap(ofd.FileName);
            //c# show image file path  
            txtFileName.Text = ofd.FileName;
            //c# upload image to web server
            using (var fileStream = File.Open(ofd.FileName, FileMode.Open))
            {
                var client = new RestClient("http://localhost:11122/api/file/upload");
                var request = new RestRequest(Method.POST);
                using (MemoryStream memoryStream = new MemoryStream())
                {
                    await fileStream.CopyToAsync(memoryStream);
                    request.AddFile("file", memoryStream.ToArray(), ofd.FileName);
                    request.AlwaysMultipartFormData = true;
                    var response = await client.ExecuteAsync(request);
                    if (response.StatusCode == System.Net.HttpStatusCode.OK)
                    {
                        dynamic json = JsonConvert.DeserializeObject(response.Content);
                        string fileName = json.fileName;
                        //Handling your code
                    }
                }
            }
        }
    }
}

If you want to get the filename when the file is uploaded to the server. You need to install RestSharp.Newtonsoft.Json from Manage Nuget  Packages in your Visual Studio.

Through this post, i hope so you can understand how to upload image to server c# windows application via c# web api upload file with model asp.net core.