Consume Web API In Winform For File Handling

WEB API getFileInfo Method

Using this get method, we return all the file information as a JSON result.

//api/ FileHandlingAPI/getFileInfo?Id=1  
[ActionName("get"), HttpGet]  
public IEnumerable<FilePath> getFileInfo(int Id)  
{  
    List<FilePath> files = new List<FilePath>();  
    var uploadPath = HttpContext.Current.Server.MapPath("~/Uploads");  

    DirectoryInfo dirInfo = new DirectoryInfo(uploadPath);  

    foreach (FileInfo fInfo in dirInfo.GetFiles())  
    {  
        files.Add(new FilePath() { Path = uploadPath, Filename = fInfo.Name, Length = fInfo.Length, IsDirectory = File.GetAttributes(uploadPath).HasFlag(FileAttributes.Directory) });  
    }  
    getAllSubfolderFiles(dirInfo, files);  
    return files.ToList();  
}

When we run the Web API application, we can see the file details in JSON, as shown below.

Our Web API part is complete. Now, we can create a Winform application to consume the Web API and upload/download the files from web server to our local machine.

Step 4 Create Winform application

Open Visual Studio 2015. Click New >> Project >> Visual C# >> Windows >> select Windows Forms Application. Enter your project name and click OK.

Step 5 Install Packages

Install Microsoft.AspNet.WebApi.Client and Newtonsoft.json using NuGet Package Manager.

Right click the solution and click on "Manage NuGet Packages" and install the above two files.

Step 6 Design the Windows form like below

Add 3 buttons - one for File Browsing and uploading to the web server, second one for downloading the file from web server, and a third one to get File List to collect all the file information from webserver and binding it to grid.

Browse/Upload File Button Click

In upload file button click, we call the method as upload and pass the Web API URL to upload the file to the web server file path.

#region Upload File  
//Upload File Button Click event  
private void btnUpload_Click(object sender, EventArgs e)  
{  

     Boolean uploadStatus = false;  
    DialogResult dr = this.openFileDialog1.ShowDialog();  
    if (dr == System.Windows.Forms.DialogResult.OK)  
    {  
        foreach (String localFilename in openFileDialog1.FileNames)  
        {  
            string url = "http://localhost:51389/api/FileHandlingAPI";  
            string filePath = @"\";  
            Random rnd = new Random();  
            string uploadFileName = "Imag"+rnd.Next(9999).ToString();  
            uploadStatus = Upload(url, filePath, localFilename, uploadFileName);  
        }  
    }  
    if (uploadStatus)  
    {  
        MessageBox.Show("File Uploaded");  
    }  
    else  
    {  
        MessageBox.Show("File Not Uploaded");  
    }  
}  
// filepath = @"Some\Folder\";  
// url= "http://localhost:51389/api/FileHandlingAPI";  
// localFilename = "c:\newProduct.jpg"   
//uploadFileName="newFileName"  
bool Upload(string url, string filePath, string localFilename, string uploadFileName)  
{  
    Boolean isFileUploaded = false;  

    try  
    {  
        HttpClient httpClient = new HttpClient();  

        var fileStream = File.Open(localFilename, FileMode.Open);  
        var fileInfo = new FileInfo(localFilename);  
        UploadFIle uploadResult = null;  
        bool _fileUploaded = false;  

        MultipartFormDataContent content = new MultipartFormDataContent();  
        content.Headers.Add("filePath", filePath);  
        content.Add(new StreamContent(fileStream), "\"file\"", string.Format("\"{0}\"", uploadFileName  + fileInfo.Extension)  
                );  

        Task taskUpload = httpClient.PostAsync(url, content).ContinueWith(task =>  
        {  
            if (task.Status == TaskStatus.RanToCompletion)  
            {  
                var response = task.Result;  

                if (response.IsSuccessStatusCode)  
                {  
                    uploadResult = response.Content.ReadAsAsync<UploadFIle>().Result;  
                    if (uploadResult != null)  
                        _fileUploaded = true;  
                }
            }  
            fileStream.Dispose();  
        });  

        taskUpload.Wait();  
        if (_fileUploaded)  
            isFileUploaded = true;
        httpClient.Dispose();  

    }  
    catch (Exception ex)  
    {  
        isFileUploaded = false;  
    }  
    return isFileUploaded;  
}  

#endregion

Get File List Button Click

In GetFileInformation method, we pass the Web API URL to get all the file details from web server. From Web API, we get the file information as JSON result. In the Winform application, we have used Jsonconvert to deserialize and bind the result to the DataGridView.

#region FileInformation  
//Get File List  
private void btnFileList_Click(object sender, EventArgs e)  
{  
    string URI = "http://localhost:51389/api/FileHandlingAPI/getFileInfo?Id=1";  
    GetFileInformation(URI);  
}  

   
private async void GetFileInformation(string url)  
{  
    List<ServerFileInformation> filesinformation = new List<ServerFileInformation>();  
    using (var client = new HttpClient())  
    {  
        using (var response = await client.GetAsync(url))  
        {  
            if (response.IsSuccessStatusCode)  
            {  
                var fileJsonString = await response.Content.ReadAsStringAsync();  

             dataGridView1.DataSource = JsonConvert.DeserializeObject<ServerFileInformation[]>(fileJsonString).ToList();   
            }  
        }  
    }  
}  
#endregion

Download Button Click

In Download method, we pass the Web API URL with file name to download, and local computer save location. Here, we have used the Winfrom root folder to save the file from web server to our local machine.

#region Download File  
//Download File  
private void btnDownload_Click(object sender, EventArgs e)  
{  
    string url = "http://localhost:51389/Uploads/";  
    string downloadFileName = txtFileName.Text.Trim();  
    string downloadPath = Application.StartupPath + @"\Downloads\";  

    if (!Directory.Exists(downloadPath))  
        Directory.CreateDirectory(downloadPath);  

    Boolean isFileDownloaded = Download(url, downloadFileName, downloadPath);  
    if (isFileDownloaded)  
    {  
        MessageBox.Show("File Downloaded");  
    }  
    else  
    {  
        MessageBox.Show("File Not Downloaded");  
    }  
}  

// url = http://localhost:51389/Uploads/"    
// downloadFileName = "new2.jpg"   
// downloadPath =  Application.StartupPath + "/Downloads/";  
bool Download(string url, string downloadFileName, string downloadFilePath)  
{  
    string downloadfile = downloadFilePath + downloadFileName;  
    string httpPathWebResource = null;  
    Boolean ifFileDownoadedchk = false;  
    ifFileDownoadedchk = false;  
    WebClient myWebClient = new WebClient();  
    httpPathWebResource = url + downloadFileName;  
    myWebClient.DownloadFile(httpPathWebResource, downloadfile);  

    ifFileDownoadedchk = true;  

    return ifFileDownoadedchk;  
}

Reference Link

https://chsakell.com/2015/06/07/web-api-file-uploading-desktop-and-web-client/

Conclusion

Build and run the application. Publish the Web API to your web server and update the Web API URL in the Winform. You can test your application now. From the attached zipped file, you can download both, Winform and Web API, source files.