使用C#将文件上载到PHP WebServer

Recently i have coded a Simple File Upload Form in HTML and PHP Code:

<!DOCTYPE html>
    <html>
         <body>

         <form action="upload.php" method="post" enctype="multipart/form-data">Select image to upload:
         <input type="file" name="fileToUpload" id="fileToUpload">
         <input type="submit" value="Upload" id="submitbtn" name="submit">
   </form>
</body>
</html>

PHP Code :

<?php
$target_dir = "uploads/";
$target_file = $target_dir . basename($_FILES["fileToUpload"]["name"]);
$uploadOk = 1;
$imageFileType = pathinfo($target_file,PATHINFO_EXTENSION);

// Check if $uploadOk is set to 0 by an error
if ($uploadOk == 0) {
    echo "Sorry, your file was not uploaded.";
    // if everything is ok, try to upload file
} else {
    if (move_uploaded_file($_FILES["fileToUpload"]["tmp_name"], $target_file)) {
    echo "The file ". basename( $_FILES["fileToUpload"]["name"]). " has been uploaded.";
    } else {
    echo "Sorry, there was an error uploading your file.";
    }
} 
?>

Ok So i want to Upload The File On the webserver Using C# I tried "getElementById" but did'nt worked, the Problem is How can i Put File in FileName Property ?

Thanks Any Help appreciated.