Sometimes you need to check if the file exists before downloading it to your computer, you can follow this article.
Creating a simple windows forms application allows you to enter a url, then check if file exists on server in c# as shown below.

Creating a FileExists method, we will use HttpWebRequest to create a request to web server, then use HttpWebResponse to get respone return from web server.
private bool FileExists(string url)
{
try
{
HttpWebRequest request = WebRequest.Create(url) as HttpWebRequest;
request.Method = "HEAD";
using (HttpWebResponse response = request.GetResponse() as HttpWebResponse)
{
return (response.StatusCode == HttpStatusCode.OK);
}
}
catch
{
return false;
}
}
If your StatusCode response is OK, we will return true, otherwise false.
Adding a click event handler to the Check button allows you to check if file exists on Server in c#.
private void btnCheck_Click(object sender, EventArgs e)
{
bool result = FileExists(txtUrl.Text);
if (result)
MessageBox.Show("The file exists on the server.", "Message", MessageBoxButtons.OK, MessageBoxIcon.Information);
else
MessageBox.Show("The file couldn't be found on the server.", "Message", MessageBoxButtons.OK, MessageBoxIcon.Information);
}
if the resulting value equals false, your file doesn't exist on the server.