How to check if file exists on Server in C#
By FoxLearn 7/18/2024 7:55:09 AM 3.94K
How to check if file exists on Web Server in C#
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) { string url = txtUrl.Text.Trim(); if (!Uri.IsWellFormedUriString(url, UriKind.Absolute)) { MessageBox.Show("Invalid URL format"); return; } bool result = FileExists(url); if (result) MessageBox.Show("The file exists on the web server.", "Message", MessageBoxButtons.OK, MessageBoxIcon.Information); else MessageBox.Show("The file couldn't be found on the web server.", "Message", MessageBoxButtons.OK, MessageBoxIcon.Information); }
If the resulting value equals false, your file doesn't exist on the server.
You can also use the HttpClient
class to send a HEAD request to the URL of the file.
private async Task<bool> CheckFileExistsAsync(string url) { using (HttpClient client = new HttpClient()) { var response = await client.SendAsync(new HttpRequestMessage(HttpMethod.Head, url)); return response.IsSuccessStatusCode; } }
The modify the click event handler as shown below.
private async void btnCheck_Click(object sender, EventArgs e) { string url = txtUrl.Text.Trim(); if (!Uri.IsWellFormedUriString(url, UriKind.Absolute)) { MessageBox.Show("Invalid URL format"); return; } bool result = await CheckFileExistsAsync(url); if (result) MessageBox.Show("The file exists on the web server.", "Message", MessageBoxButtons.OK, MessageBoxIcon.Information); else MessageBox.Show("The file couldn't be found on the web server.", "Message", MessageBoxButtons.OK, MessageBoxIcon.Information); }
In this example, there's a Windows Forms application with a text box for entering the URL and a button to check if the file exists. When the button is clicked, it checks if the URL is well-formed and then calls the CheckFileExistsAsync
method, which sends a HEAD request to the URL. If the response status code is 200 (OK), it means the file exists, otherwise, it doesn't.
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