How can I check if an Image exists at http://someurl/myimage.jpg in C#/ASP.NET It seems like there ought to be a method to check for this -- but I cannot find one.
I found this , but it doesn't really answer the question.
This code should work:
private static bool UrlExists(string url)
{
try
{
new System.Net.WebClient().DownloadData(url);
return true;
}
catch (System.Net.WebException e)
{
if (((System.Net.HttpWebResponse)e.Response).StatusCode == System.Net.HttpStatusCode.NotFound)
return false;
else
throw;
}
}
您可以尝试使用System.Net.WebRequest
向该URL发送“HEAD”请求并检查响应以查看该文件是否存在 - 这应该可以完成工作,而无需尝试下载它。
string fileextension = Path.GetExtension(filename);
if (fileextension.ToLower() == ".png" || fileextension.ToLower() == ".jpg" || fileextension.ToLower() == ".jpeg" || fileextension.ToLower() == ".gif" || fileextension.ToLower() == ".bmp"){}
You could use a System.Net.WebClient.DownloadFile function to try to load the image from the URL and see if you get an error. (Most likely a 404 Not Found error)
Its about the only way to do it from a URL. The System.IO namespace and all the functions in there are intended for files on a local machine or a network, so they would be useless to you in this situation.
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