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check if image exists

Posted on 2007-11-22
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Last Modified: 2013-12-16
In ASP.NET 2.0 with C# I have a page with an <asp:Image> control.
I have the img.ImageUrl that contain the link for the image.
I want to make a check if the image exists. How do I do this check?
thankyou
Anat
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Question by:ANAT2403
7 Comments
 
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Expert Comment

by:joex911
ID: 20335088
Hi, this is one way of doing it:
// for relative URL
bool imgFound = System.IO.File.Exists(Server.MapPath(img.ImageUrl));
 
// for absolute URL
bool imgFound = System.IO.File.Exists(img.ImageUrl);

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Expert Comment

by:cmhunty
ID: 20335119
If the URL is not local, you can use something like this (sorry, it's in VB.NET but may give you an idea):

    Private Function ImageExists(ByVal strURL As String) As Boolean
        Dim blExists As Boolean = True
        Try
            Dim req As HttpWebRequest = WebRequest.Create(strURL)
            Dim res As HttpWebResponse = req.GetResponse
        Catch ex As Exception
            blExists = False
        End Try
        Return blExists
    End Function
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Author Comment

by:ANAT2403
ID: 20335211
Hi joex911
this is my imgurl:
http://192.168.1.101/appsrv/vg_paint?s=main&w=110&bg=bg1&h=80&q=100&f=models/79942.jpg
this return an image
and this does not return anything:
http://192.168.1.101/appsrv/vg_paint?s=main&w=110&bg=bg1&h=80&q=100&f=models/5.jpg
your first suggestion for relative URL returned an error on both cases and you second returned false for both cases. Do you have another suggestion?
Hi cmhunty
I could not define HttpWebRequest . What using do I need for this?
Thankyou
Anat

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Expert Comment

by:cmhunty
ID: 20335389
Use System.Net. With my limited knowledge of C#, I tried to recreate but struggled. Maybe someone else could convert?
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Accepted Solution

by:
joex911 earned 250 total points
ID: 20335466
With the method's I put up the image has to be local on the server. I can convert cmhunty code to c# though
private bool ImageExists(string strURL)
{
  bool blExists = true
  try
  {
    System.Net.HttpWebRequest req = System.Net.WebRequest.Create(strURL);
    System.Net.HttpWebResponse res = req.GetResponse();
  }
  Catch(Exception ex)
  {
    blExists = false;
  }
  return blExists;
}

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Assisted Solution

by:cmhunty
cmhunty earned 250 total points
ID: 20335512
Managed to convert to C# - seems you can't convert HttpWebRequest to WebRequest in C# but can in VB.NET

private bool ImageExists(string strURL)
{
  bool blExists = true;
  try
  {
      WebRequest req = WebRequest.Create(strURL);
      WebResponse res = req.GetResponse();

  }
  catch(Exception ex)
  {
    blExists = false;
  }
  return blExists;
}
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Expert Comment

by:Göran Andersson
ID: 20335663
VB.NET allows an implicit conversion, but only if you don't use Option Strict.

In C# you always have to do an explicit cast if the compiler can't tell that the cast is safe:

HttpWebRequest req = (HttpWebRequest)WebRequest.Create(strURL);
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