Passing a query string value retrieved to an ImageUrl attribute of an image control using asp.net c#

You should be using an ImageButton instead of an image and wiring to the Click event.  The ImageUrl property just tells the server where to find the image to display.

In your markup:
<asp:ImageButton ID="imageButton1" runat="server" ImageUrl="myImage.gif" OnClick="imageButton1_Click" />
 
In your codebehind:
 
protected void imageButton1_Click(object sender, ImageClickEventArgs e)
{
    string ddum = "1";
    string url = string.Format("="~/RetrieveImage.aspx?ID={0}", ddum);
 
    Response.Redirect(url);
}

                                              

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Thanks Nash2334. Looks like you are very close. I will explain my situation. I have a gridview which has a column as hyperlink. when you click on a link  it will grab corresponding information on the row and pass it as a querystring to the next page "displayimage.aspx".
In dislayimage.aspx, I already have 3 values from the querystring which I am displaying as labels. I now want it to fetch a picture from another page (4th value)  while the display.aspx loads.
There will be no button to click so I cannot use an image button. the picture should be loaded when the displayimage pages loads.

I hope this is clear.

Thanks.

How does RetrieveImage.aspx retrieve the image?  As a binary?  Does it simply embed it in its own markup?

You've got two options here:

1. Put RetrieveImage.aspx with an asp:Image in an iframe in your displayimage.aspx, then load the ImageUrl in the Page_Load of RetrieveImage.aspx.
2. Ditch RetrieveImage.aspx altogether and process the image retrieval in displayimage.aspx itself.

I'm not sure what purpose RetrieveImage.aspx is playing here, and why whatever logic it is processing can't be put directly into displayimage.aspx.

In summary Nash2334, I want to be able to fire that Imagebutton click event within the page load without anyone clicking on anything.

The RetrieveImage.aspx  is returning a byte image which has to run by it self and I am now returning this object to the image container to store it for me.

OK, but if it is returning a byte image why is it part of an ASPX page?  Shouldn't this be a separate method in a class file?  Why bind it to markup that is never used?

Thanks. This is the way the image is been returned.

byte[] Imageset = oDoc.GetPhoto(person.Id, sStudentPhotoDocType);
               if (Imageset != null)
               {
                   Response.Buffer = true;
                   Response.ContentType = "Image/JPEG";
                   Response.BinaryWrite(Imageset);
               }
    I wasnt sure you could use Response in a class library.  Are you suggesting I put this in a class library and now return this to the image control

Yes, there is no reason to have this in an ASPX.  You could create a Utility class instead, then call the method in the Utility class to load the image directly in the Page_Load of DisplayImage.aspx.  You won't need RetrieveImage.aspx at all using this method.

thanks again for your response Nash2334. I just tried doing this using a class library and I received errors with  response.buffer etc. There is no response in the intellisence.

How can i deal with this?

byte[] Imageset = oDoc.GetPhoto(person.Id, sStudentPhotoDocType);
               if (Imageset != null)
               {
                   Response.Buffer = true;
                   Response.ContentType = "Image/JPEG";
                   Response.BinaryWrite(Imageset);
               }

What is the exact error?  You need to post more of your code.  The snippet you provide is fine.