SSRS 2008 R2 检查报表服务器上是否存在外部图像

我正在处理 SSRS 2008 R2 报告，并且正在动态显示图像.如果图像在我们的报表服务器上不存在，我想隐藏图像框并显示一个带有文本的图标，上面写着找不到图像".

I'm working on an SSRS 2008 R2 report and I'm displaying images dynamically. I would like to hide the image box and display an icon with text that reads "Image not found" if the image doesn't exist on our report server.

我已经尝试了一些关于表达式的方法，但我无法根据图像是否存在让它们正确返回 true 或 false.

I've tried a few things with expressions, but I can't get them to correctly return true or false, based on if the image exists or not.

我用来显示图像的表达式是:

The expression I'm using to display the image is:

="/BusinessIntelligence/Drilldown Reports/" + Fields!item.Value + ".jpg"

为了测试我是否可以让报告检测图像是否存在，我将一个文本框拖到我的报告上并尝试了以下表达式以尝试返回 True 或 False代码>.

To test if I could get the report to detect whether the image existed, I dragged a textbox onto my report and tried the following expressions in an attempt to return True or False.

=IIf(IsNothing("/BusinessIntelligence/Drilldown Reports/" + Fields!item.Value + ".jpg"), "Woohoo!", "Do'h!") 这总是返回 False，即使图像存在.

=IIf(IsNothing("/BusinessIntelligence/Drilldown Reports/" + Fields!item.Value + ".jpg"), "Woohoo!", "Do'h!") this always returns False, even if the image exists.

我什至尝试使用我发现的一些自定义代码 这里.

I even tried using some custom code I found here.

代码:

Function IsValid(ByVal Url As String) As Boolean 
Dim sStream As IO.Stream 
Dim URLReq As Net.HttpWebRequest 
Dim URLRes As Net.HttpWebResponse 
Try 
URLReq = Net.WebRequest.Create(Url) 
URLReq.Credentials = System.Net.CredentialCache.DefaultCredentials 
URLRes = URLReq.GetResponse() 
sStream = URLRes.GetResponseStream() 
Dim reader As String = New IO.StreamReader(sStream).ReadToEnd() 
Return True 
Catch ex As Exception 
Return False 
End Try 
End Function

我用于该代码的表达式是:

And the expression I used for that code is:

=IIf(Code.IsValid("/BusinessIntelligence/Drilldown Reports/" + Fields!item.Value + ".jpg"), "Woohoo!", "Do'h!")

但这也总是只返回 false.

But this also always just returns false.