Hide image control if no image

Question

User1510859543 posted

I would like to hide an html file element and asp.net image control when no image is found.  I have the following markup inside the ItemTemplate of a ListView control.

<asp:Image ID="imgPartPhoto" runat="server" Width="100" onclick="showbig(this);" />
<input type="file" id='<%# Eval("InventoryID") %>' />

In the ItemDatabound event in my code behind I am using the following code to populate images on each row.  I want to be able to hide both controls when an image does not exists. I tried using File.Exists but that did not work.

        If e.Item.FindControl("imgPartPhoto") IsNot Nothing Then
            Dim lbl As Label
            Dim img As Image = e.Item.FindControl("imgPartPhoto")
            Dim strurl As String = ConfigurationManager.AppSettings("appurl")
            Dim strurlPhy As String = Server.MapPath("~/Photos/_Parts/") & rowView("InventoryID") & ".jpg"
            strurl = "../Photos/_Parts/" & rowView("InventoryID") & ".jpg"
            img.ImageUrl = strurl

        End If

Answer 1

User475983607 posted

In the ItemDatabound event in my code behind I am using the following code to populate images on each row.  I want to be able to hide both controls when an image does not exists. I tried using File.Exists but that did not work.

Where is the Exists code?

img.Visible = File.Exists(strurlPhy)

Are you sure ../Photos is correct?  This code find a file relative to the root.

Dim strurlPhy As String = Server.MapPath("~/Photos/_Parts/") & rowView("InventoryID") & ".jpg"

This code assumes the path is one level up.

strurl = "../Photos/_Parts/" & rowView("InventoryID") & ".jpg"

There is no guarantee both are correct.  Perhaps run your code through the visual studio debugger.

Answer 2

User-943250815 posted

You ca set control property Visible = False. but have to check if file exist on physical path

Dim img as Image = e.FindControl("imgPartPhoto")
Dim RootDir as string = HttpRuntime.AppDomainAppPath 
Dim ImgDir as string = IO.Path.GetFullPath(RootDir& <path from root dir>)
Dim ImgFileFull as string = ImgDir & "\" & <image file name with extension>
Dim FileExists as boolean = File.Exists(ImgFileFull)
if FileExists then
 img.Visible = True
else
img.Visible = false
endif

Answer 3

User61956409 posted

Hi dlchase,

I would like to hide an html file element and asp.net image control when no image is found. 

You can also achieve the requirement on client side by executing a JavaScript if an error occurs when loading an image, like below.

<asp:Image ID="imgPartPhoto" runat="server" Width="100" onerror="hideimg_Func(this)" onclick="showbig(this);" />
<input type="file" id='<%# Eval("InventoryID") %>' />

<script>
    function hideimg_Func(imgtag) {
        $(imgtag).hide();

        $(imgtag).next("input[type='file']").hide();
    }
</script>

With Regards,

Fei Han