Question

I want to process a field retrieved from the database for a Gridview to check to see if the information in it is a hyperlink. If it is, I want to generate a link from it, otherwise just leave it as raw text. At the moment the field in the Gridview looks like:

    <asp:TemplateField HeaderText="Reference">
        <EditItemTemplate>
            <asp:TextBox ID="txtReference" runat="server" Text='<%# Bind("Reference") %>'></asp:TextBox>
        </EditItemTemplate>
        <ItemTemplate>
            <asp:Label ID="Label3" runat="server" Text='<%# Bind("Reference") %>'></asp:Label>
        </ItemTemplate>
    </asp:TemplateField>

I tried modifying what’s in the ‘Text’ attribute of the ItemTemplate but no matter what I put in I get errors on pageload. How can I dynamically modify what’s sent to the browser based on the specific info bound in this field?

Thanks a lot!

Answer 1

I fixed this by using both a Label and a HyperLink in my TemplateField, showing the HyperLink (and hiding the Label) if the bound text qualifies as a proper URL.

The following ASP.NET sets up the potential HTML to output:

ASP.NET

<asp:TemplateField HeaderText="Reference"> 
    <ItemTemplate>
                <asp:Label ID="lblReference" runat="server" Visible='<%# !isTextHyperlink(Eval("Reference")) %>' Text='<%# Bind("Reference") %>'/>
                <asp:HyperLink ID="hlReference" runat="server" Visible='<%# isTextHyperlink(Eval("Reference")) %>' Text='<%# Bind("Reference") %>' NavigateUrl='<%# Bind("Reference") %>'/>
    </ItemTemplate> 
</asp:TemplateField> 

I added a function in the pages ‘codebehind’ like this:

C#

protected bool isTextHyperlink(object refobj)
{
    string refstring = refobj.ToString();
    try
    {
        Uri uri = new Uri(refstring);
        return Uri.CheckSchemeName(uri.Scheme);
    }
    catch
    {
        // not a valid uri (that Uri can construct with)
        return false;
    }
}

Many thanks to Brissles for the suggestion.