ASP.NET is not calling C# code

Question

For some reason this following ASP code is not calling the c# method "checkLastNames" that is suppose to be evaluated in the 'Visible=' field below.

<asp:Button ID="btnZ" 
            runat="server" 
            Text="Z" 
            Height="20px" 
            Width="25px" 
            Font-Size="12px" 
            CommandArgument="Z" 
            OnClick="btnA_Click" 
            Visible='<%# checkLastNames("Z") %>' />

When I enter debug mode the method isn't even being called. Visible just defaults to true. I've tried changing the method to return only false just to see if it would work but "Visible" is still defaulting to true.

protected bool checkLastNames(string s){
    return false;
}

You're using the <%# format.. it should be <%= blah %>. # is for databinding. — adaam
– adaam, Commented Feb 10, 2014 at 16:43
That's the databinding syntax...are you calling DataBind() in the codebehind? — David W
– David W, Commented Feb 10, 2014 at 16:43
No, it's not databound, so that part of the problem. When I try with <%= %> I get an error : Cannot create an object of type 'System.Boolean' from its string representation '<%= checkLastNames("Z") %>' for the 'Visible' property. — Brian Kraemer
– Brian Kraemer, Commented Feb 10, 2014 at 16:56
Why not do this in the codebehind? It's much cleaner: btnZ.Visible = checkLastNames("Z"); — DGibbs
– DGibbs, Commented Feb 10, 2014 at 16:58
Yes, you're right. It is cleaner. I'm doing that now. Thank you! — Brian Kraemer
– Brian Kraemer, Commented Feb 10, 2014 at 17:05

Thomas Taylor · Accepted Answer · 2014-02-10 16:49:45Z

1

<asp:Button ID="btnZ" 
        runat="server" 
        Text="Z" 
        Height="20px" 
        Width="25px" 
        Font-Size="12px" 
        CommandArgument="Z" 
        OnClick="btnA_Click" 
        Visible='<%# checkLastNames("Z") %>' />

That # means it's only evaulated during a databind operation. So if you are not databinding the page explicitly (through calling DataBind()) then this won't show.

        Visible='<%= checkLastNames("Z") %>' />

You might want to try the code above. Also I would probably put this in a static function (assuming it's functionality is encapsulated in there)

answered Feb 10, 2014 at 16:49

Thomas Taylor

5654 silver badges13 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Tim Schmelter · Accepted Answer · 2014-02-10 16:48:37Z

0

<%# is for databinding expressions, so this works only if the namingcontainer control of this Button is databound.

For example in Page_Load:

this.DataBind();

But why not using codebehind in the first place?

btnZ.Visible = checkLastNames("Z");

answered Feb 10, 2014 at 16:48

Tim Schmelter

462k79 gold badges719 silver badges980 bronze badges

1 Comment

Brian Kraemer Over a year ago

Thanks. I'm getting an error when I change the code (Cannot create an object of type 'System.Boolean' from its string representation '<%= checkLastNames("Z") %>' for the 'Visible' property.) In any case, I'll just do it in code behind. Thank you.

Vignesh Kumar A · Accepted Answer · 2014-02-10 16:47:13Z

0

Try like this

<asp:Button ID="btnZ" 
            runat="server" 
            Text="Z" 
            Height="20px" 
            Width="25px" 
            Font-Size="12px" 
            CommandArgument="Z" 
            OnClick="btnA_Click" 
            Visible='<%= checkLastNames("Z") %>' />

answered Feb 10, 2014 at 16:47

Vignesh Kumar A

28.6k14 gold badges67 silver badges119 bronze badges

Collectives™ on Stack Overflow

ASP.NET is not calling C# code

3 Answers 3

Comments

1 Comment

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Related