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Tech Off - ASP.Net User control with codebehind not working

qwert231 — Tue, 23 Nov 2004 22:08:13 GMT

I have several pages that use the same collection of controls, an Img, and a couple of labels. I figured I could write a Usercontrol that would wrap everything up. I also wanted to programmatically read properties of this control to tell me whether the image was horizontal (width>height) or vertical (square counts as vertical).

So I lay my controls into the ASCX file, and then go into the codebehind create some public (readonly properties). No compile errors.
In my ascx file at the top I put this:
<%@ Control Inherits="uCtrlPreview" src="uCtrlPreview.vb" %>

I go into my first page (page1.aspx), give it a register tag, go down, put in my usercontrol tag. So far so good.
<%@ Register TagPrefix="UserControl" TagName="PrevImg" Src="previewImg.ascx"
%>
...

...
USERCONTROL:PrevImg id="Preview1" runat="Server">

I go into my page's (page1.aspx) codebehind and put this line:
Protected WithEvents Preview1 As uCtrlPreview

I get this message:
The base class includes the field 'Preview1', but its type
(ICUser.uCtrlPreview) is not compatible with the type of control
(ASP.previewImg_ascx).

Any ideas?

Tech Off - ASP.Net User control with codebehind not working

Knute — Tue, 23 Nov 2004 22:42:10 GMT

I had the same problem today, but it is in C#.

all you need to do is declare the control with it's name instead of declaring it as a user control. For instance, in my case:

public class sniff : System.Web.UI.UserControl {

code here

}

is then instantiated on my page thus:

protected sniff ctrl_Sniff;

I had tried to do it this way unsuccessfully:

protected System.Web.UI.UserControl ctrl_Sniff;

HTH,

~ Knute

Tech Off - ASP.Net User control with codebehind not working

qwert231 — Wed, 24 Nov 2004 14:13:21 GMT

Nah, that's how I was instantiating it, as a new sniff.

Now, in the ASP.net book i have they say to put a ClassName="" attribute in the ascx tag, like such:

<%@ Control Inherits="uCtrlPreview" src="uCtrlPreview.vb" ClassName="SomeOtherName" %>

saying that it is needed in case we dynamically create the control on a page.