Error creating control: ID property is not specified

A

Allan Ebdrup

I get the error "Error creating control: ID property is not specified" when
I view my custom web control in design view.
I add the control that gives an error in OnInit like this:
-----
foreach (WizardStep ws in WizardSteps)
{
CustomWizardStepHeader header = new CustomWizardStepHeader();
header.ID = "CustomWizardStepHeader";
ws.Controls.AddAt(0, header);
}
 
W

Walter Wang [MSFT]

Hi Allan,

Is your custom web control a User Control or a Server Control? I assume
you're creating a custom Server Control which inherits from the Wizard
control. When you use this customer Server Control on a Web Form, you will
also need to assign the ID property for it. For example:

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs"
Inherits="_Default" %>
<%@ Register TagPrefix="c" Namespace="myns" Assembly="__code" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>Untitled Page</title>
</head>
<body>
<form id="form1" runat="server">
<div>

<c:Class1 runat="server"></c:Class1>
</div>
</form>
</body>
</html>


Above code will report error "Error creating control ID property is not
specified" if you switch to the designer, you will need to change to:

<c:Class1 runat="server" ID="c1"></c:Class1>


I hope I haven't misunderstood anything, in that case, please post more
about your code. Thanks.


Regards,
Walter Wang ([email protected], remove 'online.')
Microsoft Online Community Support

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A

Allan Ebdrup

Walter Wang said:
Hi Allan,

Is your custom web control a User Control or a Server Control? I assume
you're creating a custom Server Control which inherits from the Wizard
control.
Click to expand...

Yes it's a server control.
When you use this customer Server Control on a Web Form, you will
also need to assign the ID property for it. For example:
Click to expand...
<snip>

There is an ID assigned to the tag, and everything runs fine when I run the
page, the problem only occurs in design view.
I've added IDs to all the controls that are generated programatically and
now I get a different error (again only in design view not when I run the
page)
On the Child Control I've added a "CustomWizard" property in whitch I set
the Wizard control that the Child is a Child of (the header knows what
wizard it's part of).
Now I get the following error in design view:

"Cannot create an object of type 'CustomWizard' from its string
representation 'CustomWizard1' for the CustomWizard Property."

I guess it's because of some kind of serialization or something so I've
added the following attributes to tha CustomWizard property in the child
control:

[System.ComponentModel.Browsable(false)]
[System.ComponentModel.EditorBrowsable(System.ComponentModel.EditorBrowsableState.Never)]
[System.ComponentModel.DesignerSerializationVisibility(System.ComponentModel.DesignerSerializationVisibility.Hidden)]

But that didn't solve the problem.

Can't you add properties to controls and only use them programatically? What
am I missing?

Kind Regards,
Allan Ebdrup
 
A

Allan Ebdrup

I've tried adding a typeconverter:
----------------
public class PageControlTypeConverter<TControl> : TypeConverter where
TControl : Control
{
// Overrides the CanConvertFrom method of TypeConverter.
// The ITypeDescriptorContext interface provides the context for the
// conversion. Typically, this interface is used at design time to
// provide information about the design-time container.
public override bool CanConvertFrom(ITypeDescriptorContext context,
Type sourceType)
{
if (sourceType == typeof(string))
{
return true;
}
return base.CanConvertFrom(context, sourceType);
}
// Overrides the ConvertFrom method of TypeConverter.
public override object ConvertFrom(ITypeDescriptorContext context,
CultureInfo culture, object value)
{
if (value is string)
{
Page page = (Page)HttpContext.Current.Handler;
TControl c = page.FindControl((string)value) as TControl;
return c;
}
return base.ConvertFrom(context, culture, value);
}
// Overrides the ConvertTo method of TypeConverter.
public override object ConvertTo(ITypeDescriptorContext context,
CultureInfo culture, object value, Type destinationType)
{
if (destinationType == typeof(string))
{
return ((TControl)value).ID;
}
return base.ConvertTo(context, culture, value, destinationType);
}
}
 
W

Walter Wang [MSFT]

Hi Allan,

I'm not sure if this is caused by the TypeConverter or not. I cannot tell
clearly what might be the cause without reproducing the issue on my side
and see the detailed error messages. Could you please create a reproducible
project and send it to me? Thank you for the trouble.


Regards,
Walter Wang ([email protected], remove 'online.')
Microsoft Online Community Support

==================================================
When responding to posts, please "Reply to Group" via your newsreader so
that others may learn and benefit from your issue.
==================================================

This posting is provided "AS IS" with no warranties, and confers no rights.
 

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