Designer Support for Selecting Web Form control

[Paul Ingles]

I've got a validator control that has somewhat limited designer support. It
has an additional property that contains a string identifying another
control on the form, e.g. "MyListBox".

The BaseValidator control has a ControlToValidate property that does exactly
what I need it to for this property, but was wondering how it actually
works?

I'd like it so that the VS.NET designer displays a drop-down list of all
controls on the web form that are of type MyListBoxControl, so the developer
can just select it and hey presto.

Is this done using a custom designer, a custom type editor?

Thanks for all suggestions,
Paul

 

[Victor Garcia Aprea [MVP]]

Hi Paul,

You need a custom type converter. The BaseValidator.ControlToValidate
property has a type converter of type
System.Web.UI.WebControls.ValidatedControlConverter. This custom type
converter does examine every control looking if they have the
ValidationPropertyAttribute applied.

--
Victor Garcia Aprea
Microsoft MVP | ASP.NET
Looking for insights on ASP.NET? Read my blog:
http://obies.com/vga/blog.aspx
To contact me remove 'NOSPAM'. Please post all questions to the newsgroup
and not by private mail.

 

[Teemu Keiski]

I'd like to follow up Victor's post so that here is an example how such
converter is done from scratch to pick up all DataGrids on the Page.

http://www.asp.net/Forums/ShowPost.aspx?tabindex=1&PostID=212648

Thanks,

--
Teemu Keiski
MCP, Designer/Developer
Mansoft tietotekniikka Oy
http://www.mansoft.fi

AspInsiders Member, www.aspinsiders.com
ASP.NET Forums Moderator, www.asp.net
AspAlliance Columnist, www.aspalliance.com

 

[Paul Ingles]

Thanks very much for the link.

I'd like to follow up Victor's post so that here is an example how such
converter is done from scratch to pick up all DataGrids on the Page.

http://www.asp.net/Forums/ShowPost.aspx?tabindex=1&PostID=212648

Thanks,

--
Teemu Keiski
MCP, Designer/Developer
Mansoft tietotekniikka Oy
http://www.mansoft.fi

AspInsiders Member, www.aspinsiders.com
ASP.NET Forums Moderator, www.asp.net
AspAlliance Columnist, www.aspalliance.com

 

[John Saunders]

I looked at the examples on ASP.NET, and have a suggestion. I similarly have
a control which has a property which needs to be the ID of one of the other
controls on the page. I used a TypeConverter derived from StringConverter to
do this.

However, instead of searching context.Container.Components, I used the
IReferenceService. Here's the code in C#:

public override TypeConverter.StandardValuesCollection
GetStandardValues(ITypeDescriptorContext context)
{
IReferenceService service = (IReferenceService)
context.GetService(typeof(IReferenceService));
object[] references = service.GetReferences(typeof(Control));
TypeConverter.StandardValuesCollection coll = new
TypeConverter.StandardValuesCollection(references);
return coll;
}

The following is an attempt to translate that into VB, but I won't have
tested it:

Public Overrides Function GetStandardValues(context as
ITypeDescriptorContext) as TypeConverter.StandardValuesCollection
Dim service as IReferenceService =
CType(context.GetService(GetType(IReferenceService)), IReferenceService)
Dim references() as Object = service.GetReferences(GetType(Control))
Dim coll as New TypeConverter.StandardValuesCollection(references)
Return coll
End Function

John Saunders
(e-mail address removed)