R – Nothing from Property TagKey()

asp.netcustom-controls

I'm writing an ASP.NET custom composite control (Inherits System.Web.UI.WebControls.CompositeControl).

By default my control mark up renders surrounded by tags. I know I can over ride the property TagKey to set the return as whatever tag I want from the System.Web.UI.HtmlTextWriterTag enum.

My question: Can I make my control render without .NET adding markup around it?

UPDATE (3/2/2011) Thanks Swati for your answer. I want to show how I am solving my question now. I think I will integrate some of Swati's ideas. Specifically, AddAttributestoRender(), but I'm wondering if that is needed since the CompositeControl will lack a parent markup tag to hold the attributes.

When I don't want a containing markup tag, then I override one property & two methods from CompositeControl.

Protected Overrides ReadOnly Property TagKey() As System.Web.UI.HtmlTextWriterTag
    Get
        ' System defaults return as HtmlTextWriterTag.Span
        Return HtmlTextWriterTag.Unknown
    End Get
End Property

Public Overrides Sub RenderBeginTag(ByVal writer As System.Web.UI.HtmlTextWriter)
    If Me.TagKey <> HtmlTextWriterTag.Unknown Then
        MyBase.RenderBeginTag(writer)
    End If
End Sub

Public Overrides Sub RenderEndTag(ByVal writer As System.Web.UI.HtmlTextWriter)
    If Me.TagKey <> HtmlTextWriterTag.Unknown Then
        MyBase.RenderBeginTag(writer)
    End If
End Sub

Best Answer

Its possible to get rid of the containing tag with a CompositeControl, but its working against the way CompositeControl likes to work (see below)

The proper way, apparently, to set TagKey to whatever the main tag of your control actually is (a div, table, or whatever).

Then override AddAttributesToRender() to set the attributes you want on your wrapper tag.

The stuff you want inside the wrapping tags should be rendered by overriding the RenderContents() method.

CompositeControl inherits from WebControl, see a discussion of the user of TagKey and AddAttributesToRender() here.

Someone on GeeksWithBlogs writes about a similar issue here

To just get rid of the wrapping though, see this forum post that shows a way to override the control constructor and the RenderBeginTag and RenderEndTag methods to remove the wrapping tags.

Related Solutions

Asp.net-mvc – A potentially dangerous Request.Form value was detected from the client

I think you are attacking it from the wrong angle by trying to encode all posted data.

Note that a "<" could also come from other outside sources, like a database field, a configuration, a file, a feed and so on.

Furthermore, "<" is not inherently dangerous. It's only dangerous in a specific context: when writing strings that haven't been encoded to HTML output (because of XSS).

In other contexts different sub-strings are dangerous, for example, if you write an user-provided URL into a link, the sub-string "javascript:" may be dangerous. The single quote character on the other hand is dangerous when interpolating strings in SQL queries, but perfectly safe if it is a part of a name submitted from a form or read from a database field.

The bottom line is: you can't filter random input for dangerous characters, because any character may be dangerous under the right circumstances. You should encode at the point where some specific characters may become dangerous because they cross into a different sub-language where they have special meaning. When you write a string to HTML, you should encode characters that have special meaning in HTML, using Server.HtmlEncode. If you pass a string to a dynamic SQL statement, you should encode different characters (or better, let the framework do it for you by using prepared statements or the like)..

When you are sure you HTML-encode everywhere you pass strings to HTML, then set ValidateRequest="false" in the <%@ Page ... %> directive in your .aspx file(s).

In .NET 4 you may need to do a little more. Sometimes it's necessary to also add <httpRuntime requestValidationMode="2.0" /> to web.config (reference).

C# – How to create a dropdownlist from an enum in ASP.NET MVC

For MVC v5.1 use Html.EnumDropDownListFor

@Html.EnumDropDownListFor(
    x => x.YourEnumField,
    "Select My Type", 
    new { @class = "form-control" })

For MVC v5 use EnumHelper

@Html.DropDownList("MyType", 
   EnumHelper.GetSelectList(typeof(MyType)) , 
   "Select My Type", 
   new { @class = "form-control" })

For MVC 5 and lower

I rolled Rune's answer into an extension method:

namespace MyApp.Common
{
    public static class MyExtensions{
        public static SelectList ToSelectList<TEnum>(this TEnum enumObj)
            where TEnum : struct, IComparable, IFormattable, IConvertible
        {
            var values = from TEnum e in Enum.GetValues(typeof(TEnum))
                select new { Id = e, Name = e.ToString() };
            return new SelectList(values, "Id", "Name", enumObj);
        }
    }
}

This allows you to write:

ViewData["taskStatus"] = task.Status.ToSelectList();

by using MyApp.Common