Question

I have an issue in asp.net 4.

When I add an attribute on controls, then the render it encoded.

For example, when I type this code

txtQuestion.Attributes["onfocus"] = 
    "if(this.value == this.title)
{
   this.value = '';
   this.style.backgroundColor='#FEFDE0';
   this.style.color='#000000';
}";

I get render

onfocus="if(this.value == this.title){this.value = 
'';this.style.backgroundColor='#FEFDE0';
this.style.color='#000000';}"

And every ‘ hash been change to & #39;

Is there a way to disable this new future only on some controls ? or an easy way to make a custom render ?

My Fail tries

I have all ready try some thinks but I fail.
For example this fails.

txtQuestion.RenderingCompatibility = new Version("3.5");

I also locate the point that this attributes renders and is on

public virtual void RenderBeginTag(HtmlTextWriterTag tagKey) function,

there every attribute have a flag if he wish to be encoded, but I do not know how can anyone set it or not.

One Work Around

In the asp net forum in the same question, there is a solution that change the global EncodeType – this is not the solution that I search for – and the person that give the solution say that this is not a great workaround, with potential security issues or other render issues.

Thank you all in advanced.

By Kervin

Until now Kervin found that Microsoft suggest instead use this command.

txtQuestion.Attributes["onfocus"] = 
    "if(this.value == this.title){this.value = '';this.style.backgroundColor='#FEFDE0';this.style.color='#000000';}";

Use this one.

    Page.ClientScript.RegisterExpandoAttribute(txtQuestion.ClientID, "onfocus", 
 "if(this.value == this.title){this.value = '';this.style.backgroundColor='#FEFDE0';this.style.color='#000000';}");

And what MS render, is on the end of the page, a script that add onfocus on this control using JavaScript.
We can do that even by our self with jQuery and probably be more compatible.

This is a solution, but still I am wish to know if there is a way to just avoid the Attribute Encoding and let me do what I wish my way – not MS way.

Answer 1

From MSDN WebControl.Attributes Property Documentation…

Note

You cannot add client-side script to a WebControl instance using the Attributes collection. To add client-side script, use the ClientScript property on the Page control.

The problem is that Attributes expects data if it’s being set in the code-behind.

The solution is to send back a client script with your client side handler functions then you may set the attribute with the name of your functions.

If your javascript is static, then things are even simpler, since you can send them in a script tag long before the controls are registered.