how do I set disabled attribute on html textbox in

问题:

I am trying to dynamically set the disabled attribute on the html textbox and having issues

I tried this in my view:

 string disabledString = "";
 if (SomeLogic)
 {
      disabledString = "disabled";
 }

 Html.Textbox()...new Dictionary<string, object> { { "maxlength", 50 }, { "disabled", readOnlyState } })%>

As you can see I am setting the disabled attribute to "" or disabled but when I test, it seems to be disabled in either case. Am I missing something?

回答1:

This was ugly for us, due to the fact that the HTML spec is lousy here.

Basically in our view code we had some logic like this:

bool isPlatformOwner = false;

object disabledAttributes = new { @disabled="disabled", @readonly="readonly" };

//omitted code setting isPlatformOwner    

    if (isPlatformOwner)
    {
        disabledAttributes = new { };
    }

Then, for our controls, we had this:

<%=Html.CheckBoxFor(f => f.AddToReleaseIndicator, disabledAttributes)%>

Anonymous types saved us here, but, like I said, it got a little ugly.

回答2:

Actually it is possible to write an Extension class to the HtmlHelper to do this but you have to implement many overrides so the quickest solution I found was to write a dictionary extension.

You can use below class for this:

public static class DictionaryExtensions
{
    public static Dictionary<string, object> WithAttrIf(this Dictionary<string,object> dictionary,bool condition, string attrname, object value)
    {
        if (condition)
            dictionary[attrname] = value;

        return dictionary;
    }

    public static Dictionary<string, object> WithAttr(this Dictionary<string, object> dictionary, string attrname, object value)
    {

        dictionary[attrname] = value;

        return dictionary;
    }
}

To use it, import the class in your view and your view code looks like this:

@Html.TextBoxFor(m => m.FirstName,  new Dictionary<string, object>().WithAttr("class","input-large").WithAttrIf(!string.IsNullOrWhiteSpace(Model.FirstName),"readonly","yes"))

You can add as many attributes as you wish since the extension method adds the value to the dictionary and returns the dictionary itself

回答3:

I think you want to omit the disabled attribute altogether when you want it to be enabled. Older browsers would look at the following and disable the text boxes:

<input type="text" disabled></input>

In other words in older HTML the ="disabled" was not necessary so for compatibility reasons you should just omit the attribute if you want it to render right. I'm not sure what happens if you try a strict DOCTYPE, though.