CODEWITHSUNDEEP
asp.net-mvcasp.net-mvc-2
Jarrod Nettles
Jarrod Nettles

Reputation: 6283

Custom DropdownFor in ASP.NET MVC2

I'm trying to build dropdowns automatically in my project by creating my own Html helper method that takes a "dropdown group" code and automatically builds the Html. However, it needs to do this while fully supporting the model.

My end code needs to look like this.

<%: Html.CodeList(m => m.state, 121) %>

... where "121" is the code group that returns a dictionary of key/value pairs from the database.

Here's what I have for my Html helper method so far.

    public static MvcHtmlString CodeList<T, TProp>(this HtmlHelper<T> html, Expression<Func<T, TProp>> expr, int category)
    {
        Dictionary<int, string> codeList = CodeManager.GetCodeList(category); //returns dictionary of key/values for the dropdown
        return html.DropDownListFor(expr, codeList, new Object()); //this line here is the problem
    }

I can't figure how what exactly to hand to the DropDownListFor method. I assume that I do return html.DropDownListFor() but I'm missing something obvious. Any help?

Upvotes: 0

Views: 244

Answers (1)

Darin Dimitrov
Darin Dimitrov

Reputation: 1038820

There you go:

public static MvcHtmlString CodeList<T, TProp>(
    this HtmlHelper<T> html, 
    Expression<Func<T, TProp>> expr, 
    int category
)
{
    var codeList = CodeManager.GetCodeList(category);

    var selectList = new SelectList(
        codeList.Select(item => new SelectListItem { 
            Value = item.Key.ToString(), 
            Text = item.Value
        }), 
        "Value", 
        "Text"
    );
    return html.DropDownListFor(expr, selectList);
}

Remark: static methods such as CodeManager.GetCodeList are very bad in terms of unit testing your components in isolation.

Upvotes: 1

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