如何在C＃中将字典项传递给函数

Question

I am writing a custom helper to handle nested navigation menu. I am having some trouble with passing a set of arrays (or dictionary) to the function.

Below is the Razor call to the ActionMenuItem

@Html.ActionMenuItem("All Reports", "index", "report", "icon-bar-chart", "last", new {"title" = "Report 1", "action" = "report1"}, new {"title" = "Report 2", "action" = "report2"})
public static MvcHtmlString ActionMenuItem(this HtmlHelper htmlHelper, String linkText, String actionName, String controllerName, String iconType = null, string classCustom = null, params Dictionary<string, string> subMenu)

My function works well, up until the dictionary items. I am able to generate a single level menu, but trying to get it to work with nested menus.

Any help, and lessons is much appreciated!

Thank you,

RD

Answer 1

Could you do something like this:

public static MvcHtmlString ActionMenuItem(
    this HtmlHelper htmlHelper,
    String linkText,
    String actionName,
    String controllerName,
    String iconType = null,
    string classCustom = null,
    params KeyValuePair<string, string>[] subMenus)
{ ... }

var dict = new Dictionary<string, string>()
{
    { "a", "b" },
    { "c", "d" },
};

*.ActionMenuItem(*, *, *, *, *, dict.ToArray());

Answer 2

You can't declare Dictionary<TKey, TValue> as parameter array using params keyword.

According to c# specification:

A parameter declared with a params modifier is a parameter array. If a formal parameter list includes a parameter array, it must be the last parameter in the list and it must be of a single-dimensional array type .

Dictionary is not a single-dimensional array .

You could create a class with two properties: Title and Action and change parameter type to MyClass[] instead of a dictionary.

Answer 3

Try something like this:

    @Html.ActionMenuItem(
        "All Reports", 
        "index", 
        "report", 
        "icon-bar-chart", 
        "last", 
        new Dictionary<string, string>[]
        {
            new Dictionary<string, string>()
            {
                { "title", "Report 1" }, 
                { "action", "report1" }
            }, 
            new Dictionary<string, string>()
            {
                { "title",  "Report 2" },
                { "action", "report2" }
            }
        } )

    public static MvcHtmlString ActionMenuItem(
        this HtmlHelper htmlHelper, 
        string linkText, 
        string actionName, 
        string controllerName, 
        string iconType = null, 
        string classCustom = null, 
        params Dictionary<string, string>[] subMenu)