How to Create a Generic Method and Create Instance of The Type
I want to create a helper method that I can imagine has a signature similar to this:
public static MyHtmlTag GenerateTag<T>(this HtmlHelper htmlHelper, object obj)
{
// how do I create an instance of MyAnchor?
// this returns MyAnchor, which has a MyHtmlTag base
}
When I invoke the method, I want to specify a type of MyHtmlTag, such as MyAnchor, e.g.:
<%= Html.GenerateTag<MyAnchor>(obj) %>
or
&l开发者_如何学运维t;%= Html.GenerateTag<MySpan>(obj) %>
Can someone show me how to create this method?
Also, what's involved in creating an instance of the type I specified? Activator.CreateInstance()
?
Thanks
Dave
You'd use Activator.CreateInstance<T>
:
public static MyHtmlTag GenerateTag<T>(this HtmlHelper htmlHelper, object obj)
{
T value = Activator.CreateInstance<T>();
// Set properties on value/ use it/etc
return value;
}
There's existing functionality in MvcContrib you may want to check out called "FluentHtml". It looks like this:
<%=this.TextBox(x => x.FirstName).Class("required").Label("First Name:")%>
<%=this.Select(x => x.ClientId).Options((SelectList)ViewData["clients"]).Label("Client:")%>
<%=this.MultiSelect(x => x.UserId).Options(ViewModel.Users)%>
<%=this.CheckBox("enabled").LabelAfter("Enabled").Title("Click to enable.").Styles(vertical_align => "middle")%>
You need to add the generic constraint of new() to T, then do the following:
public static MyHtmlTag GenerateTag<T> (this HtmlHelper helper, T obj) where T : MyHtmlTag, new()
{
T val = new T ();
return val;
}
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