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我正在将一些MVC页面添加到已存在的WebForms项目中。我想继续尽可能少地更改WebForms主页面/辅助方法。 WebForms项目使用asp:Menu来构建菜单导航,因此我制作了一个HTML助手方法,该方法动态构建相同的菜单,将控件呈现给包装StringBuilder的HtmlWriter,然后返回输出。将asp:菜单直接渲染到HtmlWriter
这里是我的代码:
<Extension()> _
Public Function RenderMenu(helper As HtmlHelper) As MvcHtmlString
'Build menu with asp .net standard menu control
Dim menuSource As New System.Web.UI.WebControls.SiteMapDataSource() With {
.ShowStartingNode = False,
.SiteMapProvider = "MySiteMapProvider"
}
Dim menuBuilder As New System.Web.UI.WebControls.Menu() With {
.CssClass = "menu",
.IncludeStyleBlock = "false",
.Orientation = System.Web.UI.WebControls.Orientation.Horizontal,
.StaticSubMenuIndent = New System.Web.UI.WebControls.Unit(20),
.RenderingMode = System.Web.UI.WebControls.MenuRenderingMode.List,
.DataSource = menuSource
}
menuBuilder.DynamicHoverStyle.BorderStyle = System.Web.UI.WebControls.BorderStyle.Dotted
Dim buffer As New StringBuilder()
Dim writer As New System.Web.UI.HtmlTextWriter(New StringWriter(buffer))
menuBuilder.RenderControl(writer)
'Convert rendered html to an mvc html string (to avoid re-encoding)
Return New MvcHtmlString(buffer.ToString())
End Function
问题是,什么是越来越呈现给我的HTMLWriter!我在调试器上通过了它,并确认我的menuSource有数据。我也尝试手动添加项目到菜单,但结果相同。
这可能是某种与菜单控件的Page属性没有被设置的问题?如果是这样,有没有办法将它伪造出来?
它似乎现在正在添加数据,但对RenderControl的调用抛出了NullReferenceException。 – 2012-07-10 12:02:41
没关系,我能够创建一个假窗体,只是渲染,而不是:Dim fakeForm As New System.Web.UI.HtmlControls.HtmlForm()With { .Page = New System.Web.UI.Page() } fakeForm.Controls.Add(menuBuilder) – 2012-07-10 12:06:11