我对MVC比较新,所以如果我从错误的角度攻击这个问题,请告诉我。
我有几种观点,我想以html和pdf格式提供给用户。使用HiQPdf dll,这是一个非常简单的任务,所以我只是想在我的Controller基类上包装一个辅助函数,所以我可以做类似的事情:
public ActionResult MyAction(MyActionVM model) {
if(Request.QueryString["type"] == "pdf") {
return Pdf("ViewName", model, "htmlaspdf.pdf");
}
return View("ViewName");
}
这是我到目前为止所执行的内容,它编译得很好,并且在我天真的自我看来它应该有效。但是,当我运行动作时,它会在Pdf()
函数的第一行失败,但下面的例外情况对我来说并没有多大意义。它显然是在调用ViewContext ctor,但我不确定为什么或如何修复它。有什么见解吗?
public class CustomBaseController : Controller {
protected FileResult Pdf(string viewname, object data, string filename) {
HtmlToPdf converter = new HtmlToPdf(); //Exception stack references this line
MemoryStream ms = new MemoryStream();
using (var sw = new StringWriter()) {
ViewResult view;
if (String.IsNullOrWhiteSpace(viewname))
view = this.View(data);
else
view = this.View(viewname, data);
//roughly taken from the examples here: http://blog.janjonas.net/2011-06-18/aspnet-mvc3-controller-extension-method-render-partial-view-string
var viewContext = new ViewContext(this.ControllerContext, view.View, ViewData, TempData, sw);
view.View.Render(viewContext, sw);
converter.ConvertHtmlToStream(sw.GetStringBuilder().ToString(), null, ms);
}
ms.Position = 0;
return File(ms, "application/octet-stream", filename);
}
}
异常
[ArgumentNullException: Value cannot be null.
Parameter name: view]
System.Web.Mvc.ViewContext..ctor(ControllerContext controllerContext, IView view, ViewDataDictionary viewData, TempDataDictionary tempData, TextWriter writer) +326
MyNamespace.Utilities.MyNamespaceController.Pdf(String viewname, Object data, String filename) in G:\brendans\Projects\MyNamespace\MyNamespace\Utilities\MyNamespaceController.cs:21
答案 0 :(得分:0)
感谢Daniel J.G.这种轻微的修改非常有效。
MemoryStream ms = new MemoryStream();
HtmlToPdf converter = new HtmlToPdf();
ViewData.Model = model;
using (var sw = new StringWriter()) {
var viewengineresult = ViewEngines.Engines.FindPartialView(this.ControllerContext, viewname);
var viewcontext = new ViewContext(this.ControllerContext, viewengineresult.View, ViewData, TempData, sw);
viewengineresult.View.Render(viewcontext, sw);
converter.ConvertHtmlToStream(sw.GetStringBuilder().ToString(), null, ms);
}
ms.Position = 0;
return File(ms, "application/octet-stream", filename);