Question

虽然我们在Substitution控件中使用的方法应该返回字符串，那么如何在服务器控件上的Web表单中使用donut caching，这应该是服务器端？例如Loginview控件？

Answer 1

遗漏了Micah的一个问题是，替换函数必须为static，接受HttpContext参数，然后返回string。有关详细信息，请参阅this msdn page。

我还将Micah的助手类扩展得更灵活一些。

<强>标记

<asp:Substitution ID="Substitution1" MethodName="myFunction" runat="server" />

<强>实行

public static string myFunction(HttpContext httpContext){
   ViewManager vm = new ViewManager();

   //example using a Button control

   Button b = new Button();
   b.Text = "click me"; //we can set properties like this

   //we can also set properties with a Dictionary Collection
   Dictionary<string,object> data =  new Dictionary<string,object>();
   data.add("Visible",true); 

   String s = vm.RenderView(b,data); //don't do anything (just for example)

   //we can also use this class for UserControls
   UserControl myControl = vm.GetUserControl("~mypath");

   data.clear();
   data.add("myProp","some value");

   return vm.RenderView(myControl,data); //return for Substitution control
}

<强>类

using System.IO;
using System.ComponentModel;
public class ViewManager
{
    private PageForRenderingUserControl pageHolder;
    public ViewManager()
    {
        pageHolder = new PageForRenderingUserControl();
    }

    public UserControl GetUserControl(string path)
    {
        return (UserControl)pageHolder.LoadControl(path);
    }

    public string RenderView(Control viewControl, Dictionary<string, object> data)
    {
        pageHolder.Controls.Clear();
        //Dim viewControl As UserControl = DirectCast(pageHolder.LoadControl(Path), UserControl)

        if (data != null) {
            Type viewControlType = viewControl.GetType();


            dynamic properties = TypeDescriptor.GetProperties(viewControl);

            foreach (string x in data.Keys) {
                if ((properties.Item(x) != null)) {
                    properties.Item(x).SetValue(viewControl, data[x]);
                }
            }
        }

        pageHolder.Controls.Add(viewControl);
        StringWriter result = new StringWriter();
        HttpContext.Current.Server.Execute(pageHolder, result, false);
        return result.ToString();
    }

    private class PageForRenderingUserControl : Page
    {
        public override void VerifyRenderingInServerForm(Control control)
        {
            // Do nothing 
        }

        public override bool EnableEventValidation {
            get { return false; }
            // Do nothing 
            set { }
        }
    }

}

再次感谢Micah代码

Answer 2

我相当确定你不能这样做 - Substitution控件只能允许你将一个字符串插入一个outputcached页面。
如果你考虑一下服务器控件的整个输出，这是有道理的，这可能是<table>，它会破坏你所有精心设计的标记和/或需要加载<script>加载到{页面 - 而注入单个字符串是相对简单的。

如何在Substitution控件中使用ASP.Net服务器控件？

3 个答案: