[匯入]ASP.NET 2.0 CSS Friendly Control Adapters 1.0版正式發布

選擇了ASP.NET的開發人員一直都很鬱悶，因為選擇了ASP.NET就是選擇了它已有的強大的Web控制項陳列庫，然後選擇了這些控制項的強大功能的同時也帶了一些問題，比如現在的有些複雜控制項，它輸出的HTML並不符合現在的WEB標準，例如GridView，TreeView，使用者控制項等等這些控制項輸出的HTML都是傳統的Table的方式，並不像WEB標準倡導的用控制顯示方式的CSS和內容Div分離的方式！

ASP.NETTeam Dev也意識到這個這問題，藉助於ASP.NET 2.0架構強大的可配置、可自訂能力，給出瞭解決問題的完美方案——使用.blowser檔案為頁面中的控制項配置自訂的Adapter，來替代原有的非標準的解決方案。這些自訂的Adapter的集合就是ASP.NET 2.0 CSS Friendly Control Adapters。在發布了若干個測試版本之後，ASP.NET 2.0 CSS Friendly Control Adapters 的1.0版本終於正式發布。

ASP.NET 2.0中這些不符合Web標準的控制項如下，每一種都在ASP.NET 2.0 CSS Friendly Control Adapters中提供了符合Web標準的替代實現。

1. Menu
2. TreeView
3. DetailsView
4. FormView
5. GridView
6. DataList
7. Login
8. ChangePassword
9. PasswordRecovery
10. CreateUserWizard
11. LoginStatus

在App_Browsers檔案夾下，可以看到CSSFriendlyAdapters.browser檔案，我們來看看它是如何配置的

<browsers>
  <browser refID="Default">
    <controlAdapters>
      <adapter controlType="System.Web.UI.WebControls.Menu"
               adapterType="CSSFriendly.MenuAdapter" />
      <adapter controlType="System.Web.UI.WebControls.TreeView"
               adapterType="CSSFriendly.TreeViewAdapter" />
      <adapter controlType="System.Web.UI.WebControls.DetailsView"
               adapterType="CSSFriendly.DetailsViewAdapter" />
      <adapter controlType="System.Web.UI.WebControls.FormView"
               adapterType="CSSFriendly.FormViewAdapter" />
      <adapter controlType="System.Web.UI.WebControls.DataList"
               adapterType="CSSFriendly.DataListAdapter" />
      <adapter controlType="System.Web.UI.WebControls.GridView"
               adapterType="CSSFriendly.GridViewAdapter" />
      <adapter controlType="System.Web.UI.WebControls.ChangePassword"
               adapterType="CSSFriendly.ChangePasswordAdapter" />
      <adapter controlType="System.Web.UI.WebControls.Login"
               adapterType="CSSFriendly.LoginAdapter" />
      <adapter controlType="System.Web.UI.WebControls.LoginStatus"
               adapterType="CSSFriendly.LoginStatusAdapter" />
      <adapter controlType="System.Web.UI.WebControls.CreateUserWizard"
               adapterType="CSSFriendly.CreateUserWizardAdapter" />
      <adapter controlType="System.Web.UI.WebControls.PasswordRecovery"
               adapterType="CSSFriendly.PasswordRecoveryAdapter" />
    </controlAdapters>
  </browser>

  <browser parentID="default">
    <identification>
      <userAgent match="^W3C_Validator" />
    </identification>
    <capabilities>
      <capability               value="W3C Validator" />
      <capability     value="1.2" />
      <capability            value="true" />
      <capability           value="true" />
      <capability      value="true" />
      <capability                value="true" />
      <capability             value="System.Web.UI.HtmlTextWriter" />
      <capability         value="1.0" />
    </capabilities>
  </browser>
</browsers>
我們可以看到這些像System.Web.UI.WebControls.Menu一樣的Web控制項都配置了adapterType屬性CSSFriendly.MenuAdapter

下面我們再來看看CSSFriendly.MenuAdapter裡面的一些代碼

private void BuildItems(MenuItemCollection items, bool isRoot, HtmlTextWriter writer)
        {
            if (items.Count > 0)
            {
                writer.WriteLine();

                writer.WriteBeginTag("ul");
                if (isRoot)
                {
                    writer.WriteAttribute("class", "AspNet-Menu");
                }
                writer.Write(HtmlTextWriter.TagRightChar);
                writer.Indent++;
                              
                foreach (MenuItem item in items)
                {
                    BuildItem(item, writer);
                }

                writer.Indent--;
                writer.WriteLine();
                writer.WriteEndTag("ul");
            }
        }

 

 private void BuildItem(MenuItem item, HtmlTextWriter writer)
        {
            Menu menu = Control as Menu;
            if ((menu != null) && (item != null) && (writer != null))
            {
                writer.WriteLine();
                writer.WriteBeginTag("li");

                string theClass = (item.ChildItems.Count > 0) ? "AspNet-Menu-WithChildren" : "AspNet-Menu-Leaf";
                string selectedStatusClass = GetSelectStatusClass(item);
                if (!String.IsNullOrEmpty(selectedStatusClass))
                {
                    theClass += " " + selectedStatusClass;
                }
                writer.WriteAttribute("class", theClass);

                writer.Write(HtmlTextWriter.TagRightChar);
                writer.Indent++;
                writer.WriteLine();

                if (((item.Depth < menu.StaticDisplayLevels) && (menu.StaticItemTemplate != null)) ||
                    ((item.Depth >= menu.StaticDisplayLevels) && (menu.DynamicItemTemplate != null)))
                {
                    writer.WriteBeginTag("div");
                    writer.WriteAttribute("class", GetItemClass(menu, item));
                    writer.Write(HtmlTextWriter.TagRightChar);
                    writer.Indent++;
                    writer.WriteLine();

                    MenuItemTemplateContainer container = new MenuItemTemplateContainer(menu.Items.IndexOf(item), item);
                    if ((item.Depth < menu.StaticDisplayLevels) && (menu.StaticItemTemplate != null))
                    {
                        menu.StaticItemTemplate.InstantiateIn(container);
                    }
                    else
                    {
                        menu.DynamicItemTemplate.InstantiateIn(container);
                    }
                    container.DataBind();
                    container.RenderControl(writer);

                    writer.Indent--;
                    writer.WriteLine();
                    writer.WriteEndTag("div");
                }
                else
                {
                    if (IsLink(item))
                    {
                        writer.WriteBeginTag("a");
                        if (!String.IsNullOrEmpty(item.NavigateUrl))
                        {
                            writer.WriteAttribute("href", Page.Server.HtmlEncode(menu.ResolveClientUrl(item.NavigateUrl)));
                        }
                        else
                        {
                            writer.WriteAttribute("href", Page.ClientScript.GetPostBackClientHyperlink(menu, "b" +  item.ValuePath.Replace(menu.PathSeparator.ToString(), "\\"), true));
                        }

                        writer.WriteAttribute("class", GetItemClass(menu, item));
                        WebControlAdapterExtender.WriteTargetAttribute(writer, item.Target);

                        if (!String.IsNullOrEmpty(item.ToolTip))
                        {
                            writer.WriteAttribute("title", item.ToolTip);
                        }
                        else if (!String.IsNullOrEmpty(menu.ToolTip))
                        {
                            writer.WriteAttribute("title", menu.ToolTip);
                        }
                        writer.Write(HtmlTextWriter.TagRightChar);
                        writer.Indent++;
                        writer.WriteLine();
                    }
                    else
                    {
                        writer.WriteBeginTag("span");
                        writer.WriteAttribute("class", GetItemClass(menu, item));
                        writer.Write(HtmlTextWriter.TagRightChar);
                        writer.Indent++;
                        writer.WriteLine();
                    }

                    if (!String.IsNullOrEmpty(item.ImageUrl))
                    {
                        writer.WriteBeginTag("img");
                        writer.WriteAttribute("src", menu.ResolveClientUrl(item.ImageUrl));
                        writer.WriteAttribute("alt", !String.IsNullOrEmpty(item.ToolTip) ? item.ToolTip : (!String.IsNullOrEmpty(menu.ToolTip) ? menu.ToolTip : item.Text));
                        writer.Write(HtmlTextWriter.SelfClosingTagEnd);
                    }

                    writer.Write(item.Text);

                    if (IsLink(item))
                    {
                        writer.Indent--;
                        writer.WriteEndTag("a");
                    }
                    else
                    {
                        writer.Indent--;
                        writer.WriteEndTag("span");
                    }

                }

                if ((item.ChildItems != null) && (item.ChildItems.Count > 0))
                {
                    BuildItems(item.ChildItems, false, writer);
                }

                writer.Indent--;
                writer.WriteLine();
                writer.WriteEndTag("li");
            }
        }
可以看出來，通過設定檔.Browser檔案配置每個控制項所用到的System.Web.UI.WebControls.Adapters，使用這些自訂的Adapters來改變控制項的HTML輸出！