占位符内容转换为字符串

本文关键字：字符串 转换 占位符 | 更新日期: 2023-09-27 17:52:50

简单的问题，但我找不到任何东西，是否有可能得到一个asp:占位符的内容字符串?如果可能的话，这将是伟大的服务器端。

《路加福音》

占位符内容转换为字符串

如果您只想要占位符的文本内容:

string textualContent = ((LiteralControl) PlaceHolder1.Controls[0]).Text;

返回 "Hello World" for:

<asp:PlaceHolder ID="PlaceHolder1" runat="server">Hello World</asp:PlaceHolder>

如果您还想获得渲染控件(及其所有子控件)的html:

System.IO.TextWriter tw = new System.IO.StringWriter();
HtmlTextWriter h = new HtmlTextWriter(tw);
PlaceHolder1.RenderControl(h);
string html = tw.ToString();

对于这个aspx (GridView绑定了一些相同的数据):

<asp:PlaceHolder ID="PlaceHolder1" runat="server">
    <asp:Label ID="LblTest" runat="server">Test-Label</asp:Label>
    <asp:TextBox ID="TxtTest" runat="server" Text="Foo"></asp:TextBox>
    <asp:GridView runat="server" ID="GridView1"></asp:GridView>
    <textarea name="TextArea1" rows="2" cols="1">
    First line
    Second line
    </textarea>
</asp:PlaceHolder>

这个HTML将被生成(取决于浏览器):

<span id="MainContent_LblTest">Test-Label</span><input name="ctl00$MainContent$TxtTest" type="text" value="Foo" id="MainContent_TxtTest" /><div>
    <table cellspacing="0" rules="all" border="1" id="MainContent_GridView1" style="border-collapse:collapse;">
        <tr>
            <th scope="col">ID</th><th scope="col">Text</th>
        </tr><tr>
            <td>1</td><td>Row #1</td>
        </tr><tr>
            <td>2</td><td>Row #2</td>
        </tr><tr>
            <td>3</td><td>Row #3</td>
        </tr><tr>
            <td>4</td><td>Row #4</td>
        </tr><tr>
            <td>5</td><td>Row #5</td>
        </tr>
    </table>
</div>
    <textarea name="TextArea1" rows="2" cols="1">
    First line
    Second line
    </textarea>

注意你需要把你的page指令改成

EnableEventValidation="false"

和覆盖Page中的VerifyRenderingInServerForm 

public override void VerifyRenderingInServerForm(Control control)
{
    /* Confirms that an HtmlForm control is rendered for the specified ASP.NET
       server control at run time. */
}

手动调用RenderControl

尝试Placeholder的RenderControl方法

我为HyperLink做了这样的事情，但是作为Placeholder继承自System.Web.UI.Control，这应该是完全相同的。像这样:

StringBuilder sb = new System.Text.StringBuilder();
using (var stringWriter = new System.IO.StringWriter(sb))
{
    using (var htmlTextWriter = new System.Web.UI.HtmlTextWriter(stringWriter))
    {
        YourPlaceHolder.RenderControl(htmlTextWriter);
    }
}
return sb.ToString();

我写了一篇关于这个话题的短文:http://www.tomot.de/en-us/article/3/asp.net/create-a-control-in-the-codebehind-and-retrieve-its-rendered-output

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