無法訪問在HTML中定義的圖像控件，在C＃文件後面的代碼中

Question

我正在忙於一個項目，並且我試圖在單擊按鈕時更改圖像。問題是我無法在代碼部分調用圖像控件。我怎樣才能調用圖像控件？

我曾嘗試將控件添加到designer.cs文件，但我無法訪問UI控件，我也嘗試了許多其他方法，但它沒有解決問題。

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Web; 
using System.Web.UI; 
using System.Web.UI.WebControls; 
using INF3014F_BMW_TEAM16.Models; 
using System.Web.ModelBinding; 



namespace INF3014F_BMW_TEAM16 
{ 
    public partial class ProductDetails : System.Web.UI.Page 
    { 
     protected void Page_Load(object sender, EventArgs e) 
     { 

    } 

    public IQueryable<Product> GetProduct(
        [QueryString("ProductID")] int? productId, [RouteData] string productName) 

    { 
     var _db = new INF3014F_BMW_TEAM16.Models.ProductContext(); 
     IQueryable<Product> query = _db.Products; 
     if (productId.HasValue && productId > 0) 
     { 
      query = query.Where(p => p.ProductID == productId); 
     } 
     else if (!String.IsNullOrEmpty(productName)) 
     { 
       query = query.Where(p => 
       String.Compare(p.ProductName, productName) == 0); 
     } 
     else 
     { 
      query = null; 
     } 
     return query; 
    } 

    protected void RedBtn_Click(object sender, EventArgs e) 
    { 
     Image1.ImageUrl = "/Catalog/Images/1hacth3red.jpg";    
    } 

<asp:FormView ID="productDetail" runat="server" ItemType="INF3014F_BMW_TEAM16.Models.Product" SelectMethod ="GetProduct" RenderOuterTable="false" OnPageIndexChanging="productDetail_PageIndexChanging"> 
    <ItemTemplate> 
     <div> 
      <h1><%#:Item.ProductName %></h1> 
     </div> 
     <br /> 
     <table> 
      <tr> 
       <td>    

         <Image id="Image1" src="/Catalog/Images/<%#:Item.ImagePatheWhite %>" style="border: solid; height: 300px" alt="<%#:Item.ProductName %>" runat ="server" /> 


       </td> 
       <td>&nbsp;</td> 
       <td style="vertical-align: top; text-align:left;"> 
        <b>Description:</b><br /><%#:Item.Description %><br /><span> 
        <b>Price:</b>&nbsp;<%#: String.Format("{0:c}", Item.UnitPrice) %></span><br /><span> 
        <b>Product Number:</b>&nbsp;<%#:Item.ProductID %></span><br /> 
        <br /> 
        <asp:Button ID="WhiteBtn" runat="server" Text="White" BackColor ="White" OnClick ="WhiteBtn_Click" /> 
        <<asp:Button ID="BlackBtn" runat="server" Text="Black" BackColor ="Black" /> 
        <asp:Button ID="RedBtn" runat="server" Text="Red" BackColor ="Red" OnClick ="RedBtn_Click" /> 
        <br /> 
         <a href="/AddToCart.aspx?productID=<%#:Item.ProductID %>">    
            <span class="ProductListItem"> 
             <b>Add To Cart<b> 
            </span>   
           </a> 
        <br /> 

       </td> 
      </tr> 
     </table> 
    </ItemTemplate> 
</asp:FormView> 

Answer 1

用戶服務器控制：

<asp:Image ID="Image1" runat="server" ImageUrl="/Catalog/Images/<%# Item.ImagePatheWhite %>" AlternateText="<%#:Item.ProductName %>" BorderColor="Black" Height="300px" /> 

<Image>標籤不存在，你必須使用標籤和使用屬性runat="server"

<img alt="" src="" /> 

Answer 2

我覺得應該是：

<asp:Image id="Image1" runat="server" ... etc./> 

，只是設置的ImageUrl服務器端。