從實體框架的數據庫加載圖像到gridview中

Question

我已經使用實體框架從標準Northwind數據庫創建了一個模型。 現在我想填充一個類別列表Gridview，但在該類別實體（表）也是一個圖片以及。 GridView獲取了Id，Description和CategoryName，但是我沒有在gridview列表中獲取二進制數據的圖片。

任何人都知道這個解決方案嗎？

謝謝。

Answer 1

你可以像這樣......

你要添加新的通用處理器-------右擊Solution Explorer中增加新的通用處理程序並將其命名爲「ImageHandler.ashx 」

注意：這是關於如何加載從數據庫和顯示圖像中的GridView

只有樣品例如，這是在imagehandler.ashx代碼

<%@ WebHandler Language="C#" %> 

using System; 
using System.Web; 
using System.IO; 
using System.Drawing.Imaging; 
using System.Collections.Generic; 
using System.Linq; 

public class ImageHandler : IHttpHandler { 

    public void ProcessRequest (HttpContext context) 
    { 
     HttpRequest req = context.Request;   
     // string categoryID = "1";   
     string categoryID = req.QueryString["CategoryID"].ToString();   
     // Get information about the specified category   
     NorthwindDataContext db = new NorthwindDataContext();   
     var category = from c in db.Categories       
         where Convert.ToInt32(c.CategoryID) == Convert.ToInt32(categoryID) 
         select c.Picture;   
     int len = category.First().Length;   
     // Output the binary data   
     // But first we need to strip out the OLE header   
     int OleHeaderLength = 78;   
     int strippedImageLength = len - OleHeaderLength;   
     byte[] imagdata = new byte[strippedImageLength];   
     Array.Copy(category.First().ToArray(), OleHeaderLength, imagdata, 0, strippedImageLength);   
     if ((imagdata) != null)   
     {    
      MemoryStream m = new MemoryStream(imagdata);    
      System.Drawing.Image image = System.Drawing.Image.FromStream(m);    
      image.Save(context.Response.OutputStream, ImageFormat.Jpeg);   
     } 
    } 

    public bool IsReusable { 
     get { 
      return false; 
     } 
    } 
} 

和在Default.aspx頁面添加新的GridView控件使用SQLDataSource控件

<div> 

    <asp:GridView ID="GridView1" runat="server" AllowPaging="True" 
     AutoGenerateColumns="False" DataKeyNames="CategoryID" 
     DataSourceID="SqlDataSource1" CellPadding="4" ForeColor="#333333" 
     GridLines="None"> 
     <RowStyle BackColor="#EFF3FB" /> 
     <Columns> 
      <asp:BoundField DataField="CategoryID" HeaderText="CategoryID" 
       InsertVisible="False" ReadOnly="True" SortExpression="CategoryID" /> 
      <asp:BoundField DataField="CategoryName" HeaderText="CategoryName" 
       SortExpression="CategoryName" /> 
      <asp:BoundField DataField="Description" HeaderText="Description" 
       SortExpression="Description" /> 
      <asp:TemplateField HeaderText="Picture" SortExpression="Picture"> 
       <EditItemTemplate> 
        <asp:TextBox ID="TextBox1" runat="server" Text='<%# Bind("Picture") %>'></asp:TextBox> 
       </EditItemTemplate> 
       <ItemTemplate> 
        <asp:Image ID="Image1" runat="server" ImageUrl='<%#"ImageHandler.ashx?CategoryID="+ Eval("CategoryID") %>'/> 
       </ItemTemplate> 
      </asp:TemplateField> 
     </Columns> 
     <FooterStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" /> 
     <PagerStyle BackColor="#2461BF" ForeColor="White" HorizontalAlign="Center" /> 
     <SelectedRowStyle BackColor="#D1DDF1" Font-Bold="True" ForeColor="#333333" /> 
     <HeaderStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" /> 
     <EditRowStyle BackColor="#2461BF" /> 
     <AlternatingRowStyle BackColor="White" /> 
    </asp:GridView> 
    <asp:SqlDataSource ID="SqlDataSource1" runat="server" 
     ConnectionString="<%$ ConnectionStrings:NorthwindConnectionString %>" 
     SelectCommand="SELECT * FROM [Categories]"></asp:SqlDataSource> 

</div> 

綁定它，我希望它會幫助你......