0

我在数据库中有两个表，其中有“图像”类型的字段，在另一个表中有我想在 FormView 中检索的字段。formView 显示来自另一个表的字段，但不显示图像控件中的图像。.aspx 文件

<asp:FormView runat="server" ID="ListStories" DefaultMode="ReadOnly" >
<ItemTemplate>
<table>
<tr><td><%#Eval("Subject") %></td></tr>
<tr><td><%#Eval("Story") %></td></tr>
<tr><td><%#Eval("UserName")%> </td></tr>

</table>
<asp:Image ID="Image1" runat="server" ImageUrl = '~/ShowImage.ashx?Name=<%#Eval("UserName") %>'  Width="150" Height="150" />
</ItemTemplate>


</asp:FormView>

后面的代码：

protected void Page_Load(object sender, EventArgs e)
    {
        RetriveStories();

    }

    protected void RetriveStories()
    {

        conn = new SqlConnection(connString);
        cmdStories = new SqlCommand("SELECT UserName, Subject, Story FROM Stories", conn);

        conn.Open();
        reader = cmdStories.ExecuteReader();


        ListStories.DataSource = reader;
        ListStories.DataBind();

        conn.Close();

    }

图像处理程序：

public class ShowImage : IHttpHandler
{
    public void ProcessRequest(HttpContext context)
    {
        string userName = HttpContext.Current.Request.QueryString["Name"];

        context.Response.ContentType = "image/jpeg";
        Stream strm = ShowEmpImage(userName);
        try
        {
            byte[] buffer = new byte[4096];
            int byteSeq = strm.Read(buffer, 0, 4096);

            while (byteSeq > 0)
            {
                context.Response.OutputStream.Write(buffer, 0, byteSeq);
                byteSeq = strm.Read(buffer, 0, 4096);
            }
        }
        catch (NullReferenceException)
        {
            context.Response.WriteFile("img/default.png");
        }
    }

    public Stream ShowEmpImage(string name)
    {
        string connString = ConfigurationManager.ConnectionStrings["Alumnidb"].ConnectionString;
        SqlConnection conn = new SqlConnection(connString);
        SqlCommand cmdRetiveImage = new SqlCommand("SELECT Photo FROM UserProfile WHERE UserName=@UserName", conn);
        cmdRetiveImage.CommandType = CommandType.Text;
        cmdRetiveImage.Parameters.AddWithValue("@UserName", name);
        conn.Open();
        object img = cmdRetiveImage.ExecuteScalar();
        try
        {
            return new MemoryStream((byte[])img);
        }
        catch
        {
            return null;
        }
        finally
        {
            conn.Close();
        }
    }

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

但是图像处理程序总是执行这些行

catch (NullReferenceException)
            {
                context.Response.WriteFile("img/default.png");
            }

为什么它在我传递查询字符串时不起作用但它仍然执行空值？您的帮助将不胜感激。谢谢

4

2 回答 2

0

替换这个：

... ImageUrl = '~/ShowImage.ashx?Name=<%#Eval("UserName") %>' ...

和

... ImageUrl = '<%# "~/ShowImage.ashx?Name=" + Server.UrlEncode(Eval("UserName").ToString()) %>' ...

它应该可以工作。

于 2013-06-27T12:05:21.943 回答
0

tyy 这段代码。会帮助你

public void ProcessRequest(HttpContext context)
    {
        string userName = context.Request.QueryString["Name"];

        context.Response.ContentType = "image/jpeg";
        Stream strm = ShowEmpImage(userName);
        try
        {
            byte[] buffer = new byte[4096];
            int byteSeq = strm.Read(buffer, 0, 4096);

            while (byteSeq > 0)
            {
                context.Response.OutputStream.Write(buffer, 0, byteSeq);
                byteSeq = strm.Read(buffer, 0, 4096);
            }
        }
        catch (NullReferenceException)
        {
            context.Response.WriteFile("img/default.png");
        }
    }
于 2013-06-27T11:12:25.680 回答