Question

是否可以从查询字符串显示图像？

我的代码是这样的：

  <dx:GridViewDataTextColumn VisibleIndex="12" Width="7px">
            <DataItemTemplate>
                <asp:HyperLink ID="link" runat="server"  Target="_blank" OnInit="link_Photo">Photo</asp:HyperLink>
            </DataItemTemplate>
        </dx:GridViewDataTextColumn>

和cs。

protected void link_Photo(object sender, EventArgs e)
    {
        HyperLink link = sender as HyperLink;
        GridViewDataItemTemplateContainer container = link.NamingContainer as GridViewDataItemTemplateContainer;

        link.NavigateUrl = String.Format("Print_Photo.aspx?PtRamase={0}&PtLivre={1}", DataBinder.Eval(container.DataItem, "PHOTO_RAMASE"), DataBinder.Eval(container.DataItem, "PHOTO_LIVRER"));
    }

然后我弹出新窗口

      <dx:ASPxImage ID="ASPxImage_Ramase" runat="server">
            </dx:ASPxImage>

 public string Image_Ramase = "", Image_Livre = "";
    protected void Page_Load(object sender, EventArgs e)
    {
        try
        {
            Image_Ramase = Request.QueryString["PtRamase"];
            Image_Livre = Request.QueryString["PtLivre"];

            var bytes = Encoding.UTF8.GetBytes(Image_Ramase);
            var base64String = Convert.ToBase64String(bytes);
            ASPxImage_Ramase.ImageUrl = "data:image/png;base64," + base64String;
        }
        catch (Exception ex)
        {
            ASPxLabel_Err.Text = ex.Message;
        }

    }

我收到错误404.15 - 未找到似乎我在查询字符串中发布的数据太长了：

Print_Photo.aspx?PtRamase=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%22&PtLivre=

所以我认为不可能通过querystring传输base64数据。

Answer 1

你可以。但是，示例中的值超过2600字节，超过默认限制2048.要更改该限制，您需要修改web.config，如下所示

<system.web>
    <httpRuntime maxQueryStringLength="3000" />
</system.web>
<system.webServer>
   <security>
    <requestFiltering>
      <requestLimits maxQueryString="3000"/>
    </requestFiltering>
  </security>
<system.webServer>

其中3000是你的限制。有关详细信息，请查看How to configure the web.config to allow requests of any length

P.S。

您的代码似乎还有其他一些问题：

你得到一个字符串，将其转换为字节然后再转换为字符串，这毫无意义。
将对url字符串进行编码（例如“+”变为“”）
Image控件将自动解码其ImageUrl值，它可能无法在某些base64字符串上运行。

我会尝试使用HtmlImage Server Control（不应该解码值）而不是ASP.NET控件，并按如下方式修改代码：

<img id="Image1" runat="server" />

...

Image_Ramase = Request.QueryString["PtRamase"];
Image1.Src = "data:image/png;base64," + Image_Ramase.Replace(" ", "+");

通过querystring从base64显示图像

1 个答案: