Question

我有一个问题 - 如何在浏览器中显示图像而不在Temp文件夹中保存图像？它甚至可能吗？我的代码必须从数据库中读取图像并在网站中显示图像。我实际上尝试从数据库转换数据，我不知道我想做什么。我也尝试使用“imageHandlers”，“FileStream”，“Base64StringToBitmap”，但仍然无法正常工作...... 请编写示例代码或修改我的代码。

private void LoadImages()
{
ImageButton imageButton = new ImageButton();
string constr = ConfigurationManager.ConnectionStrings["DefaultConnection"].ConnectionString;
using (SqlConnection conn = new SqlConnection(constr))
{
    using (SqlCommand cmd = new SqlCommand())
    {
        cmd.CommandText = "select Id, Name, Data from tblFiles WHERE email = @CurrentUser";
        cmd.Parameters.Add("@CurrentUser", SqlDbType.NVarChar);
        cmd.Parameters["@CurrentUser"].Value = User.Identity.Name;
        cmd.Connection = conn;
        conn.Open();

        using (SqlDataReader sdr = cmd.ExecuteReader())
        {
            if (sdr.HasRows)
            {
                sdr.Read();

                string fileName = sdr["Name"].ToString();
                FileInfo fi = new FileInfo(fileName);
                byte[] byte_image_string = ((byte[])sdr["Data"]);
                string image_string = Convert.ToBase64String((byte[])sdr["Data"]) + fi.Name;

                imageButton.Height = Unit.Pixel(100);
                imageButton.Style.Add("padding", "5px");
                imageButton.Width = Unit.Pixel(100);
                imageButton.Click += new ImageClickEventHandler(imageButton_Click);
                Panel1.Controls.Add(imageButton);

                System.Drawing.Image newImage;

                if (byte_image_string != null)
                {
                    using (MemoryStream stream = new MemoryStream(byte_image_string))
                    {
                        newImage = System.Drawing.Image.FromStream(stream);

                        //I want here display image to browser without saving

                        //string newPhoto = "";
                        //newImage.Save(newPhoto);

                        imageButton.ImageUrl = "data:image/jpg;base64," + newPhoto;
                    }   
                }   
                conn.Close();
            }
        }    
    }
}
}

我在数据库中的示例图像代码：

0xFFD8FFE000104A46494600010100000100010000FFE1018C45786966000049492A0008000000020031010200070000002600000069870400010000002E00000000000000476F6F676C6500000500009007000400000030323230099007000B0000007000000086920700080100007B00000002A00400010000006F02000003A0

Answer 1

这就是我在我的一个项目中的表现：看看src部分

<p><a href='<%#"TheObject.aspx?O=" + Eval("ID") %>'><img runat="server" visible='<%#Eval("AttachmentID") != DBNull.Value %>' class="objPicture1" alt='<%Eval("Title") %>' width="340" height="260" src='<%#"~/Attachment.aspx?ID=" + Eval("AttachmentID")%>' /></a></p>

在Attachment.aspx中，您有以下代码：

    protected void Page_Load(object sender, EventArgs e)
    {
        Guid objID = //take the ID of the object ?ID=""

        DataRow attachmentRow = //fetch DataRow of the Attachment from Database

        if (attachmentRow == null)
            return;

        Response.ContentType = attachmentRow["ContentType"].ToString();// value of this is image/gif or image/jpeg and etc.
        Response.BinaryWrite((byte[])attachmentRow["Data"]); // Data is type image in my case                
        Response.End();
    }

Answer 2

看起来你正在以错误的方式创建Base64String。您正在向其附加不应该起作用的文件名。试试看。

string image_string = Convert.ToBase64String((byte[])sdr["Data"]);

直接将其分配给ImageUrl。这里不需要使用MemoryStream。

imageButton.ImageUrl = "data:image/jpg;base64," + image_string;

ASP.NET - 如何在浏览器中显示图像而不在temp中保存图像？

2 个答案: