上传图片到文件夹并显示在GridView控件里面

http://aspsnippets.com/Articles/Upload-images-to-folder-and-display-uploaded-images-in-ASPNet-GridView-using-C-and-VBNet.aspx

1. Html 页面

 <div>
    <asp:FileUpload ID="FileUpload1" runat="server" />
    <asp:Button ID="btnUpload" runat="server" Text="Upload" OnClick="btnUpload_Click" /><hr />
    <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false" ShowHeader="false">
    <Columns>
        <asp:BoundField DataField="Text" />
        <asp:ImageField DataImageUrlField="Value" ControlStyle-Height="100" ControlStyle-Width="100" />
    </Columns>
</asp:GridView>
    </div>

2. 添加命名空间

using System.IO;
using System.Collections.Generic;

3. 上传文件按钮事件

   protected void btnUpload_Click(object sender, EventArgs e)
        {
            if (FileUpload1.HasFile)
            {
                string fileName = Path.GetFileName(FileUpload1.PostedFile.FileName);
                FileUpload1.PostedFile.SaveAs(Server.MapPath("~/Image/") + fileName);
                Response.Redirect(Request.Url.AbsoluteUri);
            }
        }

4.Page_Load 事件--加载图片并显示在GridView中

 protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                string[] filePaths = Directory.GetFiles(Server.MapPath("~/Image/"));
                List<ListItem> files = new List<ListItem>();
                foreach (string filePath in filePaths)
                {
                    string fileName = Path.GetFileName(filePath);
                    files.Add(new ListItem(fileName, "~/Image/" + fileName));
                }
                GridView1.DataSource = files;
                GridView1.DataBind();
            }
        }

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从数据库获取binary形式存储的文件（[Image]是图片字段，以Binary形式存储）

http://www.beansoftware.com/ASP.NET-Tutorials/Save-Read-Image-Database.aspx

protected void btnDisplayImage_Click(object sender, EventArgs e)
        {
            using (SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnStr"].ConnectionString))
            {
                conn.Open();
                SqlCommand cmd = new SqlCommand("select[Image] from SaveImageByBinary where id =1",conn);
                byte[] img=(byte[])cmd.ExecuteScalar();
                MemoryStream ms = new MemoryStream();
                ms.Write(img, 0, img.Length);

                Bitmap bt = new Bitmap(ms);
                Response.ContentType = "image/jpeg";
                //bt.Save(Response.OutputStream, ImageFormat.Jpeg);
                string filename = Server.MapPath("~/Image/12456.jpeg");
                bt.Save(Response.OutputStream, ImageFormat.Jpeg);
            }
        }