上传图片+预览

//上传图片

protected void btnAdd_Click(object sender, EventArgs e)
        {
            if (fupPic.HasFile)
            {
                String guid = Guid.NewGuid().ToString();
                String newFileName = folder + "\\" + guid + Path.GetExtension(fupPic.FileName);
                url = Page.ResolveUrl("~") + "temp/" + DateTime.Now.ToShortDateString() + "\\" + guid + Path.GetExtension(fupPic.FileName);
                //int totalFileSize = Int32.Parse(allFileSize.Value);
                int fileSize = fupPic.PostedFile.ContentLength;
                string type = fupPic.PostedFile.ContentType;
                if (type == "image/pjpeg")
                {
                    //此处也可以限制单个文件的大小
                    if (fileSize > 200 * 1024)
                    {
                        ClientScript.RegisterStartupScript(this.GetType(), "message", "<script>alert('上传图片大小不能超过200K ！')</script>");
                        return;
                    }

                    for (int i = 0; i < lbxFile.Items.Count; i++)
                    {
                        if (lbxFile.Items[i].Text.Equals(fupPic.FileName, StringComparison.InvariantCultureIgnoreCase))
                        {
                            ClientScript.RegisterStartupScript(this.GetType(), "message", "<script>alert('不能添加已经添加过的文件！')</script>");
                            return;
                        }
                    }
                    fupPic.SaveAs(newFileName);
                    ListItem item = new ListItem();
                    item.Text = fupPic.FileName;
                    item.Value = url + "|" + newFileName;
                    pre.Style["display"] = "";
                    pre.Src = url;
                    //totalFileSize += fileSize;
                    //allFileSize.Value = totalFileSize.ToString();
                    lbxFile.Items.Add(item);
                    PreViewImage();
                   
                }
                else
                {
                    ClientScript.RegisterStartupScript(this.GetType(), "message", "<script>alert('上传图片格式错误！');</script>");
                }
            }
        }

//预览

private void PreViewImage()
        {
            String p = "";
            for (int i = 0; i < lbxFile.Items.Count; i++)
            {
                p += "<img src='" + lbxFile.Items[i].Value.Split('|')[0] + "' style='width:100px;height:100px'>";
                if (i % 6 == 0 && i != 0)
                {
                    p += "<br />";
                }
            }
            x.InnerHtml = p;
        }

//上传图片删除

protected void btnDelete_Click(object sender, EventArgs e)
        {
            for (int i = lbxFile.Items.Count - 1; i > -1; i--)
            {
                if (lbxFile.Items[i].Selected)
                {
                    String value = lbxFile.Items[i].Value;
                    lbxFile.Items.Remove(lbxFile.Items[i]);
                    if (File.Exists(value.Split('|')[1]))
                    {
                        File.Delete(value.Split('|')[1]);
                    }
                }
            }
            PreViewImage();
            pre.Src = "";
            pre.Style["display"] = "none";
        }

//html代码

                    <TR>
                      <TD align=right bgColor=#f1f4f7 height=30>图片上传：</TD>
                      <TD style="PADDING-LEFT: 10px" align=left bgColor=#ffffff 
                      colSpan=3 height=30>
                          <asp:FileUpload ID="fupPic" runat="server" />
                            <asp:Button ID="btnAdd" runat="server" Text="添加文件" OnClick="btnAdd_Click" 
                              CausesValidation="False" />
                        </TD>
                    </TR>

                    <TR>
                      <TD align=right bgColor=#ffffff height=30>图片列表：</TD>
                      <TD style="PADDING-LEFT: 10px" align="left" bgColor=#ffffff 
                      colSpan=3 height=30>
                          <asp:ListBox ID="lbxFile" runat="server" Height="145px" Width="245px" CssClass="txt"></asp:ListBox>
                          <img alt="" src="" style="width: 100px; height: 100px; display: none;float:right" id="pre" runat="server" />
                        </TD>
                    </TR>

                    <TR>
                      <TD align=right bgColor=#f1f4f7 height=30>预览：</TD>
                      <TD style="PADDING-LEFT: 10px" bgcolor="#ffffff" colspan="3" align="left" id="x" runat="server">
                          
                        </TD>
                    </TR>

                    <TR>
                    <td bgColor=#ffffff></td>
                      <TD id=TD1 style="PADDING-RIGHT: 15px" align="left" bgColor="#ffffff" colSpan=3 height=30>
                          <asp:Button ID="btnDelete" runat="server" Text="删除图片" OnClick="btnDelete_Click" 
                              CausesValidation="False" /></TD>
                    </TR>