ASP. NET Gridview с DataSourceID, не связанным должным образом

Question

У меня есть страница, которая использует gridview, которая объявила идентификатор datasourceID, файлы отображаются правильно. Тем не менее, всякий раз, когда я обновляю фотографию gridview, gridview не обновляется правильно, несмотря на фотографию в моих папках, где gridview извлекает из обновления. Единственный способ, которым я могу заставить их получить правильные фотографии, - это если я на самом деле нажимаю F5 или перезагружаю проект. Сетка также находится внутри панели обновления.

<asp:UpdateProgress ID="UpdateProgress1" AssociatedUpdatePanelID="UpdatePanel1" runat="server"> 
    <ProgressTemplate> 
     <div class="overlay" align="center"> 
      <div class="over"> 
      <img alt="progress" src="images/loader.gif"/> 
      Processing...  </div> 
    </div> 
     </ProgressTemplate> 
</asp:UpdateProgress> 
<asp:UpdatePanel ID="UpdatePanel1" runat="server" UpdateMode="Always"> 
    <ContentTemplate> 
<div id="staffList"> 
<asp:SqlDataSource ID="SqlDataSource1" runat="server" EnableViewState="false" EnableCaching="false" ConnectionString="<%$ ConnectionStrings:Database1Entities %>" 
       SelectCommand="SELECT * FROM (SELECT Staff.[StaffID], Staff.[StaffName], Staff.[PhoneNo], Staff.[Photo], Staff.[EmpmType], Staff.[AcadStaff], Designation.[DesignationName], Section.[SectionName], Groups.[GroupName], Staff.[InternetAddr], ROW_NUMBER() OVER(ORDER BY Designation.[SortingOrder]) AS Rownum FROM Staff LEFT JOIN Designation ON Designation.[DesignationID] = Staff.[DesignationID] LEFT JOIN Groups ON Groups.[GroupID] = Staff.[GroupID] LEFT JOIN Section ON Section.[SectionID] = Staff.[SectionID] WHERE (Staff.[StaffName] IS NOT NULL)) AS test1 UNION ALL SELECT * FROM (SELECT Staff.[StaffID], Staff.[StaffName], Staff.[PhoneNo], Staff.[Photo], Staff.[EmpmType], Staff.[AcadStaff], Designation.[DesignationName], Section.[SectionName], Groups.[GroupName], Staff.[InternetAddr], ROW_NUMBER() OVER(ORDER BY Designation.[SortingOrder]) AS Rownum FROM Staff LEFT JOIN Designation ON Designation.[DesignationID] = Staff.[DesignationID] LEFT JOIN Groups ON Groups.[GroupID] = Staff.[GroupID] LEFT JOIN Section ON Section.[SectionID] = Staff.[SectionID] WHERE (Staff.[StaffName] IS NULL)) AS test2;" 
       DeleteCommand="DELETE FROM Staff Where StaffID=@DSid" DataSourceMode="DataSet" CacheKeyDependency="MyCacheDependency"> 
       <DeleteParameters> 
        <asp:Parameter Name="DSid" Type="String" /> 
       </DeleteParameters> 
      </asp:SqlDataSource> 
      <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" CellPadding="4" HeaderStyle-HorizontalAlign="Left" DataKeyNames="StaffID" CssClass="table table-striped table-condensed" ForeColor="#333333" GridLines="None" DataSourceID="SqlDataSource1" OnSelectedIndexChanged="GridView1_SelectedIndexChanged" AllowPaging="True" PageSize="8" OnPageIndexChanging="GridView1_PageIndexChanging"> 
       <AlternatingRowStyle BackColor="White" ForeColor="#284775" /> 
       <Columns> 
        <asp:TemplateField ShowHeader="false"> 
         <ItemTemplate> 
          <asp:Image ID="Image1" Height="50px" Width="40px" runat="server" ImageUrl='<%# Eval("Photo", "~/StaffPhoto/{0}") %>' /> 
         </ItemTemplate> 
        </asp:TemplateField> 
        <asp:BoundField DataField="StaffID" HeaderText="Staff ID" ReadOnly="True" SortExpression="StaffID"/> 
        <asp:BoundField DataField="StaffName" HeaderText="Staff Name" SortExpression="StaffName"/> 
        <asp:BoundField DataField="PhoneNo" HeaderText="Ext. No" SortExpression="PhoneNo" /> 
        <asp:BoundField DataField="DesignationName" HeaderText="Designation Name" SortExpression="DesignationName" /> 
        <asp:BoundField DataField="InternetAddr" HeaderText="Email" SortExpression="InternetAddr" /> 
        <%--   <asp:BoundField DataField="EmpmType" HeaderText="Employment Type" /> 
     <asp:BoundField DataField="AcadStaff" HeaderText="Staff Type" />--%> 
        <asp:CommandField ShowSelectButton="True" /> 
        <asp:TemplateField ShowHeader="False"> 
         <ItemTemplate> 
          <asp:LinkButton ID="btndelete" runat="server" OnClick="btndelete_Click" Text="Delete" CommandName="Delete" 
           ForeColor="Black" /> 

         </ItemTemplate> 
        </asp:TemplateField> 
        <asp:TemplateField ShowHeader="False"> 
         <ItemTemplate> 
          <asp:LinkButton runat="server" ID="btnUp" OnClick="Update_Click" ForeColor="Black">Update</asp:LinkButton> 
         </ItemTemplate> 
        </asp:TemplateField> 

       </Columns> 
       <EditRowStyle BackColor="#999999" /> 
       <HeaderStyle BackColor="white" Font-Bold="false" ForeColor="black" /> 
       <PagerStyle HorizontalAlign="Center" CssClass="pagination-ys" /> 
       <RowStyle BackColor="white" ForeColor="#333333" /> 
       <FooterStyle BackColor="white" ForeColor="black" /> 
       <SelectedRowStyle BackColor="#E2DED6" ForeColor="#333333" /> 
       <SortedAscendingCellStyle BackColor="#E9E7E2" /> 
       <SortedAscendingHeaderStyle BackColor="#506C8C" /> 
       <SortedDescendingCellStyle BackColor="#FFFDF8" /> 
       <SortedDescendingHeaderStyle BackColor="#6F8DAE" /> 
       <EmptyDataTemplate> 
        <span style="color: red">* No Data Found.</span> 
       </EmptyDataTemplate> 
      </asp:GridView> 
     </div> 
     <div style="clear: both; height: 50px;"> 
     </div> 
    </ContentTemplate> 

</asp:UpdatePanel> 

код позади для PageLoad связывания

protected void Page_Load(object sender, EventArgs e) 
    { 
     if (!Page.IsPostBack) 
     { 

      GridView1.SelectedIndex = -1; 
      GridView1.AllowPaging = false; 
     } 
     GridView1.DataBind(); 
     GridView1.AllowPaging = true; 
    } 

On Выберите для строки

protected void GridView1_SelectedIndexChanged(object sender, EventArgs e) 
    { 
     string subgpID = GridView1.SelectedRow.Cells[1].Text; 
     BllStaff bs = new BllStaff(); 
     string sName = bs.GetStaffName(subgpID); 
     if (sName == "") 
     { 
      ScriptManager.RegisterStartupScript(this, GetType(), "alert", "StaffErrorMessage();", true); 
     } 
     else 
     { 
      Response.Redirect("StaffListDetails.aspx?staffid=" + subgpID); 
     } 
    } 

StaffUpdate Страница CS

public partial class StaffUpdate : System.Web.UI.Page 
{ 
    protected void Page_Load(object sender, EventArgs e) 
    { 
     if (string.IsNullOrEmpty(Session["UT"] as string)) 
     { 
      Response.Redirect("~/LoginPage.aspx"); 
     } 
     lbMessage.Text = ""; 

     string ID = Request.QueryString["staffid"].ToString(); 

     lblSID.Text = ID; 
     tbStaffID.Text = ID; 
     if (Session["UT"].ToString() == "Admin") 
     { 
      ddlAT.Items.Remove("Admin"); 
     } 
     if (ID == Session["StaffID"].ToString()) 
     { 
      if (Session["UT"].ToString() == "Power Admin") 
      { 
       //Button1.Visible = true; 
       OPassword.Attributes.Remove("style"); 
       NPassword.Attributes.Remove("style"); 
       NCPassword.Attributes.Remove("style"); 
      } 
     } 
     tbStaffID.ReadOnly = true; 
     if (!Page.IsPostBack) 
     { 
      if (Session["UT"].ToString() != "Power Admin") 
      { 
       if (Session["UT"].ToString() != "Admin") 
       { 
        ddlAT.Items.Insert(0, new ListItem("Staff", "Staff")); 
        ddlAT.Enabled = false; 
       } 
       else 
       { 
        if (ID == Session["StaffID"].ToString()) { ddlAT.Items.Insert(0, new ListItem("Admin", "Admin")); } 
        else 
        { 
         ddlAT.Items.Insert(0, new ListItem("Staff", "Staff")); 
         ddlAT.Enabled = false; 
        } 
       } 
      } 
      else 
      { 
       if (ID == Session["StaffID"].ToString()) 
       { 
        ddlAT.Items.Insert(0, new ListItem("Power Admin", "Power Admin")); 
        ddlAT.Enabled = false; 
       } 
       else 
       { 
        BllAccount utAc = new BllAccount(); 
        string utAccount = utAc.GetStaffUT(ID); 
        if (utAccount == "Admin") 
        { 
         ddlAT.Items.Insert(0, new ListItem("Admin", "Admin")); 
         ddlAT.Items.Insert(1, new ListItem("Staff", "Staff")); 
        } 
        else 
        { 
         ddlAT.Items.Insert(0, new ListItem("Staff", "Staff")); 
         ddlAT.Items.Insert(1, new ListItem("Admin", "Admin")); 
        } 
       } 
      } 
     } 




    } 
    private string Encrypt(string clearText) 
    { 
     string EncryptionKey = "MAKV2SPBNI99212"; 
     byte[] clearBytes = Encoding.Unicode.GetBytes(clearText); 
     using (Aes encryptor = Aes.Create()) 
     { 
      Rfc2898DeriveBytes pdb = new Rfc2898DeriveBytes(EncryptionKey, new byte[] { 0x49, 0x76, 0x61, 0x6e, 0x20, 0x4d, 0x65, 0x64, 0x76, 0x65, 0x64, 0x65, 0x76 }); 
      encryptor.Key = pdb.GetBytes(32); 
      encryptor.IV = pdb.GetBytes(16); 
      using (MemoryStream ms = new MemoryStream()) 
      { 
       using (CryptoStream cs = new CryptoStream(ms, encryptor.CreateEncryptor(), CryptoStreamMode.Write)) 
       { 
        cs.Write(clearBytes, 0, clearBytes.Length); 
        cs.Close(); 
       } 
       clearText = Convert.ToBase64String(ms.ToArray()); 
      } 
     } 
     return clearText; 
    } 

    protected void Button2_Click(object sender, EventArgs e) 
    { 
     string SID = tbStaffID.Text; 
     string oldP = Encrypt(tbPasswordOld.Text); 
     string newP = tbPasswordNewC.Text; 
     string ut = ddlAT.SelectedValue; 
     string fileName = ""; 
     string OID = Request.QueryString["Staffid"].ToString(); 
     if (tbStaffID.Text != "") 
     { 
      if (this.ImageFileUpload.HasFile) 
      { 
       if (tbPasswordNewC.Text != "" || tbPasswordOld.Text != "") 
       { //update id, password, photo and UT 
        //if (RegularExpressionValidator2.IsValid) 
        if (tbPasswordNewC.Text != "" && tbPasswordOld.Text != "") 
        { 
         string strsql = "select * FROM Account WHERE UserID='" + SID + "' and Password='" + oldP + "'"; 
         DataTable dt = sql.ExecTable(strsql); 
         if (dt.Rows.Count > 0) 
         { 
          try 
          { 
           string[] validFileTypes = { "bmp", "gif", "png", "jpg", "jpeg" }; 
           string ext = System.IO.Path.GetExtension(ImageFileUpload.PostedFile.FileName).ToLower(); 
           bool isValidFile = false; 
           for (int i = 0; i < validFileTypes.Length; i++) 
           { 
            if (ext == "." + validFileTypes[i]) 
            { 
             isValidFile = true; 
             break; 
            } 
           } 
           if (!isValidFile) 
           { 
            lbMessage.ForeColor = System.Drawing.Color.Red; 
            lbMessage.Text = "* Invalid File. Please upload a File with extension " + 
                string.Join(", ", validFileTypes); 
           } 
           else 
           { 
            FileInfo fi = new FileInfo(ImageFileUpload.FileName); 
            string extion = fi.Extension; 
            Session["fileEx"] = extion; 
            fileName = "Ori" + SID + extion; 
            //create instance for image class 
            System.Drawing.Image myimg = default(System.Drawing.Image); 
            //get uploaded image input stream 
            using (myimg = System.Drawing.Image.FromStream(ImageFileUpload.PostedFile.InputStream)) 
            { 
             //resize it using thumbnailimage method 
             int width = myimg.Width; 
             int height = myimg.Height; 
             double bthumbWidth = 300 * width/height; 
             int thumbWidth = Convert.ToInt32(bthumbWidth); 
             myimg = myimg.GetThumbnailImage(thumbWidth, 300, null, IntPtr.Zero); 
             MemoryStream str = new MemoryStream(); 
             //Save it in the server images folder 
             myimg.Save(Server.MapPath("~\\StaffPhoto\\Ori\\" + fileName), myimg.RawFormat); 
             myimg.Dispose(); 
             //string strFilePath = Server.MapPath("~/StaffPhoto/") + "\\" + fileName; 
             //this.ImageFileUpload.SaveAs(strFilePath); 
             imgUpload.ImageUrl = "~/StaffPhoto/Ori/" + fileName; 
            } 
            panCrop.Visible = true; 
            string up = "a"; 
            Session["UpdateP"] = up; 
           } 
          } 
          catch (Exception ex) 
          { 
           lbMessage.ForeColor = System.Drawing.Color.Red; 
           lbMessage.Text = ex.Message + "* The Photo has failed to update. Please try again later!"; 
          } 
         } 
         else 
         { 
          lbMessage.Text = "* Password Wrong!"; 
         } 
        } 
        else 
        { 
         lbMessage.Text = "* Both password field must fill in!"; 
        } 
       } 
       else //update photo, id and UT 
       { 
        try 
        { 
         string[] validFileTypes = { "bmp", "gif", "png", "jpg", "jpeg", "ico", "jpe" }; 
         string ext = System.IO.Path.GetExtension(ImageFileUpload.PostedFile.FileName).ToLower(); 
         bool isValidFile = false; 
         for (int i = 0; i < validFileTypes.Length; i++) 
         { 
          if (ext == "." + validFileTypes[i]) 
          { 
           isValidFile = true; 
           break; 
          } 
         } 
         if (!isValidFile) 
         { 
          lbMessage.ForeColor = System.Drawing.Color.Red; 
          lbMessage.Text = "* Invalid File. Please upload a File with extension " + 
              string.Join(", ", validFileTypes); 
         } 
         else 
         { 
          FileInfo fi = new FileInfo(ImageFileUpload.FileName); 
          string extion = fi.Extension; 
          Session["fileEx"] = extion; 
          fileName = "Ori" + SID + extion; 
          //create instance for image class 
          System.Drawing.Image myimg = default(System.Drawing.Image); 
          //get uploaded image input stream 
          using (myimg = System.Drawing.Image.FromStream(ImageFileUpload.PostedFile.InputStream)) 
          { 
           //resize it using thumbnailimage method 
           int width = myimg.Width; 
           int height = myimg.Height; 
           double bthumbWidth = 300 * width/height; 
           int thumbWidth = Convert.ToInt32(bthumbWidth); 
           myimg = myimg.GetThumbnailImage(thumbWidth, 300, null, IntPtr.Zero); 
           MemoryStream str = new MemoryStream(); 
           //Save it in the server images folder 
           myimg.Save(Server.MapPath("~\\StaffPhoto\\Ori\\" + fileName), myimg.RawFormat); 
           myimg.Dispose(); 
           //string strFilePath = Server.MapPath("~/StaffPhoto/") + "\\" + fileName; 
           //this.ImageFileUpload.SaveAs(strFilePath); 
           imgUpload.ImageUrl = "~/StaffPhoto/Ori/" + fileName; 
          } 
          panCrop.Visible = true; 
          string up = "b"; 
          Session["UpdateP"] = up; 
         } 
        } 
        catch (Exception ex) 
        { 
         lbMessage.ForeColor = System.Drawing.Color.Red; 
         lbMessage.Text = ex.Message + "* The Photo has failed to update. Please try again later!"; 
        } 
       } 
      } 
      else //update password, id and UT 
      { 
       if (tbPasswordNewC.Text != "" || tbPasswordOld.Text != "") 
       { //update id, password, photo and UT 
        //if (RegularExpressionValidator2.IsValid) 
        if (tbPasswordNewC.Text != "" && tbPasswordOld.Text != "") 
        { 
         string strsql = "select * FROM Account WHERE UserID='" + SID + "' and Password='" + oldP + "'"; 
         DataTable dt = sql.ExecTable(strsql); 
         if (dt.Rows.Count > 0) 
         { 
          string upMessage = "You are trying to update the information for staff: " + SID; 
          string no = "3"; 
          Response.Redirect("AlertUpdate.aspx?MessageNO=" + no + "&UpdateMessage=" + upMessage + "&UpdateStaffid=" + SID + "&fileN=" + fileName + "&NewPass=" + newP + "&UserT=" + ut); 

         } 
         else 
         { 
          lbMessage.Text = "* Password Wrong!"; 
         } 
        } 
        else 
        { 
         lbMessage.Text = "* Both password field must fill in!"; 
        } 
       } 
       else 
       { 
        string upMessage = "You are trying to update the information for staff: " + SID; 
        string no = "4"; 
        Response.Redirect("AlertUpdate.aspx?MessageNO=" + no + "&UpdateMessage=" + upMessage + "&UpdateStaffid=" + SID + "&fileN=" + fileName + "&NewPass=" + newP + "&UserT=" + ut); 

       } 
      } 

     } 
     else 
     { 
      lbMessage.Text = "* Staff ID must be provided"; 
     } 
    } 

    private void CheckName() 
    { 
     string SID = tbStaffID.Text; 
     BllStaff bs = new BllStaff(); 
     string sName = bs.GetStaffName(SID); 
     if (sName == "") 
     { 
      Response.Redirect("StaffListAdSearch.aspx"); 
     } 
     else 
     { 
      Response.Redirect("StaffListDetails.aspx?staffid=" + SID); 
     } 
    } 
    protected void btnUpNewP_Click(object sender, EventArgs e) 
    { 
     uploadNewP.Visible = true; 
     uploadNewPD.Visible = false; 
    } 

    protected void Button1_Click(object sender, EventArgs e) 
    { 
     string staffid = tbStaffID.Text; 
     string role = ddlAT.SelectedValue; 
     Response.Redirect("AlertUSuc.aspx?staffid=" + staffid + "&role=" + role); 
    } 

    protected void btnCrop_Click(object sender, EventArgs e) 
    { 
     string SID = tbStaffID.Text; 
     string oldP = Encrypt(tbPasswordOld.Text); 
     string newP = tbPasswordNewC.Text; 
     string ut = ddlAT.SelectedValue; 
     string fileName = Path.GetFileName(imgUpload.ImageUrl); 
     string filePath = Path.Combine(Server.MapPath("~/StaffPhoto/Ori"), fileName); 
     string cropFileName = ""; 
     string cropFilePath = ""; 
     if (File.Exists(filePath)) 
     { 
      System.Drawing.Image orgImg = System.Drawing.Image.FromFile(filePath); 
      System.Drawing.Rectangle CropArea = new System.Drawing.Rectangle(
       Convert.ToInt32(X.Value), 
       Convert.ToInt32(Y.Value), 
       Convert.ToInt32(W.Value), 
       Convert.ToInt32(H.Value)); 
      try 
      { 
       Bitmap bitMap = new Bitmap(CropArea.Width, CropArea.Height); 
       using (Graphics g = Graphics.FromImage(bitMap)) 
       { 
        g.DrawImage(orgImg, new System.Drawing.Rectangle(0, 0, bitMap.Width, bitMap.Height), CropArea, GraphicsUnit.Pixel); 

        cropFileName = SID + Session["fileEx"]; 
        cropFilePath = Path.Combine(Server.MapPath("~/StaffPhoto"), cropFileName); 
        bitMap.Save(cropFilePath); 
        bitMap.Dispose(); 
        string At = ddlAT.SelectedValue; 
        if (Session["UpdateP"].ToString() == "a") 
        { 
         string upMessage = "You are trying to update the information for staff: " + SID; 
         string no = "1"; 
         Response.Redirect("AlertUpdate.aspx?MessageNO=" + no + "&UpdateMessage=" + upMessage + "&UpdateStaffid=" + SID + "&fileN=" + cropFileName + "&NewPass=" + newP + "&UserT=" + ut + "&DelFile=" + fileName, false); 
        } 
        else if (Session["UpdateP"].ToString() == "b") 
        { 
         string upMessage = "You are trying to update the information for staff: " + SID; 
         string no = "2"; 
         Response.Redirect("AlertUpdate.aspx?MessageNO=" + no + "&UpdateMessage=" + upMessage + "&UpdateStaffid=" + SID + "&fileN=" + cropFileName + "&NewPass=" + newP + "&UserT=" + ut + "&DelFile=" + fileName, false); 
        } 
        g.Dispose(); 
       } 
      } 
      catch (Exception ex) 
      { 
       lbMessage.Text = ex.Message; 
      } 
      finally { 
       orgImg.Dispose(); 
      } 
     } 

    } 
} 

AlertUpdate код За образец

string strsql = "select UserType FROM Account WHERE UserID='" + OID + "'"; 
       DataTable dt = sql.ExecTable(strsql); 
       if (dt.Rows.Count > 0) 
       { 
        uStaffA.UpdateAccountbaseOnStaffID(OID, OID, ut); 
       } 

Updateaccountbaseonstaffid

public int UpdateAccountbaseOnStaffID(string staffid, string NStaffId, string ut) 
    { 
     StringBuilder sql; 
     SqlCommand sqlCmd; 
     int result = 0; 
     //int newOrderId = 0; 
     // create order header 
     SqlConnection conn = dbConn.GetConnection(); 
     sql = new StringBuilder(); 
     sql.AppendLine("UPDATE Account"); 
     sql.AppendLine("SET UserID=@Nid, StaffID=@Nid, UserType=@UserType where StaffID=@Oid"); 

     try 
     { 
      conn.Open(); 

      sqlCmd = new SqlCommand(sql.ToString(), conn); 

      sqlCmd.Parameters.AddWithValue("@Oid", staffid); 
      sqlCmd.Parameters.AddWithValue("@Nid", NStaffId); 
      sqlCmd.Parameters.AddWithValue("@UserType", ut); 

      result = sqlCmd.ExecuteNonQuery(); 
     } 
     catch (Exception ex) 
     { 
      errMsg = ex.Message; 
     } 
     finally 
     { 
      conn.Close(); 
     } 

     return result; 

    } 

AlertUpdateSuc

public partial class AlertUpdateSuc : System.Web.UI.Page 
{ 
    protected void Page_Load(object sender, EventArgs e) 
    { 

    } 

    protected void Button1_Click(object sender, EventArgs e) 
    { 
     if (Request.QueryString["MesNo"].ToString() == "1") 
     { 
      Session.Clear(); 
      Response.Redirect("LoginPage.aspx"); 
     } 
     else if (Request.QueryString["MesNo"].ToString() == "2") 
     { 
      Response.Redirect("StaffListAdSearch.aspx"); 
     } 

    } 
} 

Короче говоря, даже если обновления фото правильно, старая фотография все еще отображается, пока я не обновите страницу.

Любые идеи будут полезны! Спасибо!

Answer 1

Оказалось, для правильного отображения вашей фотографии, вам необходимо обновить URL-адрес изображения.

Однако, поскольку наш URL-адрес изображения никогда не меняется, мне нужно было добавить некоторые данные в URL-адрес, чтобы он стал уникальным и корректно обновлялся.

protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e) 
    { 
     if (e.Row.RowType == DataControlRowType.DataRow) 
     { 
      Image img = e.Row.FindControl("Image1") as Image; 
      string url = img.ImageUrl; 
      string modified = url + "?time=" + DateTime.Now.ToString(); 
      img.ImageUrl = modified; 
     } 
    } 

Выполняя то, что я сделал выше, изображение в GridView будет обновлено. Это работает для DetailsView, а также, просто делать это таким образом:

protected void ViewEmployeeDetails_DataBound(object sender, EventArgs e) 
    { 
     Image img = ViewEmployeeDetails.FindControl("Image1") as Image; 
     string url = img.ImageUrl; 
     string modified = url + "?time=" + DateTime.Now.ToString(); 
     img.ImageUrl = modified; 
    } 

Answer 2

Если вы обновляете изображение, это не означает, что ваше gridview также необходимо обновить. Ничто не будет выполнено само собой. Вы должны выполнить команду для выполнения. После обновления вашего изображения вы должны вызвать перемотку своего gridview.