In my website I am uploading photos through asp:FileUpload [multiple files - images].. After uploading I am displaying them in a Panel along with a textbox to write description for the uploaded Images. Then am going to save them in database. But I am not able to find the values of the textbox or find the controls I have added to the panel when in my save event. But the images and textbox will be displayed in the panel.
My frontend code is something like this:
<form id="form1" runat="server">
<div class="transbox" id="mainbk" runat="server" style="position:absolute; top:0px; left:0px; width: 100%; height: 100%;" >
<asp:FileUpload runat="server" ID="UploadImages" style="background-color:white; position:absolute; font-family:'Palatino Linotype'; font-size:medium; top: 4px; left: 350px; right: 251px;" Width="500px" AllowMultiple="true"/>
<asp:Button runat="server" ID="uploadedFile" style="position:absolute; font-family:'Palatino Linotype'; font-size:medium; top: 4px; left: 870px; width: 112px; height: 29px;" Text="Upload" OnClick="uploadFile_Click" />
<asp:Panel ID="updtpanel" runat="server" CssClass="transbox" style="width:100%;height:100%;left:0px;top:0px;position:absolute" Visible="false">
<asp:Button ID="btnsave" runat="server" Text="Save" OnClick="btnsave_Click" Font-Bold="true" BackColor="Yellow" />
</asp:Panel>
</div>
</form>
and my backend code is something like this:
protected void uploadFile_Click(object sender, EventArgs e)
{
if (UploadImages.HasFiles)
{
int tid = 0;
string fileExt = Path.GetExtension(UploadImages.FileName).ToLower();
if (fileExt == ".jpeg" || fileExt == ".png" || fileExt == ".jpg" || fileExt == ".bmp")
{
HtmlGenericControl dh = new HtmlGenericControl("div");
dh.Attributes.Add("class", "head");
dh.InnerText = "Write Description";
updtpanel.Controls.Add(dh);
HtmlGenericControl dload;
foreach (HttpPostedFile uploadedFile in UploadImages.PostedFiles)
{
tid = tid + 1;
textid = "txt" + tid;
Image img = new Image();
TextBox ta = new TextBox();
ta.TextMode = TextBoxMode.MultiLine;
filepath = Server.MapPath("~/Images/Gallery/" + uploadedFile.FileName);
uploadedFile.SaveAs(filepath);
newpath = "../Images/Gallery/" + uploadedFile.FileName;
try
{
dload = new HtmlGenericControl("div");
updtpanel.Visible = true;
dload.Attributes.Add("class", "dataload");
dload.Attributes.Add("runat", "server");
dload.ID = "ind" + tid;
img.CssClass = "loadimg";
img.ImageUrl = newpath.ToString();
img.ID = "img"+tid;
img.Attributes.Add("runat", "server");
ta.Attributes.Add("class", "txtdes");
ta.ID = textid;
ta.Attributes.Add("runat", "server");
dload.Controls.Add(img);
dload.Controls.Add(ta);
updtpanel.Controls.Add(dload);
}
catch (Exception ex)
{
Response.Write(ex.Message);
}
}
}
else
{
Page.ClientScript.RegisterStartupScript(GetType(), "msgbox", "alert('Please Select only Image Files!!');", true);
}
}
else
{
Page.ClientScript.RegisterStartupScript(GetType(), "msgbox", "alert('Please Select a File First!!');", true);
}
}
protected void btnsave_Click(object sender, EventArgs e)
{
foreach (Control c in updtpanel.Controls)
{
cnt1 += 1;
HtmlGenericControl div = ((HtmlGenericControl)updtpanel.FindControl("ind"+cnt1.ToString()));
foreach (Control nc in div.Controls)
{
string str = "";
string iurl = "";
TextBox txt = (TextBox)div.FindControl("txt" + cnt1.ToString());
Image img = (Image)div.FindControl("img" + cnt1.ToString());
str = txt.Text;
iurl = img.ImageUrl;
id += 1;
string Insert = "Insert into slider (slid,slurl,slalt) values (@id,@IMAGE_PATH,@alter)";
SqlCommand cmd = new SqlCommand(Insert, con);
cmd.Parameters.AddWithValue("@IMAGE_PATH", iurl);
cmd.Parameters.AddWithValue("@id", id);
cmd.Parameters.AddWithValue("@alter", str);
try
{
con.Open();
cmd.ExecuteNonQuery();
con.Close();
}
catch (Exception e1)
{
Response.Write(e1.Message);
}
}
}
updtpanel.Visible = false;
}
But its giving an error while saving which says object reference not set to an instance of the object after Findcontrol in save click event. Where I am going wrong. I am really working this from past 3 days but still not able to get it. Please show me a way out of this.
Is there anything else I need to add to this? I came across some site where some of them said that controls need to be recreated in Page_Load after postback. But when I am creating controls in an event How can I recreate them back in Page_Load.
