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I Can't use a FileUpload control in a UpdatePanel (Ajax) ?

Posted on 2007-04-05
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Last Modified: 2013-11-26
I Can't use a FileUpload control in a UpdatePanel (Ajax) ?

This structure don’t have problems.

>          [ MasterPage [ ContentPlaceHolder [ UserControl [ FileUpload ] ] ] ]

But I have this structure:

>          [ MasterPage [ ContentPlaceHolder [ UpdatePanel [ UserControl [ FileUpload ] ] ] ]


With this code I have the error: Object reference not set to an instance of an object
>          Dim uploadImage As System.Drawing.Image
>          Dim Temp As New FileUpload
>          Temp = FileUpload1
>          uploadImage = System.Drawing.Image.FromStream(Temp.PostedFile.InputStream)

I try
FindeControl(“FileUpLoad1”)
UpdatePanel.FindeControl(“FileUpLoad1”)
UserControl.FindeControl(“FileUpLoad1”)
FindControl(“UpdatePanel”).FindeControl(“FileUpLoad1”)
FindControl(“UserControl”).FindeControl(“FileUpLoad1”)

ETC !!!...

But nothing…

Note: ASP.NET, VB.NET, VS2005 and Ajax 1.0
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Comment
Question by:darcosys
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15 Comments
 
LVL 24

Expert Comment

by:Jeff Certain
ID: 18859129
You're likely running into an issue with the naming of nested controls. Try:

FindControl(FileUpload1.ClientId)
0
 
LVL 1

Author Comment

by:darcosys
ID: 18859232
Nop :(

The same error !!!

>      Dim uploadImage As System.Drawing.Image
>      Dim Temp As New FileUpload
>      Temp = FindControl(FileUpload1.ClientID)
>      uploadImage = System.Drawing.Image.FromStream(Temp.PostedFile.InputStream)
0
 
LVL 24

Expert Comment

by:Jeff Certain
ID: 18859263
Might be UniqueId instead of ClientId... I can never remeber which to use. And you may have to replace $ with _ or vice-versa.

The easiest way to deal with this is to run your page, look at the source code, find the control you're interested in and note it's name. Then put a breakpoint on the Temp = line... check to see what FileUpload1.ClientId and FileUpload1.UniqueId are...
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LVL 1

Author Comment

by:darcosys
ID: 18859850
ClientID      "ctl00_ContentPlaceHolder1_ControlUpLoad1_FileUpload1"      String
UniqueID      "ctl00$ContentPlaceHolder1$ControlUpLoad1$FileUpload1"      String

:( ???
0
 
LVL 24

Expert Comment

by:Jeff Certain
ID: 18859878
What's the control name in the web page source? (That is.. run the app, surf to the page, right-click >> view source... this will get you the HTML)
0
 
LVL 1

Author Comment

by:darcosys
ID: 18859917
<input type="file" name="ctl00$ContentPlaceHolder1$ControlUpLoad1$FileUpload1" id="ctl00_ContentPlaceHolder1_ControlUpLoad1_FileUpload1" class="TextBox" style="width:340px;" />
0
 
LVL 24

Expert Comment

by:Jeff Certain
ID: 18859932
So... FindControl(FileUpload1.UniqueID) should get the control.

HOWEVER.... why don't you just refer to it as FileUpload1 on the server side?
Dim uploadImage As System.Drawing.Image = System.Drawing.Image.FromStream(Fileupload1.PostedFile.InputStream)
0
 
LVL 1

Author Comment

by:darcosys
ID: 18859982
UniqueID and ClientID Don't work

HOWEVER.... why don't you just refer to it as FileUpload1 on the server side? ...   It was my first attempt
0
 
LVL 24

Expert Comment

by:Jeff Certain
ID: 18860021
Are you calling FindControl on the page or the user control? You need to ask the parent container for the control IIRC.

What about UserControl.FileUpload1 on the server side?
0
 
LVL 1

Author Comment

by:darcosys
ID: 18860061
The problem is this...
The UsuerContro it's on the server but Ajax make noise.
If I Put the UserControl on a free Ajax page works perfect.
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LVL 1

Author Comment

by:darcosys
ID: 18860113
I call the FindControl from de UserControl on the server-side
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LVL 24

Expert Comment

by:Jeff Certain
ID: 18860251
I'm out of suggestions then...
0
 
LVL 1

Author Comment

by:darcosys
ID: 18860260
On the webpage, The same UserControl out of the UpdatePanel works but in the UpdatePanel don't works.
0
 
LVL 6

Accepted Solution

by:
carmodyk earned 500 total points
ID: 18947565
Read this article, see if this helps:
http://www.codeproject.com/useritems/simpleajaxupload.asp
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Author Comment

by:darcosys
ID: 18948623
Tk
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