What is the life cycle of an ASP.NET file upload on code behind?
I would like to know what events get executed (if any) after a user has selected to submit a file for upload on an ASP.NET page.
Would I need to tweak anything at the IIS level?
Should the page life cycle events be triggered when the user uploads a file?
I see different behaviour on my 开发者_如何学JAVAdevelopment server from Visual Studio in regards to the IIS server I deploy to:
on the development server, the life cycle events get triggered when a file gets selected, on the deployed server they don't..
What classes would I need to override, what web.config
settings should I change, in order to tweak the default behaviour of the upload?
The problem I am having, is finding documentation on how to have code executed before the file gets uploaded, but after a file got selected.
P.S. this is related to a previous question of mine here, but approached in a very different way in the hopes of understanding the whole upload process, so I thought it's a different question all together.
No, it has no event for file upload(maybe on .net 4)
what I did was a class that derives from the upload object and on OnLoad event something like this:
public event EventHandler OnUpload;
protected void OnLoad(...){
if (this.HasFile && this.OnUpload != null)
this.OnUpload(this, EventArgs.Empty);
}
sort of that.
Joe
-- Edit: Oh, I re-read your post and you want to know when people selects a file but it is not yet sent to the server? thats javascript. Server side can't know when people select it without sending a information to the server. You can develop a WebService function that is called when the onchanged of the input has been called, but I don't know if thats a good idea. Can you use javascript for this?
try:
<asp:textbox id="t1" runat="server"/>
on code behind:
t1.Attributes.Add("onchange", "alert('it changed its value: ' + this.value);");
hope it helps.
To execute code before upload, it would have to be JavaSript code running in the browser. See my answer to a question about filtering file uploads based on type:
How to filter which files can be seen on upload dialog box?
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