Failed to load viewstate HttpException after calling FormView.UpdateItem(true);

[J055]

Hi

I need some help with this one. If I add this LinkButton Command event I get
an 'System.Web.HttpException: Failed to load viewstate' on the second
postback. It only occurs when FormView1.UpdateItem(true) is called. The page
posts back OK. When I do a second PostBack I get the error.

protected void LinkButtonPrevNext_Command(object sender,
CommandEventArgs e)
{
if (FormView1.CurrentMode == FormViewMode.Edit)
{
FormView1.UpdateItem(true);
}
//...other bits
}

As far as I know I am not loading any Controls dynamically. I'm finding it
almost impossible to debug and find out why the controls are different.

What's the best way to isolate the problem?

Thanks
Andrew

 

[Steven Cheng[MSFT]]

Hello Andrew,

From your description, you're getting "System.Web.HttpException: Failed to
load viewstate...." exception when manually use a button to trigger the
FormView's UpdateItem command, correct?

According to the code logic you mentioned, I have performed some simple
test on my local side and it seems a very simple and typical FormView
editing/updating webform can not quite repro the exact error behavior. My
test result is as below:

I use a FormView to edit and update a very simple table in SQL Server, the
autogenerated edit/update interface(inside formview works well).

And then I put a button on the webform(out side of the formview) and add
code to manually update the FormView item:

protected void btnOutUpdate_Click(object sender, EventArgs e)
{
if (FormView1.CurrentMode == FormViewMode.Edit)
{
FormView1.UpdateItem(true);
}
}

it also works without any problem. Therefore, I think the problem is
likely specific to the data table or anything else on the webform. I
suggest you try simplify the page step by step to isolate the cause.

If you have any new finding or anything we can help, please feel free to
post here.

Sincerely,

Steven Cheng

Microsoft MSDN Online Support Lead



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[J055]

Hi Steven

I solved the problem by adding FormView1.DataBind below the UpdateItem
method. My code creates and event when the UpdateItem occurs to tell the
Parent page to switch to another View in a MultiView control. If I don't
change the view then the error doesn't occur.

The MultiView control contains 4 views with their own user control. I'm
still not sure why DataBinding would solve the problem and why the error
occurs when the MultiView.ActiveViewIndex is changed.

Thanks
Andrew