Hello all,
I am trying to pass page properties between two pages and the first page
contains a datagrid loaded dynamically from a data access and the second
page needs one item from the query string and the provided properties from
the previous page. I am getting an error from the second Page_Load method
during the loading of the properties of the previous page. The error is
'Specified cast is not valid' which is consistant with an error that occurs
when you do not use Server.Transfer( ... ) to access the second page ( I
think this is the reason for the error ). My question is do you think this
is the source of my error and if so is there a way to control how the page
is transfered? I am developing using C# as code behind to aspx.

Thanks...

Hi Jason,

Without more detailed info, it's hard to say what's wrong
in you application.

Personally, I don't think it will cause trouble to pass
any data to the second page without using Server.Transfer.

Elton Wang
elton_w***@hotmail.com

the first page
and the second
provided properties from
page. The error is
error that occurs
second page ( I
do you think this
control how the page
Show quoteHide quote

Here is an example of my code and error location.
The full code is much to large to post so here is an abstract.

Page1.aspx.cs

public string Property1
{
   get
   {
      return prop1;
   }
}

public string Property2
{
   get
   {
      return prop2;
   }
}

page1.aspx

populate a datagrid via data access and 
<Columns>
   <asp:HyperLinkColumn DataNavigateUrlField="LocationID"
            DataNavigateUrlFormatString="page2.aspx?ID={0}"
DataTextField="LocationName" HeaderText="Store">     
         <HeaderStyle Font-Size="11px" Font-Bold="True"></HeaderStyle>
     <ItemStyle Font-Size="11px" Wrap="False"
            HorizontalAlign="Left"CssClass="blueLink"
            VerticalAlign="Top"></ItemStyle>   
       </asp:HyperLinkColumn>

bla bla....
</Columns>

page2.aspx.cs
//define prop1 and prop2 as strings

private void Page_Load
(object sender, System.EventArgs e)
{
   //create instance of source web form
   page1 p1;

   //get reference to current handler instance
   p1 = ( page1 )Context.Handler;           <-------Here is where the error
ocurrs
   prop1 = p1.Property1;            
   prop2 = p1.Property2;
}

I hope this is enough to work with.

First of all, you should understand the web application is
completely different from windows application. It's so
called stateless that means once you move from one page to
another page the first page is disappeared. You can't
refer to it and of course, can't get any data from it.
When you go back to the first page, it actually re-
initializes a new instance.

In order to transfer data between pages within an
application, you can use ApplicationState, SeesionState,
ViewState, or Cookie to save data in these objects, and
then share the data in different pages. In your case, you
can use SessionState to save data in page1. Then in page2
retrieve the data from SessionState.

To save data to SessionState:
Session("keyName") = obj;

To retrieve data from SessionState:
ObjectType obj = (ObjectType)Session("keyName"); 

HTH

Elton Wang


Show quoteHide quoteBold="True"></HeaderStyle>
Show quoteHide quoteis where the error
Show quoteHide quote

I want to refer you to a page that explains what I am trying to do here and
it is located @ http://www.dotnetbips.com/displayarticle.aspx?id=79
I work for a large company and we have rules in place governing what I can
and cannot use such as session state state management. We have to use a
component that requires the use of a database and for what I am doing that
is much more overhead then I want at this time, but if I have to I will use
it. I hope this explains my purpose.

Of course, it's fine if you use query string to pass
parameters to second page.

In your case, you can use

page2.aspx?prop1=p1Value&prop2=p2Value

to access page2 from page1.

In page2, use

string p1 = Request.QueryString.Get("prop1");
string p2 = Request.QueryString.Get("prop2");

to retrieve those values.

HTH

Elton Wang


trying to do here and
http://www.dotnetbips.com/displayarticle.aspx?id=79
governing what I can
have to use a
what I am doing that
have to I will use
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