ASP.NET - VB.NET - Persist a GridView's dynamically chosen DataSourceID over multiple button clicks

Question

I have an app where I need to dynamically choose an SQLDataSource for a GridView so I can use 1 of 2 stored procedures, depending on who is logged into the system.

My problem is that I am using logic like this, in the button click...

If Session("SiteType") = "Type1" Then
     GridView1.DataSourceID = "SqlDataSource2"
Else
     GridView1.DataSourceID = "SqlDataSource1"
End If
GridView1.DataBind()

This happens when you click the button that reveals the panel with the gridview in it.

The user then makes changes (basically adjusting a text box on one or more liens of the grid) and then clicks "save". However, the gridview no longer knows its DataSourceID once this happens, so when I try to go through the gridview's rows - there are none.

If, in the save button's click, I put the same code, it (of course) blanks out any of the data changes I made in the form.

So, simply put - how do I dynamically choose the SqlDataSource, but only one time, so that the program then keeps that SqlDataSourceID associated with the gridview until the end of the cycle? Is this a ViewState thing? I don't totally understand ViewState...

Pardon my ignorance - I'm assuming this is kind of simple, but I just don't have a ton of .NET experience. If there is a better way, I'd be interested in hearing that as well - that said, time is of the essence so I'm kind of looking for the quick fix right now (boss is breathing down my neck.. heh).

Thanks!

Answer 1

I've done this by simply putting the option into a cookie and when I need it again pulling that option down from the cookie.

Cookies, Session and ViewState all generally work the same. They are a simple way of persisting information for a limited amount of time. You create a key, you add a value and then save the key back to what ever medium you are going to use be it a cookie, session or viewstate. When you need the value again, you just find the key in from the perstent medium, load the key/value pair and then access the value by ususally putting it back into a variable of sometype.

Good luck, and hope this helps some.

Answer 2

You need to rebind the grid on each postback because you are setting the datasource at runtime in code.

Add this to the pages load event handler:

If Page.IsPostback Then
    If Session("SiteType") = "Type1" Then
       GridView1.DataSourceID = "SqlDataSource2"
    Else
       GridView1.DataSourceID = "SqlDataSource1"
    End If
    GridView1.DataBind()
End If

Answer 3

I would just go and and save it as a session variable. Ex. Session("datasource") = myDataSource

Then you set your GridView's datasource as such: MyGridView.datasource = session("datasource") MyGridView.bind()

That should do it.

Hope this helps' David.