Passing Value from Page to Another Page ASP.net Using VB - asp.net

Question

I simply need to copy the textbox input data to another page. i have a datagridview from Home.aspx when i select data from it. it will display the row data to the textbox. now i want to copy/pass the data to another page. how can i do that? i tried following codes but it does not work.
This is the 2ndPage Code on load_page
If Not Page.PreviousPage Is Nothing Then
Dim SourceTextBox As TextBox
SourceTextBox = CType(PreviousPage.FindControl("TextBox1"), _
TextBox)
If Not SourceTextBox Is Nothing Then
Label1.Text = SourceTextBox.Text
End If
End If

Answer 1

Ok, a truckload of issues here.
First up:
page.previouspage is ONLY available if you used
Server.Transfer("~/MyCoolWebPage.aspx")
And as general rule you don't a "server side" transfer/jump/hop to a page this way. Trying to keep this post short, but a server.Transfer() means that no real browser side jump to the page occurs - only a server side transfer. That means that the previous URL does not even change! And thus as a general rule, a jump to a page occures from a button click on a page, and that button click can be a client side (JavaScript) click, or a standard button click that executes the Response.Redirect(). However, in both cases, it really is a client side browser request. You as a general rule thus don't want to build or write a web page that "assumes" that a Server.Transfer() was how you landed on that page.
Because of the above? Well me.Page.PreviousPage is ONLY available if the page you are landing on was the RESULT of a 100% server side re-direction to a new page. And that simply not going to be the case, and thus for the vast majority of your web pages, then page.Previouspage will be null, and of ZERO use to you. (it's simply not available).
So, now we back to traditional means and approaches to "transfer" data to the next page.
Remember, that page is state-less. That means EVEN on the same page, all values, and variables are lost between each page load. Even a simple button click means the page will re-load, but that re-load will see all your values lost. Now most controls such as a text box, or even the gridview can and will keep what is called their state for those "round trips" when you click say on a button.
Now, in your case, no doubt you are clicking on a button, and jumping/loading to a new web page. Thus, all previous controls, data and everything you had in existance on that previous page is all gone, and lost.
So, how to pass values give this "state-less' nature of web pages?
Well, a very common way is to use parameters in the URL. However, I find them quite ugly, and users can also mess with those values. However, for really large web sites, we see the parmaters in the URL often used, and that's because the web site does not want to spent the energy, the time and even the memory and resources to keep track of say 1 million users hitting that web site.
But, there is another very common means to "save" values in what we call a round trip. That handy dandy "temp" storage system is called Session(). Now Session() should be treated as a precious and limited resource, but it is quite much how you can (and should) pass values around. The beauty of these values is they "persist" and keep their values between post-backs. And this includes jumping to another page.
So, to pass that data to the next page?
Simply stuff that data row into the session, and then in the target page, you can then get/grab/use/pull any values from that one row of data.
So right before your response.Redirect("to my 2nd page page"), you can do this:
Session("MyTextBox") = me.TextBox1.Text
Now above is fine for one text box value. But, you want to pass the whole row.
So, you can go:
Session("MyListDataRow") = MyRowOfData
Now, you don't explain how or when or where you selected the one row of data. But you can certainly shove the one row of data into session, and then show/display it on the next page.
One more SUPER DUPER WHOPPER:
If you do pull out the selected row into a datarow (as opposed to datatable, or dataset), then keep in mind that .net serializers don't support the datarow (why, I have no idea!!!). So if you using "in-memory" sessions(), then you are ok. But if you ever decide to adopt SQL based session() management, then that code will start to fail. So, either shove in a ListViewDataItem, or a datatable to pass that row of data, and not a datarow.
I would thus just not pass a "datarow" in Session() and avoid the above horrifying revelation that .net left out that data rows don't support serialization! (holy moly!!!!).
So unless you are using a server.transfer() for this, then page.previous is not valid nor available. And if you using a master page, then you have to first dig and get the master page refernce, and then the ContentPlaceHolder if you ARE using a server transfer and you thus do have use of page.PagePrevious.
Edit:
Having said all of the above? Well, if you have a click event on a listview (or datagrid) row, then a server.transfer actually is "one" of those good use cases in which you may VERY well consider a server.transfer(), since the you have full use of the listview/datagrid data in that 2nd page though use of page.PreviousPage. Just be aware that you have to pull down one more level to get at the content if you using master pages.