从asp.net中的上一页读取控件

Question

I have Page1.aspx containing

Name: <asp:TextBox ID="txt1" runat="server" />

Page2.aspx tries to access its contents by

   TextBox txt2 = (TextBox)PreviousPage.FindControl("txt1");

However I end up getting an Object reference not set to instance of an object exception

Answer 1

I've used PreviousPage before and have had success with this snippet of code I found elsewhere online (Can't remember where I found it!)

So..

Option 1:

On your first page you have your button that takes you to the second page, you need to set the PostBackUrl property to the new page url:

<asp:Button ID="button1" Runat="server" Text="submit" PostBackUrl="~/Page2.aspx" />

( This is presuming that your 1st page is a form that redirects to your Page2.aspx )

Then in the new page's code behind you need to write something along the lines of this:

public void page_load()
{
if(!IsPostBack)
{
TextBox tb = (TextBox)PreviousPage.FindControl("txt2");
Response.Write(tb.Text);}
}

You will need to transfer the value of the previous page's txt2.Text to a textbox or label on the new page if you are wanting to do any more postbacks on the second page, otherwise you will lose that value.

Option 2:

You could also use a Session variable surely to store your data?!

Session["text"] = txt2.Text;

Answer 2

一旦您进入了新页面，最后一页可能就不见了，建议您在会话中传输数据。

Answer 3

Are you referring to ASP.NET 2.0 Wizard Control ? An example is in the link.