Passing Values from One Page to Another Page – ASP.NET

Passing parameters from one page to another is a very common task in Web development. Granted, its importance and frequency has faded a bit with ASP.NET’s inherent preference for postback forms, but
regardless, there are still many situations in which you need to pass data from one Web page to another.

There are three widely used methods of passing values from one page to another in ASP.NET
Main

1. Using Query String

We usually pass value through query string of the page and then this value is pulled from Request object in another page.

FirstForm.aspx.cs
—————–
Response.Redirect(“SecondForm.aspx?Parameter=” + TextBox1.Text);

SecondForm.aspx.cs
——————
TextBox1.Text = Request. QueryString["Parameter"].ToString();

This is the most reliable way when you are passing integer kind of value or other short parameters.More advance in this method if you are using any special characters in the value while passing it through query string, you must encode the value before passing it to next page. So our code snippet of will be something like this:

FirstForm.aspx.cs
—————
Response.Redirect(“SecondForm.aspx?Parameter=” + Server.UrlEncode(TextBox1.Text));

SecondForm.aspx.cs
—————–
TextBox1.Text = Server.UrlDecode(Request.QueryString["Parameter"].ToString());

2. Passing value through context object

Passing value through context object is another widely used method.

FirstForm.aspx.cs
—————
TextBox1.Text = this.Context.Items["Parameter"].ToString();

SecondForm.aspx.cs
——————
this.Context.Items["Parameter"] = TextBox1.Text;
Server.Transfer(“SecondForm.aspx”, true);

Note that we are navigating to another page using Server.Transfer instead of Response.Redirect.Some of us also use Session object to pass values. In that method, value is store in Session object and then later pulled out from Session object in Second page.

3. Posting form to another page instead of PostBack

Third method of passing value by posting page to another form. Here is the example of that:

FirstForm.aspx.cs
—————
private void Page_Load(object sender, System.EventArgs e)
{
buttonSubmit.Attributes.Add(“onclick”, “return PostPage();”);
}

And we create a javascript function to post the form.

SecondForm.aspx.cs
—————–

function PostPage()
{
document.Form1.action = “SecondForm.aspx”;
document.Form1.method = “POST”;
document.Form1.submit();
}
TextBox1.Text = Request.Form["TextBox1"].ToString();

Here we are posting the form to another page instead of itself. You might get viewstate invalid or error in second page using this method. To handle this error is to put EnableViewStateMac=false

4. Another method is by adding PostBackURL property of control for cross page post back

In ASP.NET 2.0, Microsoft has solved this problem by adding PostBackURL property of control for cross page post back. Implementation is a matter of setting one property of control and you are done.

FirstForm.aspx.cs
————–
<asp:Button id=buttonPassValue style=”Z-INDEX: 102″ runat=”server” Text=”Button”         PostBackUrl=”~/SecondForm.aspx”></asp:Button>

SecondForm.aspx.cs
—————–
TextBox1.Text = Request.Form["TextBox1"].ToString();

In above example, we are assigning PostBackUrl property of the button we can determine the page to which it will post instead of itself. In next page, we can access all controls of the previous page using Request object.

You can also use PreviousPage class to access controls of previous page instead of using classic Request object.

SecondForm.aspx
—————
TextBox textBoxTemp = (TextBox) PreviousPage.FindControl(“TextBox1″);
TextBox1.Text = textBoxTemp.Text;

As you have noticed, this is also a simple and clean implementation of passing value between pages.
Conclusion Passing values between pages is another common task accomplishes in web based development. As we have discussed many of mechanisms above, I prefer and recommend to use Query String then other
methods for its clean and simple implementation as long as your parameter doesnt have security concern.