How do I server.transfer the changed value of a control

[j9]

I have a textbox, txtName, runat=server. When the submit button is clicked, I want to change the value of txtName in the code-behind page and then submit the changed form variable to another page. It seems that the value of txtName must also be changed client-side in order for the value to persist to the next page. Here's a brief of what I have. The changed value of txtName does not carry over to Page2.aspx:

private void btnSubmit_Click(object sender, System.EventArgs e)
{
txtName.Value = "somethingelse";
Server.Transfer("Page2.aspx");
}

 

[tgreer]

So the user enters "A" in a textbox, submits the form.

Server-side code changes the value of the server control to "B".

Then you do a server.transfer, passing the values, and the second page sees the value of the textbox as "A".

That's because you're not transferring server controls/properties, you're transferring the HTTP form data.

Can you change your sequence of events?

I think you'll have to change the HTTP Form data to correctly transfer:

Request.Form.Set()



Thomas D. Greer

http://www.tgreer.com

Providing PostScript & PDF
Training, Development & Consulting

 

[ca8msm]

You simply have to set another parameter (preserverForm) to True to perserve the form and querystring items. e.g.

Server.Transfer("AnotherPage.aspx",True)

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[j9]

Thank you, but how do I do that? What is Request.Form.Set()? I couldn't find any documentation.

 

[j9]

Unless I'm missing something, Server.Transfer("AnotherPage.aspx",True) does not pick up the values that were changed server-side. I think tgreer is right in that I need to change the http form data. I'm just not sure how to go about it. Thank you.

 

[tgreer]

Request.Form.Set() is the method you would use to set form data server-side.

http://msdn.microsoft.com/library/d...html/ef3a75f3-aaff-4f0e-b52f-3206c0886476.asp

Thomas D. Greer

http://www.tgreer.com

Providing PostScript & PDF
Training, Development & Consulting

 

[tgreer]

Sorry, looks like the Form collection is read-only.

So you just have to do it another way. For example, you can use HttpContext, or you can build a querystring from your form data, and do a redirect instead of a transfer.

This is an unusual situation, would you mind explaining why you need to do this?



Thomas D. Greer

http://www.tgreer.com

Providing PostScript & PDF
Training, Development & Consulting

 

[j9]

Yep, I ran into the read-only exception, too. I was trying to give a simple code example. What really happens is this:

1. The user fills in a bunch of text fields to create a new record.
2. The user clicks the 'save & continue' button that calls btnSubmit_Click().
3. btnSubmit_Click inserts the new record into the database, gets the id of the new record, and SHOULD then submit the value of the id in a hidden form field to the next page.

I suppose I could use a session variable, but this is really bugging me now

 

[tgreer]

Can't the second page use the transferred data to get the record's ID?

Thomas D. Greer

http://www.tgreer.com

Providing PostScript & PDF
Training, Development & Consulting

 

[tgreer]

QueryString will work. In the first page:

Server.Transfer("WebForm2.aspx?myId=3",true);


In the second page:

string x = Request.QueryString["myId"].ToString();


Thomas D. Greer

http://www.tgreer.com

Providing PostScript & PDF
Training, Development & Consulting

 

[j9]

Thank you very much for your help, but I was trying to avoid sending the id in the URL. I guess I can just use a session.

 

[tgreer]

Or hit the database again. If you have enough information in the form to write the database record, you have enough information to READ that record.

So you have to choose between the following evils:

1) Session variable
2) Querystring
3) second database hit



Thomas D. Greer

http://www.tgreer.com

Providing PostScript & PDF
Training, Development & Consulting

 

[j9]

Good point on the db hit. I think I'll go with a session. Thanks for sticking with me!