Converting string concatenations

FOD · September 6th, 2011, 11:14 PM

I have a web form with 20 textboxes on it which I've named txtItem1 through txtItem20. Ultimately my goal is to collect the data from these 20 textboxes and place them in an array (and eventually my database) using a loop through the textbox numbers (rather than individually call them out and add them). When I attempt to concatenate the variable name "txtItem" + i++ + ".text" in a do while loop all it adds to the array is the string of the concatenation. How do I to convert/cast the concatenation so that it provides the same result as txtItem1.text without treating it as just text?

I'm guessing the answer is simple and I'm just overlooking it.

Thanks in advance!

Shasur · September 7th, 2011, 07:46 AM

Hi

Here are few hints

http://dotnetdud.blogspot.com/2011/0...arraylist.html

http://www.dreamincode.net/forums/to...-of-textboxes/

Cheers
Shasur

FOD · September 7th, 2011, 10:14 PM

Thanks Shasur I'll check them out and let you know if I have any questions!

Pushpa.B · September 8th, 2011, 08:26 AM

Quote:

Originally Posted by FOD

I have a web form with 20 textboxes on it which I've named txtItem1 through txtItem20. Ultimately my goal is to collect the data from these 20 textboxes and place them in an array (and eventually my database) using a loop through the textbox numbers (rather than individually call them out and add them). When I attempt to concatenate the variable name "txtItem" + i++ + ".text" in a do while loop all it adds to the array is the string of the concatenation. How do I to convert/cast the concatenation so that it provides the same result as txtItem1.text without treating it as just text?

I'm guessing the answer is simple and I'm just overlooking it.

Thanks in advance!

Hi,

i think if u create a instance for textbox in a loop and add i++ to that instance than it may work.

i am not sure about this but i am giving just suggetion.

regards,
Pushpa B

FOD · September 13th, 2011, 12:09 AM

So I thought I had figured it out but now I am getting a Null Reference Exception even though the textboxes have data in them. Just to clarify what I am trying to do is pull the text out of a bunch of textboxes so I can push it over to my database using EF. Any thoughts on what may be causing the error and how I should fix it?

for (int i = 1; i <= 20; i++)
{
var quicklistitems = new QuickListItem();
quicklistitems.ListID = quicklist.ID;
quicklistitems.Item = ((TextBox)FindControl("txtListItem" + i)).Text;
context.QuickListItems.AddObject(quicklistitems);
}

Thanks,
FOD

mmorgan30 · May 1st, 2014, 01:58 AM

This method concatenating your text boxes together should work. However, there is 1 minor flaw with "FindControl", it only finds controls that are a direct child of the page/control being searched. If you know that the control exists within the page/control and its not being found when you do your search it is more than likely a grandchild of the page/control that you are calling "FindControl" on. In this instance you need a recursive search to traverse all children and grandchildren controls until it is found or null if not found.

Code:

public Control FindControlRecursive( Control root, String controlId )
{
     Control rVal = null;
      
     if( root.ID == controlId )
           rVal = root;
     else
     {
          // perform recursive depth first search until control found
          foreach( Control c in root.Controls )
          {
               rVal = FindControlRecursive( c, controlId )
               if( rVal != null )
                     break; // found control stop looking 
          }
     }
    return rVal; // we return the control or null if not found
}

public Control FindControlRecursive( Page root, String controlId )
{
      Control rVal = null;
      
      // perform recursive depth first search until control found
      foreach( Control c in root.Controls )
       {
            rVal = FindControlRecursive( c, controlId )
            if( rVal != null )
                 break; // found control stop looking 
       }
}