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Setting SELECTED value of a drop down list that is populated via a database lookup when posting a form back to itself

Posted on 2014-02-04
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Last Modified: 2014-02-04
Hello,

I am fairly new to PHP having come from a .NET background and one thing I am missing is the POSTBACK function of the forms and what that offered.

In essence what I am trying to do is have a user select two values from two drop down lists then use these two values and query the database to return the correct value.

If possible I would prefer to just have the one page and then retain the values that are selected on the page in the DDLs when the final value is displayed.

I know it is possible just to have the form action redirect to another page where I could show the values that have been selected but I would much prefer to keep the user not he one page and just keep the selected values int he DDL like I would have done in .NET.

After a search I have found options on setting the selected value but unless I am missing something with the syntax then these don't seem to be working wight eh way I am populating the menu.

I have attached the code I am using for the population of the DDLs below.

$conn = dbconn();

		$query = "SELECT width, mm, inch FROM tbl_width ORDER by mm ASC" or die("Error in the consult.." . mysqli_error($conn));

		$result = $conn->query($query);

		$return_height = "";

		while ($row = mysqli_fetch_array($result)){
			$return_height .= "<option value=\"" . $row['width'] . "\">" . $row['mm'] . " mm ( " . $row['inch'] . " inches )</option>";
		}

		return $return_height;

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Many thanks.
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Question by:Lee Redhead
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Accepted Solution

by:
Lee Redhead earned 0 total points
ID: 39833191
I have managed to find a solution to this by the following.

if (isset($sel_width)) {
          $selected = ($row['width'] == $sel_width ? 'selected' : '');
          }
		
			$return_height .= "<option value=\"" . $row['width'] . "\"" . $selected . ">" . $row['mm'] . " mm ( " . $row['inch'] . " inches )</option>";

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This works by running the check outside of the complete line which I think was what I was doing wrong before.
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Author Closing Comment

by:Lee Redhead
ID: 39833196
Applying some thought to what was going wrong setting the value as a variable outside of the return worked.
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