0

以下代码按预期工作：

<?php
//filename is noproblem.php
//Assign each letter a ratio
$ratios = array(
'A' => 1,
'B' => 0.5
);

//Assign each letter a quantity retrieved from POST
$quantities = array(
                'A' => $_POST['AQuantity'],
                'B' => $_POST['BQuantity']
        );

//Assign each letter a value 
$values = array(
                'A' => ($ratios['A']*$quantities['A']),
                'B' => ($ratios['B']*$quantities['B'])
        );

echo "Quantity A = "; echo($quantities['A']); echo "<br>";
echo "Value A = "; echo($values['A']); echo "<br>";
echo "Quantity B = "; echo($quantities['B']); echo "<br>";
echo "Value B = "; echo($values['B']);
?>  

<html>
<form name="Quantities" action="noproblem.php" method="post">
<br>
<input type="submit" value="Insert">
<br>                                    
Quantity for A<input type="text" name="AQuantity" size="4 "value="<?php if($_POST['AQuantity']>0) {echo htmlspecialchars($_POST['AQuantity']);} else {echo 0;} ?>">
<br>
Quantity for B<input type="text" name="BQuantity" size="4" value="<?php if($_POST['BQuantity']>0) {echo htmlspecialchars($_POST['BQuantity']);} else {echo 0;} ?>">
</form> 
</html>

但是，问题是我需要 Quantities 和 Values 变量稍后转移到另一个 PHP 文件中，该文件只能包含 PHP 代码（JPGraph）。这可以通过使用 $_SESSION 变量来实现，但随后表单提交突然需要按两次。违规代码：

<?php
//filename is problem.php
session_start();

//Assign each letter a ratio
$ratios = array(
'A' => 1,
'B' => 0.5
);


$_SESSION = array(
        //Assign each letter a quantity retrieved from POST
        'quantities' => array(
                'A' => $_POST['AQuantity'],
                'B' => $_POST['BQuantity']
        ),
        //Assign each letter a USD Value from API data and their respective quantities
        'values' => array(
                'A' => ($ratios['A']*$_SESSION['quantities']['A']),
                'B' => ($ratios['B']*$_SESSION['quantities']['B'])
        ));
echo "Quantity A = "; echo($_SESSION['quantities']['A']); echo "<br>";
echo "Value A = "; echo($_SESSION['values']['A']); echo "<br>";
echo "Quantity B = "; echo($_SESSION['quantities']['B']); echo "<br>";
echo "Value B = "; echo($_SESSION['values']['B']);
?>  

<html>
<form name="Quantities" action="problem.php" method="post">
<br>
<input type="submit" value="Insert">
<br>                                    
Quantity for A<input type="text" name="AQuantity" size="4 "value="<?php if($_POST['AQuantity']>0) {echo htmlspecialchars($_POST['AQuantity']);} else {echo 0;} ?>">
<br>
Quantity for B<input type="text" name="BQuantity" size="4" value="<?php if($_POST['BQuantity']>0) {echo htmlspecialchars($_POST['BQuantity']);} else {echo 0;} ?>">
</form> 
</html>

我不能理解 SESSION 是如何工作的，所以在这方面的一些启示将不胜感激。首先，我需要知道如何修复代码，以便在使用 SESSION 时只需按一下按钮即可正确计算。我知道一个不太理想的解决方案是将每个需要的变量复制到 $_SESSION 数组中，并在该文件的主体中使用非 SESSION 变量。当然，还有比这更优雅的方式。

4

3 回答 3

0

试试这个，但是，这不是最佳实践，它只是解决了你的问题：

<?php
//filename is problem.php
session_start();

//Assign each letter a ratio
$ratios = array(
'A' => 1,
'B' => 0.5
);
$quantities = array(
                'A' => $_POST['AQuantity'],
                'B' => $_POST['BQuantity']
        );

//Assign each letter a value 
$values = array(
                'A' => ($ratios['A']*$quantities['A']),
                'B' => ($ratios['B']*$quantities['B'])
        );

$_SESSION['quantities'] = $quantities;
$_SESSION['values'] = $values;

echo "Quantity A = "; echo($_SESSION['quantities']['A']); echo "<br>";
echo "Value A = "; echo($_SESSION['values']['A']); echo "<br>";
echo "Quantity B = "; echo($_SESSION['quantities']['B']); echo "<br>";
echo "Value B = "; echo($_SESSION['values']['B']);
?>
于 2013-03-30T18:29:21.390 回答
0

这与 $_SESSION 无关，而是与函数调用（在本例中为 arra()）有关。

您尝试使用在它返回后设置的值调用对 array() 的第一次调用。所以你第一次乘以0。就这样。

于 2013-03-30T18:45:42.473 回答
0

不确定您到底要做什么，但是您可以执行以下操作：

<?php
//filename is noproblem.php
//Assign each letter a ratio
$ratios = array(
'A' => 1,
'B' => 0.5
);

if ( !empty($_POST) ) {
   //Assign each letter a quantity retrieved from POST
   $_SESSION['quantities'] = array(
                'A' => intval($_POST['AQuantity']),
                'B' => intval($_POST['BQuantity'])
        );

   //Assign each letter a value 
   $_SESSION['values'] = array(
                'A' => ($ratios['A'] * $_SESSION['quantities']['A']),
                'B' => ($ratios['B'] * $_SESSION['quantities']['B'])
        );

   echo "Quantity A = "; echo($_SESSION['quantities']['A']); echo "<br>";
   echo "Value A = "; echo($_SESSION['values']['A']); echo "<br>";
   echo "Quantity B = "; echo($_SESSION['quantities']['B']); echo "<br>";
   echo "Value B = "; echo($_SESSION['values']['B']);
}
?>  

<html>
<form name="Quantities" action="noproblem.php" method="post">
<br>
<input type="submit" value="Insert">
<br>                                    
Quantity for A<input type="text" name="AQuantity" size="4 "value="<?php if(!empty($_SESSION['quantities']['A'])) {echo htmlspecialchars($_SESSION['quantities']['A']);} else {echo 0;} ?>">
<br>
Quantity for B<input type="text" name="BQuantity" size="4" value="<?php if(!empty($_SESSION['quantities']['B'])) {echo htmlspecialchars($_SESSION['quantities']['B']);} else {echo 0;} ?>">
</form> 
</html>

This sets the SESSION values and then uses them if they are not empty. Notice that I wrapped your POST values in intval() to enforce a number also. Not sure if this will help, but here is a session tutorial. Assuming you use session_start() in your next PHP script, the variables you set here should be availabe.

于 2013-03-30T18:46:10.347 回答