试图获取非对象PHP的属性

Question

The code worked properly till yesterday... Then wamp crashed... I reinstalled wamp and its throwing the error

Trying to get property of non-object

$con=mysqli_connect('localhost' ,'root' ,'' ,'images');

$result="SELECT * from images";
$stmt=$con->query($result);
if ($stmt->num_rows>0)
{
    while ($row=mysqli_fetch_array($stmt))
    {
        echo '<img height="300" width="300" src="data:image;base64,'.$row[2].' "> ';
    } 

Answer 1

First check weather your $stmt have something inside before accessing its childs.

var_dump($stmt);

Answer 2

The two objects in the you code you are trying to use a property is $stmt->num_rows .

It seems something wrong in the db.
Could you check the connection and the db?
Maybe when you reinstall you clean the db.

Answer 3

According to your code the error seem correct because you get output in form of object just use

$con=mysqli_connect('localhost' ,'root' ,'' ,'images');

$result="SELECT * from images";
$stmt=$con->query($result);
if ($stmt->num_rows>0)
{
    while ($row=mysqli_fetch_array->($stmt))
    {
        echo '<img height="300" width="300" src="data:image;base64,'.$row[2].' "> ';
    } 

Answer 4

I would expect that when you reinstalled you did not re-create/restore the images database. But adding the error checking that should have been there in the first place should identify the problem.

Also you should stick to Proceedural or Object oriented mysqli and not mix the 2 as you have done.

$con = new mysqli_connect('localhost' ,'root' ,'' ,'images');
if ($con->connect_error) {
    die('Connect Error (' . $mysqli->connect_errno . ') '
            . $mysqli->connect_error);
}

$sql = "SELECT * from images";

// $con->query returns a result object
$result = $con->query($result);
if ( ! $result ) {
   die("Error: %s.\n", $stmt->error);
}

if ($result->num_rows > 0)
{
    while ($row = $result->fetch_assoc())
    {
        echo '<img height="300" width="300" src="data:image;base64,'.$row[2].' "> ';
    } 

This will now at least show you any errors that happen during the processing of the database.