这里我试图从数据库中获取数据，并使用PHP将其显示在下拉列表中。虽然表中有可用的数据，但它不会将其显示在下拉列表中。这背后的问题是什么，解决方案是什么？？？
<!DOCTYPE html>
<html>
<?php
include 'header.php';
include 'footer.php';
include './config.php';
?>
<head>
<meta charset="UTF-8">
<title></title>
</head>
<body>
<div id="page-wrapper">
<div class="row">
<div class="col-lg-12">
<h1 class="page-header">Add Product</h1>
</div>
<!-- /.col-lg-12 -->
</div>
<div class="row">
<div class="col-lg-12">
<div class="panel panel-default">
<div class="panel-heading">
Product
</div>
<div class="panel-body">
<div class="dataTable_wrapper">
<form action="AddProduct.php" method="POST" role="form">
<div class="col-lg-6">
<div class="form-group">
<label>Project Name</label>
<?php
$sqll="SELECT * FROM project_master";
echo "<select class='form-control' name='project'>";
echo "<option value=''>Select One</option>";
foreach ($conn->query($sqll) as $row){
echo "<option value=$row[Project_id]>$row[Project_title]</option>";
}
echo "</select>";
?>
</div>
<div class="form-group">
<label>Product Name</label>
<input class="form-control" name="Product_name" type="text" id="Product_name" required="required" title="Enter Product Name">
</div>
<button type="submit" class="btn btn-primary" id="submit" data-toggle="modal" data-target="#myModal">Submit Query</button>
<button type="reset" class="btn btn-primary">Reset</button>
</div>
<div class="modal fade" id="myModal" tabindex="-1" role="dialog" aria-labelledby="myModalLabel" aria-hidden="true">
<div class="modal-dialog">
<div class="modal-content">
<div class="modal-header">
<button type="button" class="close" data-dismiss="modal" aria-hidden="true">×</button>
<h4 class="modal-title" id="myModalLabel">Particular Circle Will be included for selected Project</h4>
</div>
<div class="modal-body">
Do you want to proceed??
</div>
<div class="modal-footer">
<button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
<button type="submit" class="btn btn-primary" id="submit">Save changes</button>
</div>
</div>
<!-- /.modal-content -->
</div>
<!-- /.modal-dialog -->
</div>
</form>
</div>
</div>
</div>
</div>
</div>
</div>
</body>
页面来源：
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1">
<meta name="description" content="">
<meta name="author" content="">
<title>Test Management Tool</title>
<!-- Bootstrap Core CSS -->
<link href="../../bower_components/bootstrap/dist/css/bootstrap.min.css" rel="stylesheet">
<!-- MetisMenu CSS -->
<link href="../../bower_components/metisMenu/dist/metisMenu.min.css" rel="stylesheet">
<!-- Custom CSS -->
<link href="../../dist/css/sb-admin-2.css" rel="stylesheet">
<!-- Custom Fonts -->
<link href="../../bower_components/font-awesome/css/font-awesome.min.css" rel="stylesheet" type="text/css">
<!-- HTML5 Shim and Respond.js IE8 support of HTML5 elements and media queries -->
<!-- WARNING: Respond.js doesn't work if you view the page via file:// -->
<!--[if lt IE 9]>
<script src="https://oss.maxcdn.com/libs/html5shiv/3.7.0/html5shiv.js"></script>
<script src="https://oss.maxcdn.com/libs/respond.js/1.4.2/respond.min.js"></script>
<![endif]-->
</head>
<body>
<div id="wrapper">
<!-- Navigation -->
<nav class="navbar navbar-default navbar-static-top" role="navigation" style="margin-bottom: 0">
<div class="navbar-header">
<button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".navbar-collapse">
<span class="sr-only">Toggle navigation</span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
<a class="navbar-brand" href="DeshbordAdmin.php"><i class="fa fa-home"></i>Administrator</a>
</div>
<!-- /.navbar-header -->
<ul class="nav navbar-top-links navbar-right">
<li class="dropdown">
</li>
<!-- /.dropdown -->
<li class="dropdown">
</li>
<!-- /.dropdown -->
<li class="dropdown">
<!-- /.dropdown-alerts -->
</li>
<!-- /.dropdown -->
<li class="dropdown">
<a class="dropdown-toggle" data-toggle="dropdown" href="#">
<i class="fa fa-user fa-fw"></i> <i class="fa fa-caret-down"></i>
</a>
<ul class="dropdown-menu dropdown-user">
<li><a href="#"><i class="fa fa-user fa-fw"></i> User Profile</a>
</li>
<li><a href="#"><i class="fa fa-gear fa-fw"></i> Settings</a>
</li>
<li class="divider"></li>
<li><a href="../../logout.php"><i class="fa fa-sign-out fa-fw"></i> Logout</a>
</li>
</ul>
<!-- /.dropdown-user -->
</li>
<!-- /.dropdown -->
</ul>
</nav>
</div>
<script src="../../bower_components/jquery/dist/jquery.min.js"></script>
<!-- Bootstrap Core JavaScript -->
<script src="../../bower_components/bootstrap/dist/js/bootstrap.min.js"> </script>
<!-- Metis Menu Plugin JavaScript -->
<script src="../../bower_components/metisMenu/dist/metisMenu.min.js"></script>
<!-- Custom Theme JavaScript -->
<script src="../../dist/js/sb-admin-2.js"></script>
<!-- Page-Level Demo Scripts - Notifications - Use for reference -->
<script>
// tooltip demo
$('.tooltip-demo').tooltip({
selector: "[data-toggle=tooltip]",
container: "body"
})
// popover demo
$("[data-toggle=popover]")
.popover()
</script>
</body>
</html><!DOCTYPE html>
<!--
To change this license header, choose License Headers in Project Properties.
To change this template file, choose Tools | Templates
and open the template in the editor.
-->
<html>
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1">
<meta name="description" content="">
<meta name="author" content="">
<title>Test Management Tool</title>
<!-- Bootstrap Core CSS -->
<link href="../../bower_components/bootstrap/dist/css/bootstrap.min.css" rel="stylesheet">
<!-- MetisMenu CSS -->
<link href="../../bower_components/metisMenu/dist/metisMenu.min.css" rel="stylesheet">
<!-- Custom CSS -->
<link href="../../dist/css/sb-admin-2.css" rel="stylesheet">
<!-- Custom Fonts -->
<link href="../../bower_components/font-awesome/css/font-awesome.min.css" rel="stylesheet" type="text/css">
<!-- HTML5 Shim and Respond.js IE8 support of HTML5 elements and media queries -->
<!-- WARNING: Respond.js doesn't work if you view the page via file:// -->
<!--[if lt IE 9]>
<script src="https://oss.maxcdn.com/libs/html5shiv/3.7.0/html5shiv.js"></script>
<script src="https://oss.maxcdn.com/libs/respond.js/1.4.2/respond.min.js"></script>
<![endif]-->
</head>
<body>
<div id="wrapper">
<!-- Navigation -->
<div class="navbar-default sidebar" role="navigation">
<div class="sidebar-nav navbar-collapse">
<ul class="nav" id="side-menu">
<li class="sidebar-search">
<div class="input-group custom-search-form">
<input type="text" class="form-control" placeholder="Search...">
<span class="input-group-btn">
<button class="btn btn-default" type="button">
<i class="fa fa-search"></i>
</button>
</span>
</div>
<!-- /input-group -->
</li>
<li>
<a href="DeshbordAdmin.php"><i class="fa fa-dashboard fa-fw"></i> Dashboard</a>
</li>
<li>
<a href="#"><i class="fa fa-users"></i> User<span class="fa arrow"></span></a>
<ul class="nav nav-second-level">
<li>
<a href="AddUser.php">Add User</a>
</li>
<li>
<a href="morris.html">Delete User</a>
</li>
</ul>
<!-- /.nav-second-level -->
</li>
<li>
<a href="#"><i class="fa fa-cubes"></i> Project<span class="fa arrow"></span></a>
<ul class="nav nav-second-level">
<li>
<a href="AddProject.php">Add Project</a>
</li>
<li>
<a href="morris.html">View Project</a>
</li>
</ul>
<!-- /.nav-second-level -->
</li>
<li>
<a href="#"><i class="fa fa-book"></i> Product<span class="fa arrow"></span></a>
<ul class="nav nav-second-level">
<li>
<a href="AddProduct.php">Add Product</a>
</li>
<li>
<a href="morris.html">Assign Product</a>
</li>
<li>
<a href="morris.html">View Product</a>
</li>
</ul>
<!-- /.nav-second-level -->
</li>
<li>
<a href="#"><i class="fa fa-sitemap fa-fw"></i>Test Suites<span class="fa arrow"></span></a>
<ul class="nav nav-second-level">
<li>
<a href="#">Add Test Suite</a>
</li>
<li>
<a href="#">Delete Test Suite</a>
</li>
<li>
<a href="#">Update Test Suite <span class="fa arrow"></span></a>
<ul class="nav nav-third-level">
<li>
<a href="#">Add Test case</a>
</li>
<li>
<a href="#">Delete Test case</a>
</li>
</ul>
<!-- /.nav-third-level -->
</li>
</ul>
<!-- /.nav-second-level -->
</li>
<li>
<a href="#"><i class="fa fa-wrench fa-fw"></i> Test Case<span class="fa arrow"></span></a>
<ul class="nav nav-second-level">
<li>
<a href="panels-wells.html">Add Test Case</a>
</li>
<li>
<a href="buttons.html">Update Test Case</a>
</li>
<li>
<a href="notifications.html">View Test Case</a>
</li>
</ul>
<!-- /.nav-second-level -->
</li>
<li>
<a href="tables.html"><i class="fa fa-circle-o-notch"></i> Circe</a>
</li>
<li>
<a href="forms.html"><i class="fa fa-edit fa-fw"></i> Forms</a>
</li>
<li>
<a href="#"><i class="fa fa-files-o fa-fw"></i> Reports<span class="fa arrow"></span></a>
<ul class="nav nav-second-level">
<li>
<a href="blank.html">Blank Page</a>
</li>
<li>
<a href="login.html">Login Page</a>
</li>
</ul>
<!-- /.nav-second-level -->
</li>
</ul>
</div>
<!-- /.sidebar-collapse -->
</div>
<!-- /.navbar-static-side -->
</nav>
</div>
<!-- /#wrapper -->
</body>
</html>
<head>
<meta charset="UTF-8">
<title></title>
</head>
<body>
<div id="page-wrapper">
<div class="row">
<div class="col-lg-12">
<h1 class="page-header">Add Product</h1>
</div>
<!-- /.col-lg-12 -->
</div>
<div class="row">
<div class="col-lg-12">
<div class="panel panel-default">
<div class="panel-heading">
Product
</div>
<div class="panel-body">
<div class="dataTable_wrapper">
<form action="AddProduct.php" method="POST" role="form">
<div class="col-lg-6">
<div class="form-group">
<label>Project Name</label>
<select class='form-control' name='project'><option value=''>Select One</option><option value=''></option> <option value=''></option><option value=''></option><option value=''></option><option value=''></option></select> </div>
<div class="form-group">
<label>Product Name</label>
<input class="form-control" name="Product_name" type="text" id="Product_name" required="required" title="Enter Product Name">
</div>
<button type="submit" class="btn btn-primary" id="submit" data-toggle="modal" data-target="#myModal">Submit Query</button>
<button type="reset" class="btn btn-primary">Reset</button>
</div>
<div class="modal fade" id="myModal" tabindex="-1" role="dialog" aria-labelledby="myModalLabel" aria-hidden="true">
<div class="modal-dialog">
<div class="modal-content">
<div class="modal-header">
<button type="button" class="close" data-dismiss="modal" aria-hidden="true">×</button>
<h4 class="modal-title" id="myModalLabel">Particular Circle Will be included for selected Project</h4>
</div>
<div class="modal-body">
Do you want to proceed??
</div>
<div class="modal-footer">
<button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
<button type="submit" class="btn btn-primary" id="submit">Save changes</button>
</div>
</div>
<!-- /.modal-content -->
</div>
<!-- /.modal-dialog -->
</div>
</form>
</div>
</div>
</div>
</div>
</div>
</div>
</body>
试试这个代码
<html>
<?php
include 'header.php';
include 'footer.php';
include './config.php';
?>
<head>
<meta charset="UTF-8">
<title></title>
</head>
<body>
<div id="page-wrapper">
<div class="row">
<div class="col-lg-12">
<h1 class="page-header">Add Product</h1>
</div>
<!-- /.col-lg-12 -->
</div>
<div class="row">
<div class="col-lg-12">
<div class="panel panel-default">
<div class="panel-heading">
Product
</div>
<div class="panel-body">
<div class="dataTable_wrapper">
<form action="AddProduct.php" method="POST" role="form">
<div class="col-lg-6">
<div class="form-group">
<label>Project Name</label>
<?php
$sqll="SELECT * FROM project_master";
echo "<select class='form-control' name='project'>";
echo "<option value=''>Select One</option>";
foreach ($conn->query($sqll) as $row){
echo "<option value=".$row['Project_id'].">".$row['Project_title']."</option>";
}
echo "</select>";
?>
</div>
<div class="form-group">
<label>Product Name</label>
<input class="form-control" name="Product_name" type="text" id="Product_name" required="required" title="Enter Product Name">
</div>
<button type="submit" class="btn btn-primary" id="submit" data-toggle="modal" data-target="#myModal">Submit Query</button>
<button type="reset" class="btn btn-primary">Reset</button>
</div>
<div class="modal fade" id="myModal" tabindex="-1" role="dialog" aria-labelledby="myModalLabel" aria-hidden="true">
<div class="modal-dialog">
<div class="modal-content">
<div class="modal-header">
<button type="button" class="close" data-dismiss="modal" aria-hidden="true">×</button>
<h4 class="modal-title" id="myModalLabel">Particular Circle Will be included for selected Project</h4>
</div>
<div class="modal-body">
Do you want to proceed??
</div>
<div class="modal-footer">
<button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
<button type="submit" class="btn btn-primary" id="submit">Save changes</button>
</div>
</div>
<!-- /.modal-content -->
</div>
<!-- /.modal-dialog -->
</div>
</form>
</div>
</div>
</div>
</div>
</div>
</div>
</body>
我认为其中一个问题是您的echo $row[project_id]中缺少单个qoute，应该是$row['project_id']。如果您将代码更改为以下内容，会发生什么情况？
<?php
$sqll="SELECT * FROM project_master";
echo "<select class='form-control' name='project'>";
echo "<option value=''>Select One</option>";
$results = $conn->query($sqll);
foreach ($results as $row) {
echo "<option value=$row[Project_id]>$row[Project_title]</option>";
}
echo "</select>";
?>
根据@Karthikeyani的建议，我有
更换此代码
$sqll="SELECT * FROM project_master"; $rows = $conn->query($sqll);
echo "<select class='form-control' name='project'>";
echo "<option value=''>Select One</option>";
while($rows->fetch_assoc() as $row){
echo "<option value=".$row['Project_id'].">".$row['Project_title']."</option>";
}
echo "</select>"; ?>