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我想創建一個網格並自動更新它，當數據在數據庫中發生變化時。它適用於簡單的表格控件。Signalr和Devexpress
public partial class index : System.Web.UI.Page
{
static string connectionString = @"Data Source=*******;initial catalog=Test;persist security info=True; Integrated Security=SSPI;";
protected void Page_Load(object sender, EventArgs e)
{
}
[WebMethod]
public static IEnumerable<Person> GetData()
{
using (var connection = new SqlConnection(connectionString))
{
connection.Open();
using (SqlCommand command = new SqlCommand(@"SELECT [Id],[Name] FROM [dbo].[Persons]", connection))
{
command.Notification = null;
SqlDependency.Start(connectionString);
SqlDependency dependency = new SqlDependency(command);
dependency.OnChange += new OnChangeEventHandler(Dependency_OnChange);
if (connection.State == ConnectionState.Closed)
connection.Open();
using (var reader = command.ExecuteReader())
return reader.Cast<IDataRecord>()
.Select(x => new Person(x.GetInt32(0), x.GetString(1))).ToList();
}
}
}
private static void Dependency_OnChange(object sender, SqlNotificationEventArgs e)
{
MyHub.Show();
}
public void FillGrid()
{
List<Person> persons = new List<Person>();
using (var connection = new SqlConnection(connectionString))
{
connection.Open();
using (SqlCommand command = new SqlCommand(@"SELECT [Id],[Name] FROM [dbo].[Persons]", connection))
{
if (connection.State == ConnectionState.Closed)
connection.Open();
using (SqlDataReader rdr = command.ExecuteReader())
{
while (rdr.Read())
{
var id = rdr.GetInt32(0);
var name = rdr.GetString(1);
persons.Add(new Person(id, name));
}
}
}
}
grid.DataSource = persons;
grid.DataBind();
}
}
public class MyHub : Hub
{
public static void Show()
{
IHubContext context = GlobalHost.ConnectionManager.GetHubContext<MyHub>();
context.Clients.All.displayStatus();
}
}
而且apsx頁：
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
<script src="Scripts/jquery-1.6.4.min.js"></script>
<script src="Scripts/jquery.signalR-2.2.2.min.js"></script>
<script src="signalr/hubs"></script>
<script type="text/javascript">
$(function() {
// Proxy created on the fly
var job = $.connection.myHub;
// Declare a function on the job hub so the server can invoke it
job.client.displayStatus = function() {
getData();
};
// Start the connection
$.connection.hub.start();
getData();
});
function getData()
{
var $tbl = $('#tbl');
$.ajax({
url: '/index.aspx/GetData',
contentType: 'application/json;charset=utf-8',
datatype: 'json',
type: 'POST',
success: function (data) {
if (data.d.length > 0) {
var newdata = data.d;
$tbl.empty();
$tbl.append(' <tr><th>ID</th><th>Name</th></tr>');
var rows = [];
for (var i = 0; i < newdata.length; i++) {
rows.push(' <tr><td>' + newdata[i].Id + '</td><td>' + newdata[i].Name + '</td><td></tr>');
}
$tbl.append(rows.join(''));
}
}
});
}
</script>
</head>
<body>
<form id="form1" runat="server">
<div>
<table id="tbl"></table>
<dx:ASPxGridView ID="grid" runat="server"></dx:ASPxGridView>
</div>
</form>
</body>
</html>
不過，我想用一個Devepress Aspxgridview。 Devexpress網站聲明他們不支持SignalR。但是，由於在數據庫中數據發生變化時會觸發Javascript函數，是否有可能以某種方式強制客戶端從服務器獲取數據？強制回發和/或調用FillGrid方法？ （從js創建網格是不可能的，因爲AspxgridView控件要複雜得多）。
來源：https://www.youtube.com/watch?v=30m-7wpmbrc
Thx確實有效...... – Charles