C# 使用信号器从实时SQL更新数据时出现问题
我使用SignalR实时更新记录，并将它们显示在一个表中，以便客户端连接到SQL，我建立连接，当我运行应用程序时，它们加载所有数据，但当我更新数据库时，更新不会显示在客户端表中，但当我在浏览器中给出F5（刷新）时，当前数据刚刚显示出来。我找不到错误，也没有看到任何控制台错误。我附上了建议代码：）谢谢 客户：C# 使用信号器从实时SQL更新数据时出现问题,c#,asp.net-core-2.0,signalr-hub,asp.net-core-signalr,C#,Asp.net Core 2.0,Signalr Hub,Asp.net Core Signalr,我使用SignalR实时更新记录，并将它们显示在一个表中，以便客户端连接到SQL，我建立连接，当我运行应用程序时，它们加载所有数据，但当我更新数据库时，更新不会显示在客户端表中，但当我在浏览器中给出F5（刷新）时，当前数据刚刚显示出来。我找不到错误，也没有看到任何控制台错误。我附上了建议代码：）谢谢 客户： <body> <h1>Hola</h1> <div class="table table-responsive"> <tabl
<body>
<h1>Hola</h1>
<div class="table table-responsive">
<table id="tbl-productos" class="table table-bordered table-striped"></table>
</div>
<script src="~/jquery/jquery.min.js"></script>
<script src="~/aspnet/signalr/dist/browser/signalr.min.js"></script>
<script>
$(function () {
fnCrearTabla();
});
function fnCrearTabla() {
var tabla = $("#tbl-productos");
$.ajax({
url: "/Home/listadoProductos",
type: "GET",
contentType: "application/json; charset-utf-8",
dataType: "json",
success: function (data) {
if (data.length > 0) {
//tabla.empty();
var thead = "<tr>";
thead += "<th>id</th>"
thead += "<th>nombre</th>"
thead += "<th>precio</th>"
thead += "<th>Stock</th>"
thead += "</tr>"
tabla.append(thead);
var array = [];
var tbody = "";
for (var i = 0; i < data.length; i++) {
tbody += "<tr>";
tbody += "<td>" + data[i].id + "</td>"
tbody += "<td>" + data[i].nombre + "</td>"
tbody += "<td>" + data[i].precio + "</td>"
tbody += "<td>" + data[i].stock + "</td>"
tbody += "</tr>"
}
array.push(tbody);
tabla.append(array.join(""));
}
},
error: function (e) {
console.error(e);
}
});
}
var connection = new signalR.HubConnectionBuilder().withUrl("http://localhost:63257/tablaHub").build();
//connection.serverTimeoutInMilliseconds = 100000; // 100 second}
connection.on("ActualizarGrilla", function () {
fnCrearTabla();
});
connection.start().catch(function () {
console.error(e);
});
</script>
public class Startup
{
private readonly IWebHostEnvironment _webHostEnvironment;
private readonly IConfiguration _configuration;
public Startup(IWebHostEnvironment webHostEnvironment)
{
this._webHostEnvironment = webHostEnvironment;
var builder = new ConfigurationBuilder()
.SetBasePath(_webHostEnvironment.ContentRootPath)
.AddJsonFile("appsettings.json")
.AddEnvironmentVariables();
_configuration = builder.Build();
}
public void ConfigureServices(IServiceCollection services)
{
services.AddSingleton(_configuration);
#region IOC
services.AddScoped<IProductoRepositorio, ProductoRepositorio>();
services.AddScoped<IProductoServicio, ProductoServicio>();
#endregion
services.AddSignalR();
services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_3_0);
}
public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
app.UseDeveloperExceptionPage();
app.UseStaticFiles();
app.UseEndpoints(endpoints =>
{
endpoints.MapHub<TablaHub>("/tablaHub");
endpoints.MapControllerRoute("default", "{controller=Home}/{action=Index}/{id?}");
});
}
}
我认为您可能面临缓存问题，因为您正在进行ajax调用。您可以从查看浏览器中的网络流量开始，查看在您进行更改时，浏览器是否正在调用后端以获取数据。如果您在fnCrearTabla中添加一些控制台日志记录来检查您是否接收到来自signalR的消息，那么这对调试非常有用。下面的代码将禁用缓存
$.ajax({ cache: false, ...});
public class ProductoRepositorio : IProductoRepositorio
{
private readonly IConfiguration _configuration;
private readonly IHubContext<TablaHub> _tablaHub;
public ProductoRepositorio(IConfiguration configuration,
IHubContext<TablaHub> tablaHub)
{
this._configuration = configuration;
this._tablaHub = tablaHub;
}
public IEnumerable<Producto> Get()
{
List<Producto> listProducto = null;
Producto oProducto = null;
SqlDependency dependency = null;
var connectionString = _configuration.GetConnectionString("dbconnection");
using (SqlConnection cn = new SqlConnection(connectionString))
{
try
{
cn.Open();
SqlCommand cmd = new SqlCommand("upsGetProductos", cn);
cmd.CommandType = CommandType.StoredProcedure;
#region SqlDependecy
cmd.Notification = null;
dependency = new SqlDependency(cmd);
dependency.OnChange += DetectarCambios;
SqlDependency.Start(connectionString);
#endregion
SqlDataReader dr = cmd.ExecuteReader();
if (dr.HasRows)
{
listProducto = new List<Producto>();
while (dr.Read())
{
oProducto = new Producto()
{
Id = dr.IsDBNull(dr.GetOrdinal("Id")) ? -1 : dr.GetInt32(dr.GetOrdinal("Id")),
Nombre = dr.IsDBNull(dr.GetOrdinal("Nombre")) ? "nodata" : dr.GetString(dr.GetOrdinal("Nombre")),
Precio = dr.IsDBNull(dr.GetOrdinal("Precio")) ? Convert.ToDecimal(0) : dr.GetDecimal(dr.GetOrdinal("Precio")),
Stock = dr.IsDBNull(dr.GetOrdinal("Stock")) ? -1 : dr.GetInt32(dr.GetOrdinal("Stock"))
};
listProducto.Add(oProducto);
}
}
return listProducto;
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
}
}
public void DetectarCambios(object sender, SqlNotificationEventArgs e)
{
if (e.Type == SqlNotificationType.Change)
{
_tablaHub.Clients.All.SendAsync("ActualizarGrilla");
}
Get();
}
public void Dispose()
{
GC.SuppressFinalize(this);
}
}
public class TablaHub : Hub
{
}
$.ajax({ cache: false, ...});