Question

我为我们的一个本地服务器编写了一个Windows服务。这个服务就像我本地机器上的gem一样，做它应该做的事情（ACCP来交换数据库数据），但我并不过分熟悉依赖项。这是构建程序的合适方法吗？

string DBP3_US = DBP3_US;
string PING_DEPENDENCY = "SELECT [SomeColumn] FROM [SomeTable];";

protected override void OnStart(string[] args)
{
    SqlDependency.Start(DBP3_US);
    Thread Ping_US = new Thread(PingThread);
    Ping_US.Name = "ping_US";
    Ping_US.Start();
}

private void PingThread()
{
    CreateCommandWithDependency(PING_DEPENDENCY, Ping_OnChange);
}

private void CreateCommandWithDependency(string queryText, OnChangeEventHandler e, string db = DBP3_US)
{
    using (SqlConnection con = new SqlConnection(db))
    using (SqlCommand cmd = con.CreateCommand())
    {
        cmd.CommandText = queryText;
        cmd.CommandType = CommandType.Text;
        cmd.Notification = null;
        SqlDependency sqlDep = new SqlDependency(cmd);
        sqlDep.OnChange += new OnChangeEventHandler(e);
        con.Open();
        cmd.ExecuteNonQuery();
    }
}

private void Ping_OnChange(object sender, SqlNotificationEventArgs e)
{
    PingDependency();
    Thread Ping_US = new Thread(PingThread);
    Ping_US.Start();
}

private void PingDependency(string db = DBP3_US)
{
    // Do whatever operations are required.
}

Answer 1

小心使用SqlDependency类来监视数据库表中的更改 - 它具有内存泄漏的problems。但是，您可以使用自己的DDL触发器和SQL Service Broker API实现，也可以使用其中一个开源项目，例如： SqlDependencyEx：

int changesReceived = 0;
using (SqlDependencyEx sqlDependency = new SqlDependencyEx(
          TEST_CONNECTION_STRING, TEST_DATABASE_NAME, TEST_TABLE_NAME)) 
{
    sqlDependency.TableChanged += (o, e) => changesReceived++;
    sqlDependency.Start();

    // Make table changes.
    MakeTableInsertDeleteChanges(changesCount);

    // Wait a little bit to receive all changes.
    Thread.Sleep(1000);
}

Assert.AreEqual(changesCount, changesReceived);

希望这有帮助。

与Service Broker的Sql依赖关系

1 个答案: