小编Dan*_*npe的帖子

我有这个代码:

    private TreeNodeCollection treeCollection;

    public Client(TcpClient c)
    {
        this.tcpClient = c;
        this.tree = null;
        this.treeCollection = new TreeNodeCollection();
        this.treeCollection.Clear();
    }

    public void AddNode(string node)
    {
        this.treeCollection.Add(node);
    }

该this.treeCollection = new TreeNodeCollection();回报

The type 'System.Windows.Forms.TreeNodeCollection' has no constructors defined

如果我删除这一行,我得到的treeCollection从未被分配,并且将始终为null ...

Field 'Client.treeCollection' is never assigned to, and will always have its default value null

如何将treeCollection指定为新的TreeNodeCollection,以便我可以使用AddNode方法向其添加节点？

当我的UITableView为空时,我正在尝试放置一个自定义的空单元格.

我使用以下代码:

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{

    int count = [self.fetchedResultsController fetchedObjects].count;
    if (count == 0) {
        return 1;
    }
    return count;
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    UITableViewCell * cell = nil;
    int count = [self.fetchedResultsController fetchedObjects].count;
    if (count == 0) {
        // return empty cell
        cell = [self getEmptyCellOfTableView:tableView cellForRowAtIndexPath:indexPath];
    } else {
        cell = [self getMyQuestionCellOfTableView:tableView cellForRowAtIndexPath:indexPath];
    }
    return cell;
}

FRC didChangeObject实现:

- (void)controller:(NSFetchedResultsController *)controller
   didChangeObject:(id)anObject
       atIndexPath:(NSIndexPath *)indexPath
     forChangeType:(NSFetchedResultsChangeType)type
      newIndexPath:(NSIndexPath *)newIndexPath
{       
    if …

我正在使用ASHX处理程序,我希望处理程序检查Session!= null.

if (context.Session["Username"] != null)

我得到这个错误指向这一行:

System.NullReferenceException:未将对象引用设置为对象的实例.

有什么问题？

这是我的代码行:

StringBuilder myCompleteMessage = new StringBuilder();
myCompleteMessage.Capacity = Int32.MaxValue-1;

尝试过:

myCompleteMessage.Capacity = myCompleteMessage.MaxCapacity-1;

我在第2行得到例外.

Exception of type 'System.OutOfMemoryException' was thrown.

堆栈跟踪:

at System.String.GetStringForStringBuilder(String value, Int32 startIndex, Int32 length, Int32 capacity)
at System.Text.StringBuilder.set_Capacity(Int32 value)
at Orca.Server.HandleClientComm(Object newClient) in C:\Users\Dan\Documents\Visual Studio 2010\Projects\msig\Orca\Server.cs:line 100
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart(Object obj)

我有这个清单:

['192', '168', '0', '1', '80', '192', '168', '0', '2', '8080']...

我想得到这个清单:

['192.168.0.1:80', '192.168.0.2:8080']...

这样做的最佳方式是什么？

使用range与list流行？

用list切片？

我使用以下内容:

"dependencies": {
    "express": "^4.0.0",
    "socket.io": "0.9.16",
    "mongoose": "^3.8.8",
    "passport": "^0.2.0",
    "passport-local": "^1.0.0",
    "express-session": "^1.0.3",
    "cookie-parser": "^1.0.1",
    "body-parser": "^1.0.2",
    "session-mongoose": "git://github.com/danpe/session-mongoose.git#master",
    "passport.socketio": "^3.0.1"
  }

设置我的socket.io授权:

io.set("authorization", passportSocketIo.authorize({
    passport : passport,
    cookieParser: cookieParser(),
    key:    settings.sessionKey,  //the cookie where express (or connect) stores its session id.
    secret: settings.sessionSecret,       //the session secret to parse the cookie
    store:  sessionStore,  //the session store that express uses
    fail: function(data, accept) {
        console.log("failed");
        // console.log(data);// *optional* callbacks on success or fail
        accept(null, false);             // second param takes …

我有这个问题:

SELECT Auctions.ID 
FROM Auctions
INNER JOIN Products ON Auctions.ProductID = Products.ID

据我所知,如果我有拍卖:

ID | ProductID
1  |   12

并且ProductID 12不在Products表中,因此不会选择该行.

如果我是对的,我想删除Products表上没有找到产品ID的所有行.(无法找到JOIN的产品)

我怎样才能做到这一点？

可能重复:
从线程返回值？

我有这个代码:

//Asynchronously start the Thread to process the Execute command request.
Thread objThread = new Thread(new ParameterizedThreadStart(ExecuteCommandSync));
//Make the thread as background thread.
objThread.IsBackground = true;
//Set the Priority of the thread.
objThread.Priority = ThreadPriority.AboveNormal;
//Start the thread.
objThread.Start(command);

问题是ExecuteCommandSync返回一个字符串.

如何捕获返回的字符串并将其返回？

我有以下代码：

    public static void Next()
    {
        Process[] processes = Process.GetProcessesByName("test");

        foreach (Process proc in processes)
            PostMessage(proc.MainWindowHandle, WM_KEYDOWN, VK_RIGHT, 0);
    }

此代码发送了向右箭头键，我想发送ALT + CTRL + RIGHT，我尝试了以下操作：

    public static void Forward()
    {
        Process[] processes = Process.GetProcessesByName("test");

        foreach (Process proc in processes)
        {
            PostMessage(proc.MainWindowHandle, WM_KEYDOWN, VK_CONTROL, 0);
            PostMessage(proc.MainWindowHandle, WM_KEYDOWN, VK_ALT, 0);
            PostMessage(proc.MainWindowHandle, WM_KEYDOWN, VK_RIGHT, 0);
        }
    }

但这行不通...

有任何想法吗？

我在使用RVM的Ubuntu 12.04,Ruby 1.9.3,Rails 3.2.8.

昨天我用Capistrano就好了,我重新启动了我的ubuntu,现在我正在尝试使用capistrano部署我得到这个:

$ cap deploy
/usr/lib/ruby/vendor_ruby/1.8/rubygems/custom_require.rb:36:in `gem_original_require': no such file to load -- rvm/capistrano (LoadError)
    from /usr/lib/ruby/vendor_ruby/1.8/rubygems/custom_require.rb:36:in `require'
    from /var/lib/gems/1.8/gems/capistrano-2.13.4/lib/capistrano/configuration/loading.rb:152:in `require'
    from ./config/deploy.rb:4:in `load'
    from /var/lib/gems/1.8/gems/capistrano-2.13.4/lib/capistrano/configuration/loading.rb:172:in `load_from_file'
    from /var/lib/gems/1.8/gems/capistrano-2.13.4/lib/capistrano/configuration/loading.rb:89:in `load'
    from /var/lib/gems/1.8/gems/capistrano-2.13.4/lib/capistrano/configuration/loading.rb:86:in `load'
    from /var/lib/gems/1.8/gems/capistrano-2.13.4/lib/capistrano/configuration/loading.rb:86:in `each'
    from /var/lib/gems/1.8/gems/capistrano-2.13.4/lib/capistrano/configuration/loading.rb:86:in `load'
    from Capfile:5:in `load'
    from /var/lib/gems/1.8/gems/capistrano-2.13.4/lib/capistrano/configuration/loading.rb:172:in `load_from_file'
    from /var/lib/gems/1.8/gems/capistrano-2.13.4/lib/capistrano/configuration/loading.rb:89:in `load'
    from /var/lib/gems/1.8/gems/capistrano-2.13.4/lib/capistrano/configuration/loading.rb:86:in `load'
    from /var/lib/gems/1.8/gems/capistrano-2.13.4/lib/capistrano/configuration/loading.rb:86:in `each'
    from /var/lib/gems/1.8/gems/capistrano-2.13.4/lib/capistrano/configuration/loading.rb:86:in `load'
    from /var/lib/gems/1.8/gems/capistrano-2.13.4/lib/capistrano/cli/execute.rb:65:in `load_recipes'
    from /var/lib/gems/1.8/gems/capistrano-2.13.4/lib/capistrano/cli/execute.rb:65:in `each'
    from /var/lib/gems/1.8/gems/capistrano-2.13.4/lib/capistrano/cli/execute.rb:65:in `load_recipes'
    from /var/lib/gems/1.8/gems/capistrano-2.13.4/lib/capistrano/cli/execute.rb:31:in `execute!'
    from …