Question

任何人都可以一步一步地向我解释这个功能吗？我的另一个代码不起作用，这就是为什么我认为我不理解这个功能。下面的代码是误解函数。

＆＃13;

class MyView: NSView {

    //add observer on awake from nib
    //works fine
    override func awakeFromNib() {
        if let win = self.window {
            win.addObserver(self, forKeyPath: Notification.Name.NSWindowDidBecomeKey.rawValue, options: .new, context: nil)
        }
    }

    //remove observer on dealloc
    //allso works fine
    deinit {
        if let win = self.window {
            win.removeObserver(self, forKeyPath: Notification.Name.NSWindowDidBecomeKey.rawValue)
        }
    }

    //never gets called
    override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
        Swift.print(keyPath ?? "")
        Swift.print("worked!")
    }

    override func draw(_ dirtyRect: NSRect) {
        NSColor.blue.set()
        NSBezierPath.fill(dirtyRect)
    }
}

＆＃13;

以下是我理解函数的方法（连接完成MS SQL）。不知道究竟是什么意思返回true，是否与sqlsrv_fetch_array相同？

＆＃13;

<?php

public function sql_exec($query)
    {
        $query = trim($query);
        
        if($this->result = db_query($query, $this->con_id)) 
        {
            $this->row_count = db_num_rows($this->result);
            return TRUE; //what it returns exactly??
        }

    }
?>

＆＃13;

Answer 1

<?php

public function sql_exec($query)
    {
        $query = trim($query);

        if($this->result = db_query($query, $this->con_id)) 
        {
            $this->row_count = db_num_rows($this->result);
            return TRUE; //what it returns exactly??
        }

    }
?>

如果查询成功执行，则上面的代码返回BOOLEAN值TRUE。但似乎在你给出的例子中没有调用该函数。

在php中对小功能的误解

1 个答案: