老吴编程笔记

月度归档： 2018 年 1 月

  • Entity framework 中比较日期 

    Entity framework 中比较日期 ，使用linq的写法：

    var totalCount = db.CallLog.Where(x => x.CallTime.Year == DateTime.Now.Year && x.CallTime.Month == DateTime.Now.Month && x.CallTime.Day == DateTime.Now.Day).Count();

    分别比较年月日，虽然不好看，但是可以正常工作。

  • EntityFramework Linq查询使用int.parse报错

    EntityFramework Linq 查询中不能使用int.parse，否则报错，报错信息如下：

    报错信息：LINQ to Entities does not recognize the method ‘Int32 Parse(System.String)’ method, and this method

    var data = from v in db.Vip
            join b in db.Business on v.BusinessId equals b.Id
            where v.Level == int.Parse(level) // 这样写会报错
            select new VipInfoModel
            {
                VipName = v.VipName,
                Level = v.Level.Value,
                BusinessId = v.BusinessId.Value,
                BusinessName = b.Name,
                DisplayName = b.DisplayName
            };

    解决方案：把int.parse拿到外面

    var _level = int.Parse(level);
var data = from v in db.Vip
            join b in db.Business on v.BusinessId equals b.Id
            where v.Level == _level
           select new VipInfoModel
            {
                VipName = v.VipName,
                Level = v.Level.Value,
                BusinessId = v.BusinessId.Value,
                BusinessName = b.Name,
                DisplayName = b.DisplayName
            };

  • 安卓4.4及4.4以上 全屏代码

    安卓4.4及4.4以上 全屏代码，加在onCreate中：

    //全屏开始
supportActionBar?.hide() // 隐藏标题栏
window.setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN) //设置全屏
//设置屏幕长亮
window.setFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON,
WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON)
setContentView(R.layout.activity_main)

// 这个组合不好用，当在触摸屏幕时还是会出现系统导航栏（home, back等）
val mUIFlag = (View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
or View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
or View.SYSTEM_UI_FLAG_LAYOUT_STABLE
or View.SYSTEM_UI_FLAG_LOW_PROFILE
or View.SYSTEM_UI_FLAG_FULLSCREEN
or View.SYSTEM_UI_FLAG_HIDE_NAVIGATION)

// 4.4以及上全屏
val mUIFlag2 =(
View.SYSTEM_UI_FLAG_LAYOUT_STABLE
or View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
or View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
or View.SYSTEM_UI_FLAG_HIDE_NAVIGATION // hide nav bar

or View.SYSTEM_UI_FLAG_FULLSCREEN // hide status bar

or View.SYSTEM_UI_FLAG_IMMERSIVE)

//取消全屏
val cancelFullScreenFlag = (View.SYSTEM_UI_FLAG_LAYOUT_STABLE
or View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
or View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN)

window.decorView.systemUiVisibility = mUIFlag2
// 全屏结束

    项目中的代码

    override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)

//全屏开始
supportActionBar?.hide() // 隐藏标题栏
window.setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN) //设置全屏
//设置屏幕长亮
window.setFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON,
WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON)
setContentView(R.layout.activity_main)

// 这个组合不好用，当在触摸屏幕时还是会出现系统导航栏（home, back等）
val mUIFlag = (View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
or View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
or View.SYSTEM_UI_FLAG_LAYOUT_STABLE
or View.SYSTEM_UI_FLAG_LOW_PROFILE
or View.SYSTEM_UI_FLAG_FULLSCREEN
or View.SYSTEM_UI_FLAG_HIDE_NAVIGATION)

// 4.4以及上全屏
val mUIFlag2 =(
View.SYSTEM_UI_FLAG_LAYOUT_STABLE
or View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
or View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
or View.SYSTEM_UI_FLAG_HIDE_NAVIGATION // hide nav bar

or View.SYSTEM_UI_FLAG_FULLSCREEN // hide status bar

or View.SYSTEM_UI_FLAG_IMMERSIVE)

//取消全屏
val cancelFullScreenFlag = (View.SYSTEM_UI_FLAG_LAYOUT_STABLE
or View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
or View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN)

window.decorView.systemUiVisibility = mUIFlag2
// 全屏结束


//注册onLongClick监听器
super.findViewById<LinearLayout>(R.id.changeBkgArea).setOnLongClickListener(PicOnLongClick())
super.findViewById<LinearLayout>(R.id.settingArea).setOnLongClickListener(OnLongClickSetting())

loadConfig()
    loadBackgroundImage()
    startGetCommandLoop()
}

  • 如何用SQL SERVER内置的函数把NULL转换成空字符串

    如何用SQL SERVER内置的函数把NULL转换成空字符串

    isnull(字段名,'')

    如果字段为null，会得到空字符串；如果字段不为null，则会得到字段值