Pb自制进度条

谁借莪１个温暖的怀抱￠ 2022-06-17 23:42 303阅读 0赞

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 PowerBuilder &nbsp; 是大家公认的、 &nbsp; 最佳的数据库前端开发工具之一，但一直以来，PB在用户界面的处理上十分单调，最明显的例子是，所有的窗口控件都不支持透明色即transparent &nbsp; 。PowerBuilder &nbsp; 7以前的版本没有提供进度条，造成大多数程序员总是自己在程序中利用两个矩形控件(Rectangle)进行编程产生进度效果。但是这样一来，进度条中的进度百分比就没有了，如果再加上一个静态文本作为百分比显示，由于statictext控件没有透明色，进度条的百分比显示无法与进度条进行重叠，只得在进度条外的其它位置放置一statictext控件用以显示进度情况，这样即浪费了空间，又不美观。 &nbsp; 在网上也曾看到过解决的方法，主要是利用了数据窗口中控件可以透明处理的特征，但总感觉美中不足，数据窗口是一种重型控件，要占用大量的系统资源，能不能用其他更简单的方法解决上述问题呢？ &nbsp; 上述问题的关键在于文本的输出背景要透明，我们知道：Windows系统本身提供了大量的底层API功能函数供上层的应用程序调用，文本的输出该是最基本的吧，所以Windows一定能够解决文本背景透明输出的问题。仔细查找API帮助，果然找到相关的函数，于是问题迎刃而解。 &nbsp; 下面列出主要的声明和对象实现的主要程序段: &nbsp; 新建一可视定制用户对象uo_progressbar,在其中放置两个矩形控件(Rectangle)，分别命名为：r_back &nbsp; 和 &nbsp; r_front。定义实例变量如下： &nbsp; ulong &nbsp; iul_ihDC &nbsp; //保存可视定制用户对象的DC句柄 &nbsp; real &nbsp; ir_step &nbsp; //根据对象宽度计算出来的步进值 &nbsp; integer &nbsp; ii_x, &nbsp; ii_y &nbsp; //根据对象宽度和高度计算出来的文本输出位置 &nbsp; 声明Local &nbsp; external &nbsp; functions如下： &nbsp; Function &nbsp; ulong &nbsp; GetDC &nbsp; (ulong &nbsp; hWnd) &nbsp; Library &nbsp; "USER32.DLL " &nbsp; Function &nbsp; boolean &nbsp; TextOut &nbsp; (ulong &nbsp; hdcr, &nbsp; integer &nbsp; stx, &nbsp; integer &nbsp; sty, &nbsp; ref &nbsp; string &nbsp; lpString, &nbsp; long &nbsp; nCount) &nbsp; Library &nbsp; "GDI32.DLL " &nbsp; Alias &nbsp; for &nbsp; "TextOutA " &nbsp; Function &nbsp; int &nbsp; SetBkMode &nbsp; (ulong &nbsp; hdcr, &nbsp; integer &nbsp; mode) &nbsp; Library &nbsp; "GDI32.DLL " &nbsp; 在对象的constructor事件中输入以下代码： &nbsp; integer &nbsp; li_width, &nbsp; li_height &nbsp; //根据对象变框计算宽高 &nbsp; CHOOSE &nbsp; CASE &nbsp; this.BorderStyle &nbsp; CASE &nbsp; StyleLowered!,StyleRaised! &nbsp; li_width &nbsp; = &nbsp; this.width &nbsp; - &nbsp; PixelsToUnits(4, &nbsp; XPixelsToUnits!) &nbsp; li_height &nbsp; = &nbsp; this.height &nbsp; - &nbsp; PixelsToUnits(4, &nbsp; YPixelsToUnits!) &nbsp; CASE &nbsp; StyleBox!,StyleShadowBox! &nbsp; li_width &nbsp; = &nbsp; this.width &nbsp; - &nbsp; PixelsToUnits(2, &nbsp; XPixelsToUnits!) &nbsp; li_height &nbsp; = &nbsp; this.height &nbsp; - &nbsp; PixelsToUnits(2, &nbsp; XPixelsToUnits!) &nbsp; CASE &nbsp; Else &nbsp; li_width &nbsp; = &nbsp; this.width &nbsp; li_height &nbsp; = &nbsp; this.height &nbsp; END &nbsp; CHOOSE &nbsp; r_back.width &nbsp; = &nbsp; li_width &nbsp; r_front.height &nbsp; = &nbsp; li_height &nbsp; r_front.width &nbsp; = &nbsp; 0 &nbsp; r_back.height &nbsp; = &nbsp; li_height &nbsp; //计算百分比文本输出的位置使其在水平和垂直方向上居中 &nbsp; ii_x &nbsp; = &nbsp; UnitsToPixels(li_width, &nbsp; XUnitsToPixels!)/2 &nbsp; - &nbsp; 16 &nbsp; ii_y &nbsp; = &nbsp; ( &nbsp; UnitsToPixels(li_height, &nbsp; YUnitsToPixels!) &nbsp; - &nbsp; 16 &nbsp; )/2 &nbsp; ir_step &nbsp; = &nbsp; li_width/100 &nbsp; //计算步进值 &nbsp; iul_ihDC &nbsp; = &nbsp; GetDC( &nbsp; handle(this) &nbsp; ) &nbsp; //获得对象DC句柄，用于API调用 &nbsp; SetBkMode &nbsp; (iul_ihdc, &nbsp; 1 &nbsp; ) &nbsp; //设置文本输出背景色透明 &nbsp; return &nbsp; 0 &nbsp; 为对象写一个函数：of_setposition, &nbsp; //功能：根据参数改变进度显示 &nbsp; //参数：integer &nbsp; ai_percent &nbsp; //返回：无 &nbsp; string &nbsp; ls_msg &nbsp; integer &nbsp; li_x &nbsp; If &nbsp; ai_percent &nbsp; &lt;= &nbsp; 100 &nbsp; and &nbsp; ai_percent &nbsp; &lt; &nbsp; 0 &nbsp; then &nbsp; SetRedraw(FALSE) &nbsp; li_x= "ai_percent*ir_step " &nbsp; r_back.x= "li_x " &nbsp; r_front.width= "li_x " &nbsp; ls_msg= "string( " &nbsp; ai_percent &nbsp; )+ "% " &nbsp; SetRedraw(True) &nbsp; TextOut &nbsp; (iul_ihdc, &nbsp; ii_x, &nbsp; ii_y, &nbsp; ls_msg, &nbsp; len( &nbsp; ls_msg &nbsp; ) &nbsp; ) &nbsp; End &nbsp; If &nbsp; 当然你还可以编写函数改变进度条中的前景色背景色和文本颜色，这里不再赘述。 
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