如何触发轨迹栏的OnValueChanged事件 [英] how to trigger the trackbar's OnValueChanged event

问题描述

我绘制了trackbar组件并将其命名为cumstomtrackbar，它继承自trackbar类。

但我发现customtrackbar无法触发OnValueChanged事件，如何触发它？

一些相关的代码如下：

I drawed trackbar component and named it as cumstomtrackbar,it inherit from trackbar class.
But I find that the customtrackbar can't tigger OnValueChanged event,how to trigger it ?
some releated code as below:

  public class CustomTrackBar:System.Windows.Forms.TrackBar
 {
        protected override void WndProc(ref Message m)
        {
            switch (m.Msg)
            {
                case WM.WM_PAINT:
                    if (true)
                    {
                        PAINTSTRUCT ps = new PAINTSTRUCT();
                        BeginPaint(m.HWnd, ref ps);
                        DrawTrackBar(m.HWnd);
                        ValidateRect(m.HWnd, ref ps.rcPaint);
                        EndPaint(m.HWnd, ref ps);
                    }
                    else
                    {
                        base.WndProc(ref m);
                    }
                    break;
                default:
                    base.WndProc(ref m);
                    break;
            }
        }
}

推荐答案

首先：为什么要覆盖WndProc？我建议覆盖OnPaint方法。

然后：您的自定义控件应该具有像Base-Control这样的Value-Property。现在......如果您的值发生变化（将其与last_Value - 另一个变量 - 可能在您的Value-Property的Setter中进行比较），则调用OnValueChanged-Method。此方法将引发事件。

At first : why do you override the WndProc ? I would suggest to override the OnPaint-method.
Then : your customized Control should have a Value-Property like the Base-Control. Now ... if your value changes (compare it with the last_Value - another variable - perhaps in the Setter of your Value-Property) you call the OnValueChanged-Method. This Method will raise the Event.

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