如何在键盘按键被按下时更改TrackBar控制操作？

Question

TrackBar控制器的改变方向与它被改变的方向相反： page-up/page-down/arrow-up/arrow-down。 Why does the Trackbar value decrease on arrow up/PgUp?

有没有办法解决/扭转这种行为：

这细节在这里被提及？

Answer 1

唉......我从来没有注意到过。这里是我的建议刺的@Hans：

public class MyTrackBar : TrackBar 
{ 

    protected override bool ProcessCmdKey(ref Message msg, Keys keyData) 
    { 
     switch (keyData) 
     { 
      case Keys.Up: 
       this.Value = Math.Min(this.Value + this.SmallChange, this.Maximum); 
       return true; 

      case Keys.Down: 
       this.Value = Math.Max(this.Value - this.SmallChange, this.Minimum); 
       return true; 

      case Keys.PageUp: 
       this.Value = Math.Min(this.Value + this.LargeChange, this.Maximum); 
       return true; 

      case Keys.PageDown: 
       this.Value = Math.Max(this.Value - this.LargeChange, this.Minimum); 
       return true; 
     } 
     return base.ProcessCmdKey(ref msg, keyData); 
    } 

} 

Answer 2

Idle_Mind的回答是不错的，实际上帮助了我，但它有一个缺点，那就是它可以防止控制从提高Scroll和ValueChanged事件时最多 ，Down，PageUp或PageDown被点击。所以，这里是我的版本：

public class ProperTrackBar : TrackBar 
{ 

    protected override bool ProcessCmdKey(ref Message msg, Keys keyData) 
    { 
     int oldValue = this.Value; 
     switch (keyData) 
     { 
      case Keys.Up: 
       this.Value = Math.Min(this.Value + this.SmallChange, this.Maximum); 
       break; 
      case Keys.Down: 
       this.Value = Math.Max(this.Value - this.SmallChange, this.Minimum); 
       break; 
      case Keys.PageUp: 
       this.Value = Math.Min(this.Value + this.LargeChange, this.Maximum); 
       break; 
      case Keys.PageDown: 
       this.Value = Math.Max(this.Value - this.LargeChange, this.Minimum); 
       break; 
      default: 
       return base.ProcessCmdKey(ref msg, keyData); 
     } 

     if (Value != oldValue) 
     { 
      OnScroll(EventArgs.Empty); 
      OnValueChanged(EventArgs.Empty); 
     } 
     return true; 
    } 
}