滑块 - 捕捉到点并拖动事件答案

【问题标题】：Slider - snap to point and dragging with events滑块 - 捕捉到点并拖动事件
【发布时间】：2013-01-27 18:09:07
【问题描述】：

当滑块的拇指被拖动到一个新值或单击到一个新值时，我需要触发一个事件。我只希望在值更改时发生此事件是这两种方式，使用鼠标，因此 ValueChanged 事件将不起作用。

【问题讨论】：

【解决方案1】：

你可以试试这个小技巧

首先您需要将 UpdateSourceTrigger 设置为 Explicit

<Slider Minimum="0"
        Thumb.DragStarted="Slider_DragStarted"
        Thumb.DragCompleted="Slider_DragCompleted"
        Maximum="{Binding YourMaxBinding, Mode=OneWay}"
        Value="{Binding CurrentPosition, Mode=TwoWay, UpdateSourceTrigger=Explicit}" />

后面的代码

private void Slider_DragStarted(object sender, System.Windows.Controls.Primitives.DragStartedEventArgs e) {
    // try to prevent updating slider position from your view model
    yourViewModel.DontUpdateSliderPosition = true;
}

private void Slider_DragCompleted(object sender, System.Windows.Controls.Primitives.DragCompletedEventArgs e) {
    BindingExpression be = ((Slider)sender).GetBindingExpression(RangeBase.ValueProperty);
    if (be != null) {
      be.UpdateSource();
    }
    yourViewModel.DontUpdateSliderPosition = false;
}

在您的视图模型中编写代码

private bool _dontUpdateSliderPosition;
public bool DontUpdateSliderPosition {
    get {
        return _dontUpdateSliderPosition;
    }
    set {
        if (Equals(value, _dontUpdateSliderPosition)) {
            return;
        }
        _dontUpdateSliderPosition = value;
        yourPropertyChangedFunc("DontUpdateSliderPosition");
    }
}

private int _currentPosition;
public int CurrentPosition {
    get {
        return _currentPosition;
    }
    set {
        if (Equals(value, _currentPosition)) {
            return;
        }
        _currentPosition = value;
        yourPropertyChangedFunc("CurrentPosition");
    }
}

private CodeBehindFuncToChangeTheSliderPosition(){
    if (!DontUpdateSliderPosition) {
        CurrentPosition = theNewPosition;
    }
}

希望对你有帮助

【讨论】：