创建使用其他用户控件的用户控件

Question

我有一个用户控件作为TrackBar，SelectedMin，Value和SelectedMax在Min和Max的范围内。

我现在想要创建另一个用户控件作为上述用户控件的一种shell，以便包含悬停标签以显示每个所选值的当前值。

我想在单独的用户控件中执行此操作，因为将所有内容向下移动以便为TrackBar用户控件中的值标签腾出空间似乎很痛苦。

这是我当前的CustomTrackBar.cs用户控件。对不起，它太乱了：

public partial class CustomTrackBar : UserControl
{

    #region variables
    private int min = 0;
    private int max = 1000;
    private int selectedMin = 0;
    private int selectedMax;
    private int value;

    private int sliderWidth = 2;
    #endregion

    #region accessors

    public int Min
    {
        get { return min; }
        set { min = value; Invalidate(); }
    }

    public int Max
    {
        get { return max; }
        set { max = value; Invalidate(); }
    }

    public int SelectedMin
    {
        get { return selectedMin; }
        set
        {
            selectedMin = value;
            if (AnythingChanged != null)
            {
                //SelectionChanged(this, null);
                AnythingChanged(this, null);
            }
            MinChanged = true;
            Invalidate();
        }
    }

    public int SelectedMax
    {
        get { return selectedMax; }
        set
        {
            selectedMax = value;
            if (AnythingChanged != null)
            {
                //SelectionChanged(this, null);
                AnythingChanged(this, null);
            }
            MaxChanged = true;
            Invalidate();
            MaxChanged = false;
        }
    }

    public int Value
    {
        get { return value; }
        set
        {
            this.value = value;
            if (AnythingChanged != null)
            {
                //ValueChanged(this, null);
                AnythingChanged(this, null);
            }
            ValueChanged = true;
            Invalidate();
        }
    }

    public int SliderWidth
    {
        get { return sliderWidth; }
        set
        {
            this.sliderWidth = value;
            Invalidate();
        }
    }

    public Boolean MinChanged
    {
        get; private set;
    }
    public Boolean ValueChanged
    {
        get; private set;
    }
    public Boolean MaxChanged
    {
        get; private set;
    }

    #endregion

    //Fired when SelectedMin or SelectedMax changes.
    //public event EventHandler SelectionChanged;

    //Fired when Value changes.
    //public event EventHandler ValueChanged;

    //Fired if anything changes
    public event EventHandler AnythingChanged;


    public CustomTrackBar()
    {
        //Set default values
        Value = (Max - Min) / 2;
        SelectedMax = Max;

        SliderWidth = SliderWidth / (Max - Min); //this line is horrible

        InitializeComponent();



        //Avoid flickering
        SetStyle(ControlStyles.AllPaintingInWmPaint, true);
        SetStyle(ControlStyles.OptimizedDoubleBuffer, true);

        //Events
        Paint += new PaintEventHandler(CustomTrackBar_Paint);
        MouseDown += new MouseEventHandler(CustomTrackBar_MouseDown);
        MouseMove += new MouseEventHandler(CustomTrackBar_MouseMove);
    }

    //Create a rectangle
    void CustomTrackBar_Paint(object sender, PaintEventArgs e)
    {
        //paint background in white
        e.Graphics.FillRectangle(Brushes.White, ClientRectangle);

        //Create a rectangle object
        Rectangle selectionRect = new Rectangle(
            0,
            0,
            Width,
            Height);

        /*
        Rectangle selectionRect = new Rectangle(
        (SelectedMin - Min) * Width / (Max - Min),
        15,
        (SelectedMax - selectedMin) * Width / (Max - Min),
        Height - 30);
        */

        //paint the rectangle object
        e.Graphics.FillRectangle(Brushes.GreenYellow, selectionRect);

        //Again how does this work?
        Rectangle firstFrameRect = new Rectangle(
            (SelectedMin - SliderWidth/2) * Width / (Max - Min),
            0,
            SliderWidth * Width / (Max - Min),
            Height
            );
        e.Graphics.FillRectangle(Brushes.DarkBlue, firstFrameRect);


        Rectangle lastFrameRect = new Rectangle(
            (SelectedMax - SliderWidth/2) * Width / (Max - Min),
            0,
            SliderWidth * Width / (Max - Min),
            Height
            );

         /*
            Rectangle lastFrameRect = new Rectangle(
            SelectedMax * Width / (Max - Min),
            0,
            5 * Width / (Max - Min),
            Height
            );
         */

        e.Graphics.FillRectangle(Brushes.OrangeRed, lastFrameRect);


        //draw a black frame around our control
        e.Graphics.DrawRectangle(Pens.Black, 0, 0, Width - 1, Height - 1);

        //draw a simple vertical line at the Value position
        e.Graphics.DrawLine(Pens.Black,
            (Value - Min) * Width / (Max - Min) - 5,
            0,
            (Value - Min) * Width / (Max - Min) - 5,
            Height);
    }

    void CustomTrackBar_MouseDown(object sender, MouseEventArgs e)
    {
        //check where the user clicked so we can decide which thumb to move
        int pointedValue = Min + e.X * (Max - Min) / Width;
        int distValue = Math.Abs(pointedValue - Value);
        int distMin = Math.Abs(pointedValue - SelectedMin);
        int distMax = Math.Abs(pointedValue - SelectedMax);
        int minDist = Math.Min(distValue, Math.Min(distMin, distMax));
        if (minDist == distValue)
            movingMode = MovingMode.MovingValue; //this should only move when video plays
        else if (minDist == distMin)
            movingMode = MovingMode.MovingMin;
        else
            movingMode = MovingMode.MovingMax;
        //call this to refreh the position of the selected thumb
        CustomTrackBar_MouseMove(sender, e);
    }

    void CustomTrackBar_MouseMove(object sender, MouseEventArgs e)
    {
        //if the left button is pushed, move the selected thumb
        if (e.Button != MouseButtons.Left)
            return;
        int pointedValue = Min + e.X * (Max - Min) / Width;
        if (movingMode == MovingMode.MovingValue)
        {
            if (pointedValue <= Max && pointedValue >= Min)
                Value = pointedValue;
        }
        else if (movingMode == MovingMode.MovingMin)
        {
            if (pointedValue < SelectedMax && pointedValue >= Min)
                SelectedMin = pointedValue;
        }
        else if (movingMode == MovingMode.MovingMax)
        {
            if (pointedValue > SelectedMin && pointedValue <= Max)
                SelectedMax = pointedValue;
        }
    }


    //To know which thumb is moving
    enum MovingMode { MovingValue, MovingMin, MovingMax }
    MovingMode movingMode;

    public String AllValues()
    {
        return String.Format("{0}\t{1}\t{2}", SelectedMin, Value, SelectedMax);
    }

}

这里是CustomTrackBar现在的样子。可以单击并拖动垂直的蓝色，黑色和红色线：

这是我想要的样子草图：

我真的不知道如何开始新的用户控制。我试图在新的用户控件中创建一个CustomTrackBar对象，但这似乎并没有绘制任何东西。

此外，它是否正确＆＃34;创建另一个用户控件以将片段添加到TrackBar？我应该坚持下去并在第一个用户控制中做所有事情吗？

感谢。

Answer 1

当您构建的新控件未绘制时，您应该首先验证它是否具有正确的非零维度，并且您没有覆盖绘图代码（您在CustomTrackBar_Paint中执行的操作）。除非您对坐标空间以及绘图代码的实际操作有很强的把握，否则您应该更喜欢使用自定义绘图，而不是自定义绘图。

我的意思是组合将控件拆分为具有多个内部控件的容器，所有这些控件都已存在于框架中。例如，您可以设置UserControl，背景和条形Panels以及数字Labels。正确定位和调整大小，在滑块值/ min / max / etc更改时更新。如果这样做，您可以简化代码，而不必触摸绘图代码。

这样的事情：

public partial class CustomTrackBar : Panel
{
    private Panel backdrop;
    private Panel minBar;
    private Panel maxBar;
    private Panel currentBar;
    private Label minDisplay;
    private Label maxDisplay;
    private Label currentDisplay;

    public CustomTrackBar()
    {
        InitializeComponent(); // This should almost always be first.
        backdrop = new Panel() {
            BackColor = Color.LightGreen,
            // set position, size, etc.
        };
        // add event handlers to backdrop...
        Controls.Add(backdrop);
        // repeat for minBar, maxBar, etc.

        SizeChanged += (sender, args) => {
            Update();
        };

        // ... remaining initialization logic.
    }

    private void Update()
    {
        // adjust the position and size of each inner control...
    }
}

只有在您完成此操作并测量了性能影响后，才能进行自定义绘图。这将允许您使用工作代码进行增量更改，而不是在黑暗中对其进行刺穿。