C# winform绘制Chart曲线图滚轮放大缩小方法，以及鼠标滚轮无效解决办法

阳光穿透心脏的1/2处 2024-02-05 21:26 26阅读 0赞

### C\# winform绘制Chart曲线图滚轮放大缩小方法，以及鼠标滚轮无效解决办法 ###

滚动方法如下

private void chart1_MouseWheel(object sender, MouseEventArgs e)
            {
        
                //将鼠标位置转换到chart控件坐标系中
                double mouse_x = chart1.ChartAreas[0].AxisX.PixelPositionToValue(e.X);
                double mouse_y = chart1.ChartAreas[0].AxisY.PixelPositionToValue(e.Y);
                //限制鼠标位置在chart的视图区内
                if (mouse_x < chart1.ChartAreas[0].AxisX.ScaleView.ViewMaximum
                    && mouse_x > chart1.ChartAreas[0].AxisX.ScaleView.ViewMinimum
                    && mouse_y < chart1.ChartAreas[0].AxisY.ScaleView.ViewMaximum
                    && mouse_y > chart1.ChartAreas[0].AxisY.ScaleView.ViewMinimum)
                {
        
                    double x_new_size = 0;//X轴的新ScaleView.Size值
                    if (e.Delta > 0)//滚轮向上放大
                    {
        
                        if (chart1.ChartAreas[0].AxisX.ScaleView.Size > 0)//设置最大放大值
                        {
        
                            x_new_size = chart1.ChartAreas[0].AxisX.ScaleView.Size * 0.95;//放大5%
                        }
                    }
                    else//滚轮向下缩小
                    {
        
                        if (chart1.ChartAreas[0].AxisX.ScaleView.Size < (chart1.ChartAreas[0].AxisX.Maximum - chart1.ChartAreas[0].AxisX.Minimum))//不能无限缩小，缩小的极限就是显示全图
                        {
        
                            x_new_size = chart1.ChartAreas[0].AxisX.ScaleView.Size * 1.05;//缩小5%
                            if (x_new_size >= (chart1.ChartAreas[0].AxisX.Maximum - chart1.ChartAreas[0].AxisX.Minimum))//最大的Size就是整个Y轴
                            {
        
                                x_new_size = chart1.ChartAreas[0].AxisX.Maximum - chart1.ChartAreas[0].AxisX.Minimum;
                            }
                        }
                    }
                    if (x_new_size > 0)
                    {
        
                        double x_mousenew;
                        double x_mouseold = chart1.ChartAreas[0].AxisX.PixelPositionToValue(e.X);
                        chart1.ChartAreas[0].AxisX.ScaleView.Size = x_new_size;
                        x_mousenew = chart1.ChartAreas[0].AxisX.PixelPositionToValue(e.X);
                        double newposition = x_mouseold - x_mousenew;
                        chart1.ChartAreas[0].AxisX.ScaleView.Position += newposition;
                        //限制视图在最大最小值之间，防止视图溢出
                        if (chart1.ChartAreas[0].AxisX.ScaleView.ViewMinimum < chart1.ChartAreas[0].AxisX.Minimum)
                            chart1.ChartAreas[0].AxisX.ScaleView.Position = chart1.ChartAreas[0].AxisX.Minimum;
                        if (chart1.ChartAreas[0].AxisX.ScaleView.ViewMaximum > chart1.ChartAreas[0].AxisX.Maximum)
                            chart1.ChartAreas[0].AxisX.ScaleView.Position = chart1.ChartAreas[0].AxisX.Maximum - (chart1.ChartAreas[0].AxisX.ScaleView.ViewMaximum - chart1.ChartAreas[0].AxisX.ScaleView.ViewMinimum);
                    }
                }
            }

`解决办法：`需要关注图表控件，以便触发鼠标滚轮事件。可以在鼠标进入控件时设置焦点，并在鼠标离开时将焦点返回给父控件。  
![在这里插入图片描述][2060b85d6a7e48109e374347724d2eb3.png]

private void chart1_MouseLeave(object sender, EventArgs e)
            {
        
                if (chart1.Focused)
                    chart1.Parent.Focus();
            }
    
            private void chart1_MouseEnter(object sender, EventArgs e)
            {
        
                if (!chart1.Focused)
                    chart1.Focus();
            }

[2060b85d6a7e48109e374347724d2eb3.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/01/30/40695b3a1b65402ba930c81398a19fe5.png