C# 将静态方法添加到当前自定义类

我有自定义进度条（是带有文本的进度条）

自定义条码：

public enum ProgressBarDisplayText
    {
        Percentage,
        CustomText
    }

    public class CustomProgressBar : ProgressBar
    {


        [DllImportAttribute("uxtheme.dll")]
        private static extern int SetWindowTheme(IntPtr hWnd, string appname, string idlist);

        protected override void OnHandleCreated(EventArgs e)
        {
            SetWindowTheme(this.Handle, "", "");
            base.OnHandleCreated(e);
        }

        //Property to set to decide whether to print a % or Text
        public ProgressBarDisplayText DisplayStyle { get; set; }

        //Property to hold the custom text
        public String CustomText { get; set; }

        public CustomProgressBar()
        {
            // Modify the ControlStyles flags
            //http://msdn.microsoft.com/en-us/library/system.windows.forms.controlstyles.aspx
            SetStyle(ControlStyles.UserPaint | ControlStyles.AllPaintingInWmPaint, true);
            SetStyle(ControlStyles.OptimizedDoubleBuffer, true);
        }

        protected override void OnPaint(PaintEventArgs e)
        {
            Rectangle rect = ClientRectangle;
            Graphics g = e.Graphics;

            ProgressBarRenderer.DrawHorizontalBar(g, rect);
            rect.Inflate(-3, -3);
            if (Value > 0)
            {
                // As we doing this ourselves we need to draw the chunks on the progress bar
                Rectangle clip = new Rectangle(rect.X, rect.Y, (int)Math.Round(((float)Value / Maximum) * rect.Width), rect.Height);
                ProgressBarRenderer.DrawHorizontalChunks(g, clip);
            }

            // Set the Display text (Either a % amount or our custom text
            int percent = (int)(((double)this.Value / (double)this.Maximum) * 100);
            string text = DisplayStyle == ProgressBarDisplayText.Percentage ? percent.ToString() + '%' : CustomText;

            //string text = DisplayStyle == ProgressBarDisplayText.Percentage ? Value.ToString() + '%' : CustomText;


            using (Font f = new Font(FontFamily.GenericSerif, 10, FontStyle.Bold))
            {

                SizeF len = g.MeasureString(text, f);
                // Calculate the location of the text (the middle of progress bar)
                // Point location = new Point(Convert.ToInt32((rect.Width / 2) - (len.Width / 2)), Convert.ToInt32((rect.Height / 2) - (len.Height / 2)));
                Point location = new Point(Convert.ToInt32((Width / 2) - len.Width / 2), Convert.ToInt32((Height / 2) - len.Height / 2));
                // The commented-out code will centre the text into the highlighted area only. This will centre the text regardless of the highlighted area.
                // Draw the custom text
                g.DrawString(text, f, Brushes.Black, location);
            }

        }
    }

现在我想改变进度条的颜色，所以我看到了这个

所以我尝试添加到我的代码中

  [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = false)]
  static extern IntPtr SendMessage(IntPtr hWnd, uint Msg, IntPtr w, IntPtr l);
    public static void SetState(this ProgressBar pBar, int state)
    {
        SendMessage(pBar.Handle, 1040, (IntPtr)state, IntPtr.Zero);
    }

但是正如您所看到的，这段代码是用于扩展方法的，但是我当前的

CustomProgressBar

继承了

ProgressBar

，它不允许使用静态类。所以它让我：

扩展方法必须在非泛型静态类中定义

---

如何将此方法添加到当前类中？关于

这是一种扩展方法，需要在静态类中使用。如果只想让它在现有的非静态类中工作，只需去掉第一个参数上的

this

：

[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = false)]
static extern IntPtr SendMessage(IntPtr hWnd, uint Msg, IntPtr w, IntPtr l);

public static void SetState(ProgressBar pBar, int state)
{
    SendMessage(pBar.Handle, 1040, (IntPtr)state, IntPtr.Zero);
}

---

参数仍然可以是

ProgressBar

类型，因为

CustomProgressBar

继承自该参数。

扩展方法必须在

static

类中定义。通常我只是创建一个

公共静态类扩展{}

并将它们添加到那里。如果要将它们添加到当前类中，可以从第一个参数中删除

this

，然后传入控件的实例。我复制粘贴了你的代码，但我不明白为什么？你说摆脱这个是什么意思，我看到你的代码和我的一样，有什么区别？你的有这个ProgressBar pBar，我的只有ProgressBar pBar。