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Asked:2022-04-15 12:26:59 +0000 UTC2022-04-15 12:26:59 +0000 UTC

在 WinForms C# 覆盖中更改矩形的颜色

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如何更改 Rectangle 的颜色并在叠加层中更新它？我目前使用这种颜色更改方法：

static public Color w = Color.FromArgb(255, 35, 35, 35);
static public Color a = Color.FromArgb(255, 35, 35, 35);
static public Color s = Color.FromArgb(255, 35, 35, 35);
static public Color d = Color.FromArgb(255, 35, 35, 35);
static public void Draw(System.Drawing.Graphics g, int size, int x, int y)
{
    // Background
    Brush bBrushW = new SolidBrush(w);
    Brush bBrushA = new SolidBrush(a);
    Brush bBrushS = new SolidBrush(s);
    Brush bBrushD = new SolidBrush(d);
    ...

但是在更改颜色时，对象会保留其旧颜色，我在计时器中以类似的方式更改颜色：

private void Letters_Tick(object sender, EventArgs e)
{
    // Keystokes W
    if (Input.isPressed(Keys.W) != 0)
    {
        Keystokes.w = Color.FromArgb(255, 255, 0, 0);
    } else
    {
        Keystokes.w = Color.FromArgb(255, 35, 35, 35);
    }
    ...

该函数Draw仅在 Paint 表单中调用一次：

private void Overlay_Paint(object sender, PaintEventArgs e)
{
    g = e.Graphics;
    Keystokes.Draw(g, 50, Width - 350, 250);
}

如何使它以最小的负载更新颜色？

c#

1 个回答

  1. Best Answer

    每次需要更新颜色时：

    Overlay.Invalidate();

    或者如果您知道要更新的区域的坐标更好：

    Rectangle area;  
Overlay.Invalidate(area);

    更好的是，扔掉计时器并留意键盘：

    using System.Runtime.InteropServices;

private delegate IntPtr LowLevelKeyboardProc(int nCode, IntPtr wParam, IntPtr lParam);
private LowLevelKeyboardProc _proc = hookProc;
private static IntPtr hhook = IntPtr.Zero;

[DllImport("user32.dll")]
static extern IntPtr SetWindowsHookEx(int idHook, LowLevelKeyboardProc callback, IntPtr hInstance, uint threadId);
[DllImport("user32.dll")]
static extern bool UnhookWindowsHookEx(IntPtr hInstance);
[DllImport("kernel32.dll")]
static extern IntPtr LoadLibrary(string lpFileName);

const int WH_KEYBOARD_LL = 13; // Номер глобального LowLevel-хука на клавиатуру
const int
   WM_KEYDOWN = 0x100,       //Key down
   WM_KEYUP = 0x101;         //Key up

//функция, принимающая нажатия
public IntPtr hookProc(int code, IntPtr wParam, IntPtr lParam)
{
    if (code >= 0 && wParam == (IntPtr)WM_KEYDOWN || code >= 0 && wParam == (IntPtr)260)
    {
        int vkCode = Marshal.ReadInt32(lParam); //Получить код клавиши
        this.Text = "Нажата клавиша: "+vkCode; //this == form1
    }
    if (code >= 0 && wParam == (IntPtr)WM_KEYUP || code >= 0 && wParam == (IntPtr)260)
    {
        int vkCode = Marshal.ReadInt32(lParam); //Получить код клавиши
        this.Text = "Отжата клавиша: " + vkCode; //this == form1
    }
    return IntPtr.Zero;
}

//при загрузке формы подключаем слежение
form1.Load += (s,a) =>
{
    IntPtr hInstance = LoadLibrary("User32");
    hhook = SetWindowsHookEx(WH_KEYBOARD_LL, _proc, hInstance, 0);
};

//при закрытии формы отключаем слежение
form1.FormClosing += (s,a) =>
{
    UnhookWindowsHookEx(hhook); //Остановить хук
};

    代替“this.Text = ... vkCode; //this == form1” - 替换您需要的键上的 if-else，或者更确切地说是 func(int vkCode) 函数，在该函数中使用调用 Invalidate()

    示例取自此处：https ://www.cyberforum.ru/post9660429.html

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