Winform控件優(yōu)化Paint事件實(shí)現(xiàn)圓角組件及提取繪制圓角的方法

更新時(shí)間：2022年08月29日 09:04:16 作者：代碼迷途

這篇文章主要介紹了Winform控件優(yōu)化Paint事件實(shí)現(xiàn)圓角組件及提取繪制圓角的方法，Windows?11下所有控件已經(jīng)默認(rèn)采用圓角，其效果更好、相對(duì)有著更好的優(yōu)化，只是這是默認(rèn)的行為，無(wú)法進(jìn)一步自定義，更多詳情需要的小伙伴可以參考下面文章內(nèi)容

前言

Windows 11下所有控件已經(jīng)默認(rèn)采用圓角，其效果更好、相對(duì)有著更好的優(yōu)化，只是這是默認(rèn)的行為，無(wú)法進(jìn)一步自定義。

注意兩點(diǎn)：

Paint事件方法中實(shí)現(xiàn)圓角控件不要通過(guò)事件參數(shù)e.ClipRectangle獲取控件區(qū)域范圍
注意設(shè)置控件背景透明（雖然Winform中的透明不是完全透明，

實(shí)現(xiàn)圓角控件比較好的一個(gè)思路是在控件的Paint事件中進(jìn)行繪制，不太好的地方在于每次實(shí)現(xiàn)時(shí)都要添加事件處理，且不能在設(shè)計(jì)器中實(shí)時(shí)看到效果。

只要有Paint事件的組件都實(shí)現(xiàn)繪制圓角【如果沒(méi)有，也可以通過(guò)將控件放在Panel中，借助Panel的圓角實(shí)現(xiàn)】。

Paint事件中實(shí)現(xiàn)圓角控件

注意：由于控件在Paint事件方法中進(jìn)行了重新繪制，因此文本也被覆蓋了，需要處理文本的繪制顯示

新建項(xiàng)目 CustomControlRound，窗體中添加兩個(gè)Panel、三個(gè)Button、一個(gè)Label控件。button設(shè)置Flat樣式、邊框?yàn)?。

然后在Paint事件方法中調(diào)用繪制圓角區(qū)域的方法（具體代碼參見(jiàn)下一部分的擴(kuò)展方法），具體如下：

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();

        panel1.Paint += Panel1_Paint;
        panel2.Paint += Panel2_Paint;

        panel1.BackColor = panel2.BackColor = Color.Transparent;

        button1.Paint += Button1_Paint;
        button1.FlatStyle = FlatStyle.Flat;
        button1.FlatAppearance.BorderSize = 0;
        button1.FlatAppearance.MouseDownBackColor = Color.Transparent;
        button1.FlatAppearance.MouseOverBackColor = Color.Transparent;
        button1.FlatAppearance.CheckedBackColor = Color.Transparent;


        button2.Paint += Button1_Paint;
        button2.FlatStyle = FlatStyle.Flat;
        button2.FlatAppearance.BorderSize = 0;
        //button2.FlatAppearance.BorderColor = SystemColors.ButtonFace;
        button2.FlatAppearance.MouseDownBackColor = Color.Transparent;
        button2.FlatAppearance.MouseOverBackColor = Color.Transparent;
        button2.FlatAppearance.CheckedBackColor = Color.Transparent;

        button3.Paint += Button1_Paint;
        button3.FlatStyle = FlatStyle.Flat;
        button3.FlatAppearance.BorderSize = 0;
        //button3.FlatAppearance.BorderColor = SystemColors.ButtonFace;
        button3.FlatAppearance.MouseDownBackColor = Color.Transparent;
        button3.FlatAppearance.MouseOverBackColor = Color.Transparent;
        button3.FlatAppearance.CheckedBackColor = Color.Transparent;

        label1.Paint += Label1_Paint;
        label1.BackColor = Color.Transparent;
    }

    private void Label1_Paint(object sender, PaintEventArgs e)
    {
        var l = (Label)sender;
        // e.Graphics.DrawRoundRectAndCusp(e.ClipRectangle,  18, Color.FromArgb(180, 200, 210), Color.FromArgb(120, 120, 100)); // 不推薦
        e.Graphics.DrawRoundRectAndCusp(new Rectangle(0,0, l.Width,l.Height),  18, Color.FromArgb(180, 200, 210), Color.FromArgb(120, 120, 100));
    }

    private void Button1_Paint(object sender, PaintEventArgs e)
    {
        var btn = (Button)sender;
        e.Graphics.DrawRoundRectAndCusp(new Rectangle(0, 0, btn.Width, btn.Height), 18, Color.FromArgb(0, 122, 204), Color.FromArgb(8, 39, 57));

        ((Button)sender).NotifyDefault(false); // 去除窗體失去焦點(diǎn)時(shí)最新激活的按鈕邊框外觀樣式
    }

    private void Panel1_Paint(object sender, PaintEventArgs e)
    {
        var panel = sender as Panel;
        var rect=e.Graphics.DrawRoundRectAndCusp(new Rectangle(0, 0, panel.Width, panel.Height), 18, Color.FromArgb(90, 143, 0), Color.FromArgb(41, 67, 0),true, rectAlign);
    }

    private void Panel2_Paint(object sender, PaintEventArgs e)
    {
        var panel = sender as Panel;
        var rect = e.Graphics.DrawRoundRectAndCusp(new Rectangle(0, 0, panel.Width, panel.Height), 18, Color.FromArgb(113, 113, 113), Color.FromArgb(0, 0, 0));
    }
}

查看效果：

在Paint事件中不需要調(diào)用 base.OnPaint(e);，只有在繼承控件重寫(xiě)OnPaint方法時(shí)，才應(yīng)該(在函數(shù)方法開(kāi)始時(shí))調(diào)用base.OnPaint(e);。

提取繪制圓角矩形和旁邊小尖角的代碼為擴(kuò)展方法

介紹

下面是提取的擴(kuò)展方法，對(duì)源代碼進(jìn)行了修改和優(yōu)化。

1、可繪制漸變背景色、指定背景色、指定畫(huà)刷繪制的背景；可指定漸變背景的方向
2、指定圓角半徑的繪制，如果半徑小于等于0，將繪制直角矩形。
3、指定三角小尖，默認(rèn)不繪制；指定三角小尖的位置，可供八個(gè)位置選擇
4、三角小尖的大小，目前感覺(jué)作為參數(shù)傳遞不夠靈活，如果需要調(diào)整可直接從代碼中修改，主要修改部分為：

// 尖角的大小 默認(rèn)為 開(kāi)始位置為_(kāi)radius 底邊為20，高度為13的等腰三角形
var cuspHemlineStart = _radius;
var cuspHemlineLength = 20;
var cuspHeight = 13;

擴(kuò)展方法

擴(kuò)展方法代碼如下，將其放在namespace System.Drawing.Drawing2D下，可直接方便的從Graphics對(duì)象調(diào)用。

/// <summary>
/// 繪制可漸變的圓角矩形，并指定是否有三角小尖及其位置
/// </summary>
/// <param name="g"></param>
/// <param name="rectangle">矩形區(qū)域</param>
/// <param name="_radius">圓角半徑</param>
/// <param name="begin_bgcolor">背景漸變開(kāi)始色</param>
/// <param name="end_bgcolor">背景漸變結(jié)束色</param>
/// <param name="cusp">是否有三角小尖，默認(rèn)無(wú)</param>
/// <param name="rectAlign">三角小尖的位置，默認(rèn)右上</param>
/// <param name="gradientMode">漸變模式，默認(rèn)垂直方向漸變</param>
public static void DrawRoundRectAndCusp(this Graphics g, Rectangle rectangle, int _radius, Color begin_bgcolor, Color end_bgcolor, bool cusp = false, RectangleAlign rectAlign= RectangleAlign.RightTop, LinearGradientMode gradientMode = LinearGradientMode.Vertical)
{
    ////抗鋸齒 等模式在Graphics外層自定義設(shè)置
    //g.SmoothingMode = SmoothingMode.AntiAlias;
    //漸變填充
    LinearGradientBrush linearGradientBrush = new LinearGradientBrush(rectangle, begin_bgcolor, end_bgcolor, gradientMode);
    g.DrawRoundRectAndCusp(rectangle, _radius, linearGradientBrush, cusp, rectAlign);
}

/// <summary>
/// 繪制指定背景的圓角矩形，并指定是否有三角小尖及其位置
/// </summary>
/// <param name="g"></param>
/// <param name="rectangle">矩形區(qū)域</param>
/// <param name="_radius">圓角半徑</param>
/// <param name="bgcolor">指定背景色</param>
/// <param name="cusp">是否有三角小尖，默認(rèn)無(wú)</param>
/// <param name="rectAlign">三角小尖的位置，默認(rèn)右上</param>
public static void DrawRoundRectAndCusp(this Graphics g, Rectangle rectangle, int _radius, Color bgcolor, bool cusp = false, RectangleAlign rectAlign = RectangleAlign.RightTop)
{
    ////抗鋸齒 等模式在Graphics外層自定義設(shè)置
    //g.SmoothingMode = SmoothingMode.AntiAlias;
    //漸變填充
    var  brush = new SolidBrush(bgcolor);
    g.DrawRoundRectAndCusp(rectangle, _radius, brush, cusp, rectAlign);
}

/// <summary>
/// 繪制Brush畫(huà)刷的圓角矩形，并指定是否有三角小尖及其位置
/// </summary>
/// <param name="g"></param>
/// <param name="rectangle">矩形區(qū)域</param>
/// <param name="_radius">圓角半徑</param>
/// <param name="bgbrush">指定背景畫(huà)刷</param>
/// <param name="cusp">是否有三角小尖，默認(rèn)無(wú)</param>
/// <param name="rectAlign">三角小尖的位置，默認(rèn)右上</param>
public static void DrawRoundRectAndCusp(this Graphics g, Rectangle rectangle, int _radius, Brush bgbrush, bool cusp = false, RectangleAlign rectAlign = RectangleAlign.RightTop)
{
    ////抗鋸齒 盡可能高質(zhì)量繪制
    g.TextRenderingHint = System.Drawing.Text.TextRenderingHint.AntiAlias;
    g.PixelOffsetMode = PixelOffsetMode.HighQuality;
    g.SmoothingMode = SmoothingMode.AntiAlias; // SmoothingMode.HighQuality 
    g.CompositingQuality = CompositingQuality.HighQuality;
    g.InterpolationMode = InterpolationMode.HighQualityBilinear;

    var rect = rectangle;
    //畫(huà)尖角 對(duì)應(yīng)的變更rect區(qū)域
    if (cusp)
    {
        // 尖角的大小 默認(rèn)為 開(kāi)始位置為_(kāi)radius 底邊為20，高度為13的等腰三角形
        var cuspHemlineStart = _radius;
        var cuspHemlineLength = 20;
        var cuspHeight = 13;

        // 讓位出來(lái)的間隔暫時(shí)為尖角高度-1
        var span = cuspHeight - 1;

        // 三角頂點(diǎn)
        PointF p1, p2, p3;

        switch (rectAlign)
        {
            case RectangleAlign.AboveLeft:
                p1 = new PointF(rectangle.X + cuspHemlineStart, rectangle.Y + cuspHeight);
                p2 = new PointF(rectangle.X + cuspHemlineStart + cuspHemlineLength, rectangle.Y + cuspHeight);
                p3 = new PointF(rectangle.X + cuspHemlineStart + cuspHemlineLength / 2, rectangle.Y);
                rect = new Rectangle(rectangle.X, rectangle.Y + span, rectangle.Width, rectangle.Height - span);
                break;
            case RectangleAlign.AboveRight:
                p1 = new PointF(rectangle.Right - cuspHemlineStart, rectangle.Y + cuspHeight);
                p2 = new PointF(rectangle.Right - cuspHemlineStart - cuspHemlineLength, rectangle.Y + cuspHeight);
                p3 = new PointF(rectangle.Right - cuspHemlineStart - cuspHemlineLength / 2, rectangle.Y);
                rect = new Rectangle(rectangle.X, rectangle.Y + span, rectangle.Width, rectangle.Height - span);
                break;
            case RectangleAlign.RightBottom:
                p1 = new PointF(rectangle.Right - cuspHeight, rectangle.Bottom - cuspHemlineStart);
                p2 = new PointF(rectangle.Right - cuspHeight, rectangle.Bottom - cuspHemlineStart - cuspHemlineLength);
                p3 = new PointF(rectangle.Right, rectangle.Bottom - cuspHemlineStart - cuspHemlineLength / 2);
                rect = new Rectangle(rectangle.X, rectangle.Y, rectangle.Width - span, rectangle.Height);
                break;
            case RectangleAlign.BelowRight:
                p1 = new PointF(rectangle.Right - cuspHemlineStart, rectangle.Bottom - cuspHeight);
                p2 = new PointF(rectangle.Right - cuspHemlineStart - cuspHemlineLength, rectangle.Bottom - cuspHeight);
                p3 = new PointF(rectangle.Right - cuspHemlineStart - cuspHemlineLength / 2, rectangle.Bottom);
                rect = new Rectangle(rectangle.X, rectangle.Y, rectangle.Width, rectangle.Height - span);
                break;
            case RectangleAlign.BelowLeft:
                p1 = new PointF(rectangle.X + cuspHemlineStart, rectangle.Bottom - cuspHeight);
                p2 = new PointF(rectangle.X + cuspHemlineStart + cuspHemlineLength, rectangle.Bottom - cuspHeight);
                p3 = new PointF(rectangle.X + cuspHemlineStart + cuspHemlineLength / 2, rectangle.Bottom);
                rect = new Rectangle(rectangle.X, rectangle.Y, rectangle.Width, rectangle.Height - span);
                break;
            case RectangleAlign.LeftBottom:
                p1 = new PointF(rectangle.X + cuspHeight, rectangle.Bottom - cuspHemlineStart);
                p2 = new PointF(rectangle.X + cuspHeight, rectangle.Bottom - cuspHemlineStart - cuspHemlineLength);
                p3 = new PointF(rectangle.X, rectangle.Bottom - cuspHemlineStart - cuspHemlineLength / 2);
                rect = new Rectangle(rectangle.X + span, rectangle.Y, rectangle.Width - span, rectangle.Height);
                break;
            case RectangleAlign.LeftTop:
                p1 = new PointF(rectangle.X + cuspHeight, rectangle.Y + cuspHemlineStart);
                p2 = new PointF(rectangle.X + cuspHeight, rectangle.Y + cuspHemlineStart + cuspHemlineLength);
                p3 = new PointF(rectangle.X, rectangle.Y + cuspHemlineStart + cuspHemlineLength / 2);
                rect = new Rectangle(rectangle.X + span, rectangle.Y, rectangle.Width - span, rectangle.Height);
                break;
            case RectangleAlign.RightTop:
            default:
                p1 = new PointF(rectangle.Right - cuspHeight, rectangle.Y + cuspHemlineStart);
                p2 = new PointF(rectangle.Right - cuspHeight, rectangle.Y + cuspHemlineStart + cuspHemlineLength);
                p3 = new PointF(rectangle.Right, rectangle.Y + cuspHemlineStart + cuspHemlineLength / 2);
                rect = new Rectangle(rectangle.X, rectangle.Y, rectangle.Width - span, rectangle.Height);
                break;
        }

        PointF[] ptsArray = new PointF[] { p1, p2, p3 };

        // 填充參數(shù)點(diǎn)所指定的多邊形內(nèi)部
        g.FillPolygon(bgbrush, ptsArray);
    }
    //填充
    g.FillPath(bgbrush, rect.GetRoundedRectPath(_radius));
}

/// <summary> 
/// 根據(jù)普通矩形得到圓角矩形的路徑 【根據(jù)矩形區(qū)域rect，計(jì)算呈現(xiàn)radius圓角的Graphics路徑】
/// </summary> 
/// <param name="rect">原始矩形</param> 
/// <param name="radius">半徑</param> 
/// <returns>圖形路徑</returns> 
public static GraphicsPath GetRoundedRectPath(this Rectangle rect, int radius)
{
    #region 正確繪制圓角矩形區(qū)域
    int R = radius*2;
    Rectangle arcRect = new Rectangle(rect.Location, new Size(R, R));
    GraphicsPath path = new GraphicsPath();

    if (radius <= 0)
    {
        path.AddRectangle(rect);
    }
    else
    {
        // 左上圓弧 左手坐標(biāo)系，順時(shí)針為正 從180開(kāi)始，轉(zhuǎn)90度
        path.AddArc(arcRect, 180, 90);
        // 右上圓弧
        arcRect.X = rect.Right - R;
        path.AddArc(arcRect, 270, 90);
        // 右下圓弧
        arcRect.Y = rect.Bottom - R;
        path.AddArc(arcRect, 0, 90);
        // 左下圓弧
        arcRect.X = rect.Left;
        path.AddArc(arcRect, 90, 90);
    }

    //path.CloseFigure();
    // 閉合路徑中所有開(kāi)放圖形，并形成新圖形
    path.CloseAllFigures();
    return path;
    #endregion
}

/// <summary> 
/// 獲取圓角矩形的路徑 
/// </summary> 
/// <param name="rect">原始矩形</param> 
/// <param name="radius">半徑</param> 
/// <returns>圖形路徑</returns> 
public static GraphicsPath GetRoundedRectPath(int x, int y, int width, int height, int radius)
{
    Rectangle rect = new Rectangle(x, y, width, height);
    return rect.GetRoundedRectPath(radius);
}

測(cè)試尖角的顯示位置

復(fù)制幾個(gè)Panel，在Paint事件中分別處理尖角的位置

panel1.Paint += Panel1_Paint;
panel3.Paint += Panel1_Paint;
panel4.Paint += Panel1_Paint;
panel5.Paint += Panel1_Paint;
panel6.Paint += Panel1_Paint;
panel7.Paint += Panel1_Paint;
panel8.Paint += Panel1_Paint;
panel9.Paint += Panel1_Paint;
/// ......
private void Panel1_Paint(object sender, PaintEventArgs e)
{
    var panel = sender as Panel;
    var rectAlign = RectangleAlign.RightTop;
    switch (panel.Name)
    {
        case "panel3":
            rectAlign = RectangleAlign.AboveLeft;
            break;
        case "panel4":
            rectAlign = RectangleAlign.AboveRight;
            break;
        case "panel5":
            rectAlign = RectangleAlign.BelowLeft;
            break;
        case "panel6":
            rectAlign = RectangleAlign.BelowRight;
            break;
        case "panel7":
            rectAlign = RectangleAlign.LeftBottom;
            break;
        case "panel8":
            rectAlign = RectangleAlign.LeftTop;
            break;
        case "panel9":
            rectAlign = RectangleAlign.RightBottom;
            break;
        default:
            break;
    }

    var rect=e.Graphics.DrawRoundRectAndCusp(new Rectangle(0, 0, panel.Width, panel.Height), 18, Color.FromArgb(90, 143, 0), Color.FromArgb(41, 67, 0),true, rectAlign);

    e.Graphics.DrawText(rect, "這是一個(gè)Panel控件，非常適合顯示消息", Color.White, panel.Font);
}

查看效果：

重繪控件后文本的處理

由于重新繪制導(dǎo)致文本也被覆蓋的情況，有比較常見(jiàn)的兩種處理方法：

重繪控件的同時(shí)，重繪文本文字
通過(guò)添加Label控件實(shí)現(xiàn)文本處理

同時(shí)重繪文本

同樣將繪制文本的方法提取為擴(kuò)展方法，借助StringFormat字符串格式對(duì)象實(shí)現(xiàn)文字的布局處理。

不推薦使用Graphics.DrawString繪制按鈕控件（Rectangle區(qū)域）內(nèi)的文字，當(dāng)然DrawString也有一定有時(shí)比如文字方向的處理。

/// <summary>
/// 繪制(控件區(qū)域)文本內(nèi)容
/// </summary>
/// <param name="g"></param>
/// <param name="rect"></param>
/// <param name="text"></param>
/// <param name="color"></param>
/// <param name="font"></param>
/// <param name="_textAlign">文字布局，默認(rèn)居中。實(shí)際測(cè)試并未真正的居中，垂直方向偏上，改為通過(guò)計(jì)算rect的中心位置實(shí)現(xiàn)，使用微軟雅黑還好點(diǎn)，字體大小最好偶數(shù)</param>
/// <param name="rtl">是否RightToLeft 無(wú)效果，不推薦使用</param>
public static void DrawText(this Graphics g, Rectangle rect, string text, Color color, Font font, ContentAlignment _textAlign = ContentAlignment.MiddleCenter, bool rtl=false)
{
        var formatFlags = TextFormatFlags.HorizontalCenter | TextFormatFlags.VerticalCenter; // 默認(rèn)居中
        switch (_textAlign)
        {
            case ContentAlignment.TopLeft:
                formatFlags = TextFormatFlags.Top | TextFormatFlags.Left;
                break;
            case ContentAlignment.TopCenter:
                formatFlags = TextFormatFlags.Top | TextFormatFlags.HorizontalCenter;
                break;
            case ContentAlignment.TopRight:
                formatFlags = TextFormatFlags.Top | TextFormatFlags.Right;
                break;
            case ContentAlignment.MiddleLeft:
                formatFlags = TextFormatFlags.VerticalCenter | TextFormatFlags.Left;
                break;
            case ContentAlignment.MiddleRight:
                formatFlags = TextFormatFlags.VerticalCenter | TextFormatFlags.Right;
                break;
            case ContentAlignment.BottomLeft:
                formatFlags = TextFormatFlags.Bottom | TextFormatFlags.Left;
                break;
            case ContentAlignment.BottomCenter:
                formatFlags = TextFormatFlags.Bottom | TextFormatFlags.HorizontalCenter;
                break;
            case ContentAlignment.BottomRight:
                formatFlags = TextFormatFlags.Bottom | TextFormatFlags.Right;
                break;
            case ContentAlignment.MiddleCenter:
            default:
                break;
        }
        if (rtl)
        {
            formatFlags |= TextFormatFlags.RightToLeft; // 無(wú)效果
        }
        TextRenderer.DrawText(g, text, font, rect, color, formatFlags);
}

要注意添加了小三角后的文字繪制區(qū)域問(wèn)題，如果使用默認(rèn)的全部預(yù)期有可能導(dǎo)致文字超出范圍，且，布局也不是相對(duì)于繪制的主體。如下圖對(duì)比的效果。

因此，可修改圓角繪制的函數(shù)，使其返回繪制后的主體區(qū)域。

private void Panel1_Paint(object sender, PaintEventArgs e)
{
    var panel = sender as Panel;
    var rect=e.Graphics.DrawRoundRectAndCusp(new Rectangle(0, 0, panel.Width, panel.Height), 18, Color.FromArgb(90, 143, 0), Color.FromArgb(41, 67, 0),true, rectAlign);

    //e.Graphics.DrawText(e.ClipRectangle, "這是一個(gè)Panel控件，非常適合顯示消息", Color.White, panel.Font);
    // 使用合適的區(qū)域
    e.Graphics.DrawText(rect, "這是一個(gè)Panel控件，非常適合顯示消息", Color.White, panel.Font);
}

通過(guò)添加Label控件實(shí)現(xiàn)對(duì)文本的處理【有尖角時(shí)需要額外處理】

label2.Text = "我是Label顯示在圓角按鈕上";
label2.Parent = button1;
label2.AutoSize = false;
label2.Dock = DockStyle.Fill;
label2.BackColor = Color.Transparent;
label2.TextAlign = ContentAlignment.MiddleCenter;
label2.ForeColor = Color.Wheat;

Paint事件中繪制圓角的優(yōu)點(diǎn)

完全由用戶繪制按鈕區(qū)域?qū)崿F(xiàn)圓角【之前文章介紹過(guò)】，可以發(fā)現(xiàn)，與直接在Paint事件中實(shí)現(xiàn)圓角，有著一定的鋸齒，雖然不是很嚴(yán)重，但是還是Paint事件中實(shí)現(xiàn)的圓角看著相對(duì)好一些。

之前完全由用戶繪制控件區(qū)域出現(xiàn)鋸齒的問(wèn)題，原因在于使用new Region(graphicPath)構(gòu)造函數(shù)創(chuàng)建的新Region對(duì)象，創(chuàng)建的Region無(wú)法實(shí)現(xiàn)抗鋸齒，即使開(kāi)始抗鋸齒和高質(zhì)量繪制（無(wú)法應(yīng)用到最終的Region）。

[唯一的]解決辦法，是不創(chuàng)建新的Region，直接繪制無(wú)鋸齒圖形【無(wú)法對(duì)Region進(jìn)行抗鋸齒】。

窗體失去焦點(diǎn)時(shí)按鈕外觀邊框問(wèn)題

窗體失去焦點(diǎn)后，Button會(huì)顯示出一個(gè)邊框（即使已經(jīng)設(shè)置BorderSize為0），只有在窗體失去焦點(diǎn)后，最后一個(gè)被激活過(guò)的Button（點(diǎn)擊過(guò)的）才會(huì)出現(xiàn)。

比較好的解決辦法是在Button的Paint事件中執(zhí)行Button.NotifyDefault(false)方法。

下面是幾種解決方式：

通過(guò)繼承Button控件，重寫(xiě)NotifyDefault方法實(shí)現(xiàn)。

class MyButton:Button
{
    public override void NotifyDefault(bool value)
    {
        base.NotifyDefault(false);
    }
}

設(shè)置FlatAppearance.BorderColor顏色與下層背景色一致

或者，還有一個(gè)取巧的解決辦法，就是，設(shè)置FlatAppearance.BorderColor為Button按鈕后面的背景色，這樣就看不出來(lái)，類似沒(méi)有的效果。如 button1.FlatAppearance.BorderColor = SystemColors.Control;。

在Button的Paint事件方法中調(diào)用NotifyDefault(false)

或者，不是繼承重寫(xiě)B(tài)utton控件，直接在Button的Paint事件中，調(diào)用Button.NotifyDefault(false);方法。

private void Button1_Paint(object sender, PaintEventArgs e)
{
    var btn = (Button)sender;
    e.Graphics.DrawRoundRectAndCusp(new Rectangle(0, 0, btn.Width, btn.Height), 18, Color.FromArgb(0, 122, 204), Color.FromArgb(8, 39, 57));

    ((Button)sender).NotifyDefault(false); // 去除窗體失去焦點(diǎn)時(shí)最新激活的按鈕邊框外觀樣式
}

Paint事件中繪制控件的問(wèn)題【不要使用(事件)參數(shù)e.ClipRectangle】

直接看下圖演示，在發(fā)生控件大小、位置調(diào)整等需要重繪時(shí)，會(huì)發(fā)生控件錯(cuò)亂、顯示不完整重疊等問(wèn)題。

比如Panel事件中，原本的寫(xiě)法為：

var rect=e.Graphics.DrawRoundRectAndCusp(e.ClipRectangle, 18, Color.FromArgb(90, 143, 0), Color.FromArgb(41, 67, 0),true, rectAlign);

將其改為轉(zhuǎn)換傳遞過(guò)來(lái)的控件參數(shù)為Panel對(duì)象，并通過(guò)其寬高獲取其繪制區(qū)域：

var rect=e.Graphics.DrawRoundRectAndCusp(new Rectangle(0, 0, panel.Width, panel.Height), 18, Color.FromArgb(90, 143, 0), Color.FromArgb(41, 67, 0),true, rectAlign);

修改后錯(cuò)亂問(wèn)題就不存在了：

到此這篇關(guān)于Winform控件優(yōu)化Paint事件實(shí)現(xiàn)圓角組件及提取繪制圓角的擴(kuò)展方法的文章就介紹到這了,更多相關(guān)Winform控件優(yōu)化內(nèi)容請(qǐng)搜索腳本之家以前的文章或繼續(xù)瀏覽下面的相關(guān)文章希望大家以后多多支持腳本之家！

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