C#皮肤美化：制作类似QQ带光晕的文本框Textbox

本篇C#皮肤美化实例将制作一个类似QQ的带光晕的文本框Textbox，还是先看看最终的效果图(和QQ登陆中的输入框效果差不多)：

效果说明： 1.实现了水印的效果 2.实现了鼠标移上去的时候周围产生辉光 3.输入前端可以设置图片。

实现辉光效果

    整体说明：

          前面显示的那个图片我采用的是一个picturebox，当然如果你愿意也可以自己画（后续的“button再探讨”中就采用的是自己画的方式）。图片后面的输入文本框采用的是textbox控件，这样一来就避免了许多绘制textbox的麻烦（我一开始打算自己绘制用户输入的字符的，不过发现不理想）。然后边框和辉光都是画出来的。

  具体实现：

 先抛开水印不说。最重要的就是重写的OnPaint方法，如下：

protected override void OnPaint(PaintEventArgs e)
        {
            Graphics g = e.Graphics;
            g.InterpolationMode = InterpolationMode.HighQualityBicubic;
            g.SmoothingMode = SmoothingMode.HighQuality;

            CalculateSizeAndPosition();
            Draw(e.ClipRectangle, e.Graphics);

            base.OnPaint(e);
        }

可以看出里面调用了两个方法，做过前面窗体换肤的可能对这个不陌生。就是绘画之前计算好所有的位置大小信息，然后再调用draw画出来。那么这次的calculateSizeAndPosition又做了什么呢？2点！1.判断是否有前端图片需要显示，2.判断是否处于multiline模式。代码如下：

private void CalculateSizeAndPosition()
        {
            if (ForeImage != null)
            {
                //图片大小固定为16
                pic.Height = pic.Width = 16;
                pic.Top = pic.Left = 3;
                txt.Width = Width - pic.Width - 12;
                txt.Location = new Point(16 + 3 + 3, 6);
            }
            else
            {
                pic.Left = -40;  //隐藏图片
                  txt.Width = Width - 9;
                txt.Location = new Point(3, 6);
            }

            //单行
            if (!txt.Multiline)
            {
                Height = txt.Height + 9;
            }
            else
            {
                txt.Height = Height - 9;  //如果是多行则设置实际里面的输入文本框的高度
            }
        }

当所有的东西都计算好了，我们就可以安心的拿起我们的画笔竟然绘画了。先画什么？再画什么？请看代码：

private void Draw(Rectangle rectangle, Graphics g)
        {

            #region 画背景
            using (SolidBrush backgroundBrush = new SolidBrush(Color.White))
            {
                g.FillRectangle(backgroundBrush, 2, 2, this.Width - 5, this.Height -4);
            }
            #endregion

            #region 画阴影(外边框)

            Color drawShadowColor = _shadowColor;
            if (!_isFouse)    //判断是否获得焦点
            {
                drawShadowColor = Color.Transparent;
            }
            using (Pen shadowPen = new Pen(drawShadowColor))
            {
                if (_radius == 0)
                {
                    g.DrawRectangle(shadowPen, new Rectangle(rectangle.X, rectangle.Y, rectangle.Width - 1, rectangle.Height - 1));
                }
                else
                {
                    g.DrawPath(shadowPen, DrawHelper.DrawRoundRect(rectangle.X, rectangle.Y, rectangle.Width - 2, rectangle.Height - 1, _radius));
                }
            }
            #endregion

            #region 画边框
            using (Pen borderPen = new Pen(_borderColor))
            {
                if (_radius == 0)
                {
                    g.DrawRectangle(borderPen, new Rectangle(rectangle.X + 1, rectangle.Y + 1, rectangle.Width - 3, rectangle.Height - 3));
                }
                else
                {
                    g.DrawPath(borderPen, DrawHelper.DrawRoundRect(rectangle.X + 1, rectangle.Y + 1, rectangle.Width - 3, rectangle.Height - 2, _radius));
                }
            }
            #endregion
        }

在这个方法里面主要画了三个东西，大家看注释也知道了，分别是：背景，边框，辉光。要注意的就是这里面的微小距离要设置好，我也改了好几次才设置正确。在画边框和辉光的时候，因为实现了圆角边框所以要对圆角度进行判断。

现在绘画的方法也做好了，接下来就是出发重绘的事件了。不然它也不会自动帮你绘画啊^_^。显然当鼠标移上去和移出去的时候需要重新绘画。那我们就在下面几个方法中引发重绘事件：

 private void TextBoxEx2_MouseEnter(object sender, EventArgs e)
        {
            _isFouse = true;
            this.Invalidate();
        }

        private void TextBoxEx2_MouseLeave(object sender, EventArgs e)
        {
            _isFouse = false;
            this.Invalidate();
        }

代码很简单，不解释。

基本上面的做好了，大部分就完成了。下面我们完成水印的功能。至此，textbox美化讲解完毕，希望对你有帮助

实现水印效果

      水印我是这样子实现的：当用户离开输入焦点的时候检测当前用户有没有输入字符，如果没有输入则改变输入框的颜色（灰色），然后看起来就像是水印的感觉啦。我们专门写了一个函数来设置水印，如下：

private void SetWaterMark()
        {
            if (_waterMark != null && (txt.Text == " " || txt.Text == @" " + WaterMark))  //用户没有输入
            {    
                txt.ForeColor = _waterMarkColor;
                txt.Text = @" " + WaterMark;
            }
            else
            {
                txt.ForeColor = ForeColor;
            }
        }

然后在什么地方调用呢？刚才上面也已经说了当用户离开焦点的时候判断，不过用户获得输入焦点的时候我们还要设置一下，如果当前的文本时水印的话就清空文本等待输入：

private void Txt_GotFocus(object sender, EventArgs e)
        {
            if (txt.Text == @" " + WaterMark)
            {
                //获得焦点，切换正常文字等待填写
                txt.ForeColor = ForeColor;
                txt.Text = " ";
            }
        }

        private void Txt_LostFocus(object sender, EventArgs e)
        {
            SetWaterMark();
        }

这里还有一点需要注意的是，在pageload里面我们也需要调用一下setwatermark方法，不然它一开始是不会显示滴！

源代码快照

namespace QLFUI
{
    public partial class TextBoxEx : UserControl
    {
        #region - 变量 -

        private Color _borderColor = Color.FromArgb(166, 208, 226);
        private Color _shadowColor = Color.FromArgb(175, 212, 228);
        private Image _foreImage = null;
        private bool _isFouse = false;
        private Color _backColor = Color.Transparent;
        private string _waterMark = null;
        private Color _waterMarkColor = Color.Silver;
        private Color _foreColor = Color.Black;
        private int _radius = 3;

        #endregion

        #region - 属性 -

        [Category("QLFUI"), Description("边框颜色,BorderStyle为FixedSingle有效")]
        public Color BorderColor
        {
            get { return _borderColor; }
            set
            {
                _borderColor = value;
                this.Invalidate();
            }
        }

        [Category("QLFUI"), Description("边框阴影颜色,BorderStyle为FixedSingle有效")]
        public Color ShadowColor
        {
            get { return _shadowColor; }
            set
            {
                _shadowColor = value;
                this.Invalidate();
            }
        }

        [Category("QLFUI"), Description("显示的前端的图片")]
        public Image ForeImage
        {
            get { return pic.Image; }
            set
            {
                _foreImage = value;
                pic.Image = _foreImage;
                Invalidate();
            }
        }

        [Category("QLFUI"), Description("文字")]
        public string Caption
        {
            get
            {
                return txt.Text;
            }
            set
            {
                txt.Text = value;
                SetWaterMark();
                Invalidate();
            } 
        }

        [Category("行为"), Description("是否多行显示")]
        public bool Multiline
        {
            get { return txt.Multiline; }
            set
            {
                txt.Multiline = value;
            }
        }

        [Category("行为"), Description("是否以密码形式显示字符")]
        public bool UseSystemPasswordChar
        {
            get { return txt.UseSystemPasswordChar; }
            set
            {
                txt.UseSystemPasswordChar = value;
            }
        }

        [Category("QLFUI"), Description("水印文字")]
        public string WaterMark
        {
            get { return _waterMark; }
            set
            {
                _waterMark = value;
                Invalidate();
            }
        }

        [Category("QLFUI"), Description("水印颜色")]
        public Color WaterMarkColor
        {
            get { return _waterMarkColor; }
            set
            {
                _waterMarkColor = value;
                Invalidate();
            }
        }

        #region 需要被隐藏的属性

        [Browsable(false)]
        public new BorderStyle BorderStyle
        {
            get { return BorderStyle.None; }
        }

        [Browsable(false)]
        public new Color BackColor
        {
            get { return base.BackColor; }
            set { base.BackColor = value; }
        }

        [Browsable(false)]
        public new Image BackgroundImage
        {
            get { return null; }
        }

        [Browsable(false)]
        public new ImageLayout BackgroundImageLayout
        {
            get { return base.BackgroundImageLayout; }
            set { base.BackgroundImageLayout = value; }
        }

        #endregion

        [Category("QLFUI"), Description("边角弯曲的角度(1-10),数值越大越弯曲")]
        public int Radius
        {
            get { return _radius; }
            set
            {
                if (value > 10)
                {
                    value = 10;
                }
                if (value < 0)
                {
                    value = 0;
                }
                _radius = value;
                this.Invalidate();
            }
        }

        [Browsable(true)]
        [Category("外观"), Description("文本颜色")]
        public new Color ForeColor
        {
            get { return _foreColor; }
            set { _foreColor = value; }
        }

        [Browsable(true)]
        [Category("外观"), Description("鼠标形状")]
        public new Cursor Cursor
        {
            get { return txt.Cursor; }
            set { txt.Cursor = value; }
        }

        [Category("行为"), Description("自动提示方式")]
        public AutoCompleteMode AutoCompleteMode
        {
            get { return txt.AutoCompleteMode; }
            set { txt.AutoCompleteMode = value; }
        }

        [Category("行为"), Description("自动提示类型")]
        public AutoCompleteSource AutoCompleteSource
        {
            get { return txt.AutoCompleteSource; }
            set { txt.AutoCompleteSource = value; }
        }

        #endregion

        #region - 构造函数 -

        public TextBoxEx()
        {
            SetStyle(ControlStyles.OptimizedDoubleBuffer | ControlStyles.AllPaintingInWmPaint, true);
            InitializeComponent();

            BackColor = Color.Transparent;

            //下面的图片和文本框的大小位置必须设置，否则首次启动时
            //会出现莫名其妙的断痕
            pic.SizeMode = PictureBoxSizeMode.StretchImage;
            pic.BorderStyle = BorderStyle.None;
            pic.Height = pic.Width = 16;//图片大小固定为16
            pic.Left = -40;  //隐藏图片
            txt.Width = Width - 9;
            txt.Location = new Point(3, 6);

            txt.MouseEnter += new EventHandler(TextBoxEx2_MouseEnter);
            txt.MouseLeave += new EventHandler(TextBoxEx2_MouseLeave);
            pic.MouseEnter += new EventHandler(TextBoxEx2_MouseEnter);
            pic.MouseLeave += new EventHandler(TextBoxEx2_MouseLeave);
            txt.LostFocus += new EventHandler(Txt_LostFocus);
            txt.GotFocus += new EventHandler(Txt_GotFocus);
            pic.BackColor = Color.White;  //不设置成白色则边框会一同加阴影
        }

        #endregion

        #region - 事件 -

        private void TextBoxEx_Load(object sender, EventArgs e)
        {
            SetWaterMark();
        }

        private void TextBoxEx2_MouseEnter(object sender, EventArgs e)
        {
            _isFouse = true;
            this.Invalidate();
        }

        private void TextBoxEx2_MouseLeave(object sender, EventArgs e)
        {
            _isFouse = false;
            this.Invalidate();
        }

        private void Txt_GotFocus(object sender, EventArgs e)
        {
            if (txt.Text == @" " + WaterMark)
            {
                //获得焦点，切换正常文字等待填写
                txt.ForeColor = ForeColor;
                txt.Text = " ";
            }
        }

        private void Txt_LostFocus(object sender, EventArgs e)
        {
            SetWaterMark();
        }

        protected override void OnPaint(PaintEventArgs e)
        {
            Graphics g = e.Graphics;
            g.InterpolationMode = InterpolationMode.HighQualityBicubic;
            g.SmoothingMode = SmoothingMode.HighQuality;

            CalculateSizeAndPosition();
            Draw(e.ClipRectangle, e.Graphics);
           

            base.OnPaint(e);
        }

        #endregion

        #region - 帮助方法 -

        private void SetWaterMark()
        {
            if (_waterMark != null && (txt.Text == " " || txt.Text == @" " + WaterMark))  //用户没有输入
            {    
                txt.ForeColor = _waterMarkColor;
                txt.Text = @" " + WaterMark;
            }
            else
            {
                txt.ForeColor = ForeColor;
            }
        }

        private void CalculateSizeAndPosition()
        {
            if (ForeImage != null)
            {
                pic.Top = pic.Left = 3;
                txt.Width = Width - pic.Width - 12;
                txt.Location = new Point(16 + 3 + 3, 6);
            }
            else
            {
                pic.Left = -40;  //隐藏图片
                txt.Width = Width - 9;
                txt.Location = new Point(3, 6);
            }

            //单行
            if (!txt.Multiline)
            {
                Height = txt.Height + 9;
            }
            else
            {
                txt.Height = Height - 9;
            }
        }

        private void Draw(Rectangle rectangle, Graphics g)
        {

            #region 画背景
            using (SolidBrush backgroundBrush = new SolidBrush(Color.White))
            {
                g.FillRectangle(backgroundBrush, 2, 2, this.Width - 5, this.Height -4);
            }
            #endregion

            #region 画阴影(外边框)

            Color drawShadowColor = _shadowColor;
            if (!_isFouse)    //判断是否获得焦点
            {
                drawShadowColor = Color.Transparent;
            }
            using (Pen shadowPen = new Pen(drawShadowColor))
            {
                if (_radius == 0)
                {
                    g.DrawRectangle(shadowPen, new Rectangle(rectangle.X, rectangle.Y, rectangle.Width - 1, rectangle.Height - 1));
                }
                else
                {
                    g.DrawPath(shadowPen, DrawHelper.DrawRoundRect(rectangle.X, rectangle.Y, rectangle.Width - 2, rectangle.Height - 1, _radius));
                }
            }
            #endregion

            #region 画边框
            using (Pen borderPen = new Pen(_borderColor))
            {
                if (_radius == 0)
                {
                    g.DrawRectangle(borderPen, new Rectangle(rectangle.X + 1, rectangle.Y + 1, rectangle.Width - 3, rectangle.Height - 3));
                }
                else
                {
                    g.DrawPath(borderPen, DrawHelper.DrawRoundRect(rectangle.X + 1, rectangle.Y + 1, rectangle.Width - 3, rectangle.Height - 2, _radius));
                }
            }
            #endregion
        }

        #endregion
    }
}