winform实现控件透明（实现真透明）

川长思鸟来 2023-01-13 15:58 377阅读 0赞

使用BackColor=Color.Translate这种方法只能实现和背景色一样但是不是真的透明，控件后面的控件还是看不到

1.首先写一个基类

using System;
    using System.Collections.Generic;
    using System.Text;
    using System.Windows.Forms;
    using System.Drawing;
    using System.ComponentModel;
     
    namespace CYControls
    {
        /// <summary>
        /// 提供透明和旋转功能的基础控件
        /// </summary>
        public class CYBaseControl : Control
        {
            private float _iBorderThickness = 1f;
            private float _iOpacity = 1f;
            private Brush _brushBg = null;
            private Pen _penFg = null;
     
            public CYBaseControl()
            {
                this.SetStyle(ControlStyles.SupportsTransparentBackColor |
                    ControlStyles.Opaque, true);
                this.BackColor = Color.Transparent;
                BackgroundBrush = Brushes.Transparent;
                ForegroundPen = Pens.Black;
            }
     
            #region Propertys
            #region HideParent
            [Browsable(false)]
            [EditorBrowsable(EditorBrowsableState.Never)]
            public override string Text
            {
                get { return base.Text; }
                set { base.Text = value; }
            }
     
            [Browsable(false)]
            [EditorBrowsable(EditorBrowsableState.Never)]
            public override Image BackgroundImage
            {
                get { return base.BackgroundImage; }
                set { base.BackgroundImage = value; }
            }
     
            [Browsable(false)]
            [EditorBrowsable(EditorBrowsableState.Never)]
            public override ImageLayout BackgroundImageLayout
            {
                get
                {
                    return base.BackgroundImageLayout;
                }
                set
                {
                    base.BackgroundImageLayout = value;
                }
            }
            #endregion
     
            public override Color BackColor
            {
                get
                {
                    return base.BackColor;
                }
                set
                {
                    base.BackColor = value;
                    ResetBgBrush();
                }
            }
     
            //[EditorAttribute(typeof(BrushTypeEditor), typeof(System.Drawing.Design.UITypeEditor))]  
            //public double Background
            //{
            //    get;
            //    set;
            //}
     
            public override Color ForeColor
            {
                get
                {
                    return base.ForeColor;
                }
                set
                {
                    base.ForeColor = value;
                    ResetFgPen();
                }
            }
     
            public float BorderThickness
            {
                get { return _iBorderThickness; }
                set
                {
                    if (value < 0)
                    {
                        throw new Exception("Out off range");
                    }
                    _iBorderThickness = value;
                    ResetFgPen();
                    ResetDrawRect();
                }
            }
     
            public virtual float RotateAngle
            {
                get;
                set;
            }
     
     
            public float Opacity
            {
                get { return _iOpacity; }
                set
                {
                    if (value > 1 || value < 0)
                    {
                        throw new Exception("Out of range,the Value be in [0,1]");
                    }
                    else
                    {
                        _iOpacity = value;
                        ResetBrushes();
                    }
                }
            }
     
            protected override CreateParams CreateParams
            {
                get
                {
                    CreateParams cp = base.CreateParams;
                    cp.ExStyle = 0x20;
                    return cp;
                }
            }
     
            protected virtual Brush BackgroundBrush
            {
                get { return _brushBg; }
                set { _brushBg = value; }
            }
     
            protected virtual Pen ForegroundPen
            {
                get { return _penFg; }
                set { _penFg = value; }
            }
     
            protected virtual RectangleF DrawRect
            {
                get;
                set;
            }
            #endregion
     
            #region Methods
            protected override void OnPaint(PaintEventArgs e)
            {
                base.OnPaint(e);
                e.Graphics.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;
            }
     
            protected override void OnSizeChanged(EventArgs e)
            {
                base.OnSizeChanged(e);
                ResetDrawRect();
            }
            protected override void OnPaddingChanged(EventArgs e)
            {
                base.OnPaddingChanged(e);
                ResetDrawRect();
            }
     
            protected void ResetBrushes()
            {
                ResetBgBrush();
                ResetFgPen();
            }
     
            protected void ResetBgBrush()
            {
                BackgroundBrush = new SolidBrush(GetOpacityColor(BackColor, Opacity));
            }
     
            protected void ResetFgPen()
            {
                ForegroundPen = new Pen(GetOpacityColor(ForeColor, Opacity), BorderThickness);
            }
     
            protected Color GetOpacityColor(Color baseColor, float op)
            {
                return Color.FromArgb(Convert.ToInt32(op * baseColor.A), baseColor);
            }
     
            private void ResetDrawRect()
            {
                float dbwidth = 2 * BorderThickness;
                float halfwidth = BorderThickness / 2;
                int paddingWhith = Padding.Left   Padding.Right;
                int paddingHeight = Padding.Top   Padding.Bottom;
                if (dbwidth > Width - paddingWhith || dbwidth > Height - paddingHeight)
                {
                    DrawRect = this.Bounds;
                }
                else
                {
                    DrawRect = new RectangleF(Padding.Left   halfwidth,
                        Padding.Top   halfwidth,
                        Width - BorderThickness - paddingWhith,
                        Height - BorderThickness - paddingHeight);
                }
            }
            #endregion
        }
    }

2.创建RectangleShape

public class RectangleShape:CYBaseControl
    {
        protected override void OnPaint(System.Windows.Forms.PaintEventArgs e)
        {
            base.OnPaint(e);
            e.Graphics.FillRectangle(BackgroundBrush,this.ClientRectangle);
            e.Graphics.DrawRectangle(ForegroundPen,Rectangle.Round(this.DrawRect));
        }
    }

3.应用实例

RectangleShape recS=new RectangleShape ();
    recS.Name="TestShape";
    recS.Height=100;
    recS.Width=100;
    recS.BackColor=Color.Transparent;
    recS.Location=new Point(0,0);
    //设置透明度
    recS.Opacity=0.5F;
    //把自定义的这个控件添加到需要的容器中
    **.Controls.Add(recS);