Question

c#怎么设置richtextbox透明

Answer 1

using System;  
using System.Collections.Generic;  
using System.ComponentModel;  
using System.Drawing;  
using System.Data;  
using System.Text;  
using System.Windows.Forms;

namespace LL
{
    public class UserRichTextBox : UserControl
    {
        public UserRichTextBox()
        {
            //为用户控制启用双缓冲等控件样式，否则RichTextBox输入时，会有残影  
            this.SetStyle(ControlStyles.AllPaintingInWmPaint |
                ControlStyles.UserPaint |
                ControlStyles.OptimizedDoubleBuffer, true);

            InitializeComponent();
        }

        /// <summary>   
        /// Required designer variable.  
        /// </summary>  
        private System.ComponentModel.IContainer components = null;

        /// <summary>   
        /// Clean up any resources being used.  
        /// </summary>  
        /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>  
        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
            {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        #region Component Designer generated code

        /// <summary>   
        /// Required method for Designer support - do not modify   
        /// the contents of this method with the code editor.  
        /// </summary>  
        private void InitializeComponent()
        {
            this.alphaRichTextBox1 = new LL.AlphaRichTextBox();
            this.SuspendLayout();
            //   
            // alphaRichTextBox1  
            //   
            this.alphaRichTextBox1.Dock = System.Windows.Forms.DockStyle.Fill;
            this.alphaRichTextBox1.Location = new System.Drawing.Point(0, 0);
            this.alphaRichTextBox1.Name = "alphaRichTextBox1";
            this.alphaRichTextBox1.Size = new System.Drawing.Size(150, 150);
            this.alphaRichTextBox1.TabIndex = 0;
            this.alphaRichTextBox1.Text = "";
            //   
            // UserRichTextBox  
            //   
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 12F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.Controls.Add(this.alphaRichTextBox1);
            this.Name = "UserRichTextBox";
            
            this.ResumeLayout(false);
        }

        #endregion

        public AlphaRichTextBox alphaRichTextBox1;

        protected override void OnLoad(EventArgs e)
        {
            base.OnLoad(e);

            //为测试效果，特加载背景图片  
            //this.BackgroundImageLayout = ImageLayout.None;
            //this.BackgroundImage = Image.FromFile(@"E:\Visual Studio 2010\Projects\LL\LL\Resources\title.png");
        }
    }

    public class AlphaRichTextBox : RichTextBox
    {
        //关键点：支持透明背景  
        protected override CreateParams CreateParams
        {
            get
            {
                CreateParams cp = base.CreateParams;
                cp.ExStyle |= 0x20;
                return cp;
            }
        }
    }
}

richtextbox是不能设置透明的，我这有个重写过的透明richtextbox，供你参考

Answer 2

要实现真正的透明效果还得用WPF，WINform只能通过图片背景颜色等替代方法间接实现。