C#DataGridView绘制背景图片

缺乏、安全感 2022-09-10 10:27 229阅读 0赞

using System;
    using System.Collections.Generic;
    using System.ComponentModel;
    using System.Drawing;
    using System.Data;
    using System.Linq;
    using System.Text;
    using System.Windows.Forms;
    using System.Drawing.Drawing2D;
    
    namespace MyFormControlLibrary
    {
        public partial class MyDataGridView : DataGridView
        {
             private Image backImage;
    
            #region Property
            [Category("Custom"), Description("backgroundImage")]
            public Image BackImage
            {
                get { return backImage; }
                set { backImage = value; 
                    base .Refresh(); // 重新加载
                }
            }
            #endregion
    
            protected override void PaintBackground(Graphics graphics, Rectangle clipBounds, Rectangle gridBounds)
            {
                if (backImage != null)
                {
                    graphics.DrawImageUnscaledAndClipped(this.backImage, gridBounds);
                }
                else {
                    //如果不添加背景图片,会导致背景污染，应该需要调用上转型解决
                }
                
            }
    
            protected override void OnCellPainting(DataGridViewCellPaintingEventArgs e)
            {
                if (e.RowIndex == -1 || e.ColumnIndex == -1)
                {
                    Rectangle newRect = new Rectangle(e.CellBounds.X + 1,
                    e.CellBounds.Y + 1, e.CellBounds.Width - 4,
                    e.CellBounds.Height - 4);
    
                    using (
                        Brush gridBrush = new SolidBrush(this.GridColor),
                        backColorBrush = new SolidBrush(e.CellStyle.BackColor),
                        selectedColorBrush = new SolidBrush(e.CellStyle.SelectionBackColor))
                    {
                        using (Pen gridLinePen = new Pen(gridBrush))
                        {
                            e.Graphics.FillRectangle(backColorBrush, e.CellBounds);
                            if (e.Value != null)
                            {
                                e.Graphics.DrawString((String)e.Value, e.CellStyle.Font,
                                    Brushes.White, e.CellBounds.X + 2,
                                    e.CellBounds.Y + 2, StringFormat.GenericDefault);
                            }
                        }
                        Rectangle border = e.CellBounds;
                        border.Offset(new Point(-1, -1));
                        e.Graphics.DrawRectangle(Pens.Cyan, border);
                        e.Handled = true;
                    }
                }
                else
                {
                    Rectangle newRect = new Rectangle(e.CellBounds.X + 1,
                        e.CellBounds.Y + 1, e.CellBounds.Width - 4,
                        e.CellBounds.Height - 4);
    
                    using (
                        Brush gridBrush = new SolidBrush(this.GridColor),
                        backColorBrush = new SolidBrush(e.CellStyle.BackColor),
                        selectedColorBrush = new SolidBrush(e.CellStyle.SelectionBackColor))
                    {
                        using (Pen gridLinePen = new Pen(gridBrush))
                        {
                            if (this.Rows[e.RowIndex].Selected)
                            {
                                e.Graphics.FillRectangle(selectedColorBrush, e.CellBounds);
                            }
                            else
                            {
                                e.Graphics.FillRectangle(backColorBrush, e.CellBounds);
                            }
                            if (e.Value != null)
                            {
                                e.Graphics.DrawString((String)e.Value, e.CellStyle.Font,
                                    Brushes.White, e.CellBounds.X + 2,
                                    e.CellBounds.Y + 2, StringFormat.GenericDefault);
                            }
                        }
    
                        Rectangle border = e.CellBounds;
                        border.Offset(new Point(-1, -1));
                        e.Graphics.DrawRectangle(Pens.Cyan, border);
                        e.Handled = true;
                    }
    
                }
            }
        }
    }