DataGridView添加背景图后，无法显示单元格边框与值的问题求助

方案一：自定义绘制背景与单元格边框 #

直接通过DGV的绘图事件实现，无需额外控件，逻辑更直接：

1. 基础样式配置
   先设置DGV及单元格的透明属性，避免默认背景覆盖自定义背景：

Private bgImage As Drawing.Image

Public Sub New()
    InitializeComponent()
    bgImage = Drawing.Image.FromFile("C:\Images\VPBSSquare.Jpg")
    ' 调整背景图尺寸匹配DGV
    bgImage = New Bitmap(bgImage, DataGridView3.Size)
    
    ' 核心透明设置
    DataGridView3.DefaultCellStyle.BackColor = Color.Transparent
    DataGridView3.DefaultCellStyle.SelectionBackColor = Color.Transparent
    DataGridView3.BackgroundColor = Color.Transparent
    ' 关闭表头默认样式，避免遮挡背景
    DataGridView3.EnableHeadersVisualStyles = False
    DataGridView3.ColumnHeadersDefaultCellStyle.BackColor = Color.Transparent
    DataGridView3.RowHeadersDefaultCellStyle.BackColor = Color.Transparent
    ' 开启双缓冲消除闪烁
    DataGridView3.DoubleBuffered = True
End Sub

2. 绘制整体背景图
   在DGV的Paint事件中绘制覆盖整个控件的背景图：

Private Sub DataGridView3_Paint(sender As Object, e As PaintEventArgs) Handles DataGridView3.Paint
    e.Graphics.DrawImage(bgImage, 0, 0, DataGridView3.Width, DataGridView3.Height)
End Sub

3. 绘制单元格边框与内容
   在CellPainting事件中手动绘制完整边框，再渲染单元格内容：

Private Sub DataGridView3_CellPainting(sender As Object, e As DataGridViewCellPaintingEventArgs) Handles DataGridView3.CellPainting
    ' 跳过表头行/列
    If e.RowIndex < 0 Or e.ColumnIndex < 0 Then Return
    
    ' 填充透明背景
    e.Graphics.FillRectangle(Brushes.Transparent, e.CellBounds)
    
    ' 绘制完整单元格边框（黑色实线，可自定义颜色粗细）
    Using pen As New Pen(Color.Black, 1)
        e.Graphics.DrawLine(pen, e.CellBounds.Left, e.CellBounds.Top, e.CellBounds.Right, e.CellBounds.Top)
        e.Graphics.DrawLine(pen, e.CellBounds.Left, e.CellBounds.Bottom - 1, e.CellBounds.Right, e.CellBounds.Bottom - 1)
        e.Graphics.DrawLine(pen, e.CellBounds.Left, e.CellBounds.Top, e.CellBounds.Left, e.CellBounds.Bottom)
        e.Graphics.DrawLine(pen, e.CellBounds.Right - 1, e.CellBounds.Top, e.CellBounds.Right - 1, e.CellBounds.Bottom)
    End Using
    
    ' 绘制单元格内容（文本、值）
    e.PaintContent(e.CellBounds)
    
    ' 标记事件已处理，阻止默认绘制覆盖
    e.Handled = True
End Sub

方案二：使用PictureBox作为背景层 #

通过控件层级调整实现背景显示，需注意透明属性的正确设置：

1. 布局与控件配置

Private Sub FormLayout()
    Dim bgImageStr As String = "C:\Images\VPBSSquare.Jpg"
    
    ' 配置PictureBox作为背景层
    PictureBox1.Location = New Point(186, 41) ' 与DGV同位置
    PictureBox1.Size = New Size(228, 228)
    PictureBox1.Image = Image.FromFile(bgImageStr)
    PictureBox1.SizeMode = PictureBoxSizeMode.StretchImage
    Me.Controls.Add(PictureBox1)
    PictureBox1.SendToBack() ' 将背景层置于最底层
    
    ' 配置DGV透明与样式
    DataGridView1.Location = New Point(186, 41)
    DataGridView1.Size = New Size(228, 228)
    DataGridView1.DoubleBuffered = True
    DataGridView1.BackgroundColor = Color.Transparent
    DataGridView1.DefaultCellStyle.BackColor = Color.Transparent
    DataGridView1.DefaultCellStyle.SelectionBackColor = Color.Transparent
    DataGridView1.EnableHeadersVisualStyles = False
    DataGridView1.ColumnHeadersDefaultCellStyle.BackColor = Color.Transparent
    
    ' 设置单元格尺寸与内容样式
    For i As Integer = 0 To DataGridView1.Rows.Count - 1
        DataGridView1.Rows(i).Height = 76
    Next i
    For i As Integer = 0 To DataGridView1.Columns.Count - 1
        DataGridView1.Columns(i).Width = 76
        DataGridView1.Columns(i).DefaultCellStyle.Font = New Font("Microsoft Sans Serif", 30, FontStyle.Bold)
        DataGridView1.Columns(i).DefaultCellStyle.Alignment = DataGridViewContentAlignment.MiddleCenter
    Next i
End Sub

2. 关键注意事项

• 不要使用窗体TransparencyKey，会导致全局颜色透明，不符合需求；
• 必须同时设置DGV本身的BackgroundColor和单元格BackColor为透明，才能让底层PictureBox的背景透出；
• 开启DoubleBuffered可彻底解决绘制闪烁问题。

常见问题排查 #

• 边框不显示：检查CellPainting事件是否绘制了完整的四条边框（之前的代码只绘制了上下边框）；
• 背景图被覆盖：确认DGV及单元格的透明属性设置正确，且Paint事件绘制逻辑优先执行；
• 闪烁严重：确保开启DoubleBuffered，避免频繁触发重绘。

内容的提问来源于stack exchange，提问作者SsD