VB.NET中如何为DataGridView行标题添加不同颜色的透明图标

要实现每行标题的透明PNG图标颜色不同，核心是给原始图标动态生成对应颜色的版本，再在行标题绘制时加载使用。下面提供两种可行方案：

方案一：动态着色PNG图标（推荐） #

通过颜色矩阵给原始透明PNG图标着色，完整保留Alpha通道，适合各种类型的透明图标。

1. 图标着色工具函数 #

Private Function ColorizeIcon(originalIcon As Bitmap, targetColor As Color) As Bitmap
    Dim coloredBitmap As New Bitmap(originalIcon.Width, originalIcon.Height)
    Using g As Graphics = Graphics.FromImage(coloredBitmap)
        ' 构建颜色矩阵，对RGB通道应用目标颜色比例，保留透明度
        Dim colorMatrix As New ColorMatrix(New Single()() {
            New Single() {targetColor.R / 255.0F, 0, 0, 0, 0},
            New Single() {0, targetColor.G / 255.0F, 0, 0, 0},
            New Single() {0, 0, targetColor.B / 255.0F, 0, 0},
            New Single() {0, 0, 0, 1, 0},
            New Single() {0, 0, 0, 0, 1}
        })
        Using imageAttr As New ImageAttributes()
            imageAttr.SetColorMatrix(colorMatrix)
            g.DrawImage(originalIcon, New Rectangle(0, 0, originalIcon.Width, originalIcon.Height),
                        0, 0, originalIcon.Width, originalIcon.Height, GraphicsUnit.Pixel, imageAttr)
        End Using
    End Using
    Return coloredBitmap
End Function

2. 行标题绘制事件处理 #

在RowPostPaint事件中，根据行索引或绑定数据确定颜色，生成对应图标并绘制：

Private Sub DataGridView1_RowPostPaint(sender As Object, e As DataGridViewRowPostPaintEventArgs) Handles DataGridView1.RowPostPaint
    ' 加载原始透明图标（替换为你的资源路径/资源文件）
    Dim originalIcon As New Bitmap(My.Resources.YourOriginalIcon)
    Dim rowIndex As Integer = e.RowIndex
    
    ' 自定义每行颜色逻辑：示例用循环颜色，可替换为绑定数据的颜色值
    Dim rowColors As Color() = {Color.Red, Color.Green, Color.Blue, Color.Orange, Color.Purple}
    Dim targetColor As Color = rowColors(rowIndex Mod rowColors.Length)
    
    ' 生成对应颜色的图标
    Dim coloredIcon As Bitmap = ColorizeIcon(originalIcon, targetColor)
    
    ' 计算居中绘制的位置
    Dim headerRect As Rectangle = DataGridView1.RowHeadersRectangle(e.RowIndex)
    Dim drawX As Integer = headerRect.X + (headerRect.Width - coloredIcon.Width) \ 2
    Dim drawY As Integer = headerRect.Y + (headerRect.Height - coloredIcon.Height) \ 2
    
    ' 绘制着色后的图标
    e.Graphics.DrawImage(coloredIcon, drawX, drawY)
    
    ' 释放资源，避免内存泄漏
    coloredIcon.Dispose()
End Sub

方案二：绘制叠加色（适合轮廓类透明图标） #

如果你的图标是仅含黑色轮廓的透明图，可以直接绘制原始图标后，用目标颜色叠加填充非透明区域：

Private Sub DataGridView1_RowPostPaint(sender As Object, e As DataGridViewRowPostPaintEventArgs) Handles DataGridView1.RowPostPaint
    Dim originalIcon As New Bitmap(My.Resources.YourOutlineIcon)
    Dim rowIndex As Integer = e.RowIndex
    Dim rowColors As Color() = {Color.Red, Color.Green, Color.Blue, Color.Orange}
    Dim targetColor As Color = rowColors(rowIndex Mod rowColors.Length)
    
    Dim headerRect As Rectangle = DataGridView1.RowHeadersRectangle(e.RowIndex)
    Dim drawX As Integer = headerRect.X + (headerRect.Width - originalIcon.Width) \ 2
    Dim drawY As Integer = headerRect.Y + (headerRect.Height - originalIcon.Height) \ 2
    
    ' 先绘制原始图标，再用颜色叠加填充轮廓
    Using brush As New SolidBrush(targetColor)
        e.Graphics.DrawImage(originalIcon, drawX, drawY)
        ' 设置混合模式，仅填充图标非透明区域
        e.Graphics.CompositingMode = Drawing2D.CompositingMode.SourceAtop
        e.Graphics.FillRectangle(brush, drawX, drawY, originalIcon.Width, originalIcon.Height)
        ' 恢复默认混合模式
        e.Graphics.CompositingMode = Drawing2D.CompositingMode.SourceOver
    End Using
End Sub

额外说明 #

1. 行标题背景色自定义：如果需要给行标题本身设置不同颜色，可在绘制图标前先填充背景：

   e.Graphics.FillRectangle(New SolidBrush(Color.LightBlue), headerRect)
   

   或直接设置单元格样式：DataGridView1.Rows(rowIndex).HeaderCell.Style.BackColor = targetColor

2. 性能优化：如果行数较多，建议缓存已着色的图标（比如用Dictionary存储颜色对应的图标），避免每次绘制都重新生成。

内容的提问来源于stack exchange，提问作者roy