Question

在运行时，我在Windows窗体中添加DataGridView。最后一列是DataGridViewImageColumn：

Dim InfoIconColumn As New DataGridViewImageColumn
MyDataGridView.Columns.Insert(MyDataGridView.Columns.Count, InfoIconColumn)

添加以下代码将使我的信息图标（位图）显示在每个列单元格中，但不显示在列标题中：

Dim InfoIcon As New Bitmap("C:\MyPath\InfoIcon.bmp")
InfoIconColumn.Image = InfoIcon

此外，值得注意的是，图像在细胞中显示“完美”，即它的大小正确以适合细胞。

但是，我找不到将相同图像添加到列标题单元格的方法。经过一些谷歌搜索后，我使用下面的代码将图像放在标题单元格中，但给我留下了两个问题：

图像没有像添加到列单元格时那样对列标题单元进行“自动调整大小”。图像略大且模糊不清。
使用_CellPainting事件减慢了效果，即当鼠标悬停在DataGridView上以突出显示所选行时，突出显示会落后于放置鼠标的位置。

以下是代码：

Private Sub MyDataGridView_CellPainting(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellPaintingEventArgs) Handles MyDataGridView.CellPainting
   Dim InfoIcon As Image = Image.FromFile("C:\MyPath\InfoIcon.bmp")
   If e.RowIndex = -1 AndAlso e.ColumnIndex = MyDataGridView.Columns.Count - 1 Then
       e.Paint(e.CellBounds, DataGridViewPaintParts.All And Not   DataGridViewPaintParts.ContentForeground)
       e.Graphics.DrawImage(InfoIcon, e.CellBounds)
       e.Handled = True
    End If
End Sub

有没有人知道解决我的问题的方法，并在运行时将一个尺寸合适的清晰图像放到DataGridViewImageColumn标题单元中？

Answer 1

你可以这样做的一种方法是使用CellsPainting事件来绘制特定标题单元格的位图。这是执行此操作的代码假设位图位于imagelist。

//this.images is an ImageList with your bitmaps
void dataGridView1_CellPainting(object sender, DataGridViewCellPaintingEventArgs e)
{
    if (e.ColumnIndex == 1 && e.RowIndex == -1)
    {
        e.PaintBackground(e.ClipBounds, false);

        Point pt = e.CellBounds.Location;  // where you want the bitmap in the cell

        int offset = (e.CellBounds.Width - this.images.ImageSize.Width) / 2;
        pt.X += offset;
        pt.Y += 1;
        this.images.Draw(e.Graphics, pt, 0);
        e.Handled = true;
    }
}

Answer 2

我需要更复杂一点的事情 - 在一些列标题中的文本前面添加关于列对齐的图像。

您需要实施自己的System.Windows.Forms.DataGridViewColumnHeaderCell并替换ColumnHeaderCell：

// Create header and set up image
YourDataGridViewColumnHeaderCell headerCell = new YourDataGridViewColumnHeaderCell();
headerCell.Image = something;

// Create column
DataGridViewColumn yourColumn = new DataGridViewTextBoxColumn(); 
// ...
yourColumn.ColumnHeaderCell = new headerCell;

现在有趣的部分（列标题的实现）：

class YourDataGridViewColumnHeaderCell : System.Windows.Forms.DataGridViewColumnHeaderCell
{
    // Set up image as you want
    System.Drawing.Image Image { get; set; }
}

现在我们要添加Paint()方法。唯一棘手的部分是使用System.Windows.Forms.DataGridViewPaintParts。

protected override void Paint( Graphics graphics, Rectangle clipBounds, Rectangle cellBounds, int rowIndex, DataGridViewElementStates dataGridViewElementState,
    object value, object formattedValue, string errorText, DataGridViewCellStyle cellStyle, DataGridViewAdvancedBorderStyle advancedBorderStyle,
    DataGridViewPaintParts paintParts )
{
    // Outside header or without an image, use default painting
    if ((rowIndex != -1) || (Image == null)) {
        base.Paint( graphics, clipBounds, cellBounds, rowIndex, dataGridViewElementState, value, formattedValue, errorText, cellStyle, advancedBorderStyle, paintParts );
        return;
    }

    // Borders, background, focus selection can remain the same
    // But Foreground will have different image
    base.Paint( graphics, clipBounds, cellBounds, rowIndex, dataGridViewElementState, value, formattedValue, errorText, cellStyle,
        advancedBorderStyle, paintParts & ~DataGridViewPaintParts.ContentForeground );

    // Repainting of content background (that's where we want to place our image)
    if ((paintParts & DataGridViewPaintParts.ContentBackground) != DataGridViewPaintParts.None) {
        // +4 is hardcoded margin 
        Point bounds = new Point( cellBounds.X + 4, cellBounds.Y );

        // Handle vertical alignment correctly
        switch (cellStyle.Alignment) {
            // Top
            case DataGridViewContentAlignment.TopLeft:
            case DataGridViewContentAlignment.TopCenter:
            case DataGridViewContentAlignment.TopRight:
                // Already set
                break;

            // Middle
            case DataGridViewContentAlignment.MiddleLeft:
            case DataGridViewContentAlignment.MiddleCenter:
            case DataGridViewContentAlignment.MiddleRight:
                bounds.Y = cellBounds.Y + (cellBounds.Height - Image.Height) / 2;
                break;

            // Bottom
            case DataGridViewContentAlignment.BottomLeft:
            case DataGridViewContentAlignment.BottomCenter:
            case DataGridViewContentAlignment.BottomRight:
                bounds.Y = cellBounds.Y + (cellBounds.Height - Image.Height);
                break;

        }
        graphics.DrawImage( Image, bounds );
    }

    // Foreground should be shifted by left image margin + image.width + right 
    // image margin and of course target spot should be a bit smaller
    if ((paintParts & DataGridViewPaintParts.ContentForeground) != DataGridViewPaintParts.None) {
        Rectangle newCellBounds = new Rectangle( cellBounds.X + 4 + Image.Width + 4, cellBounds.Y, cellBounds.Width - Image.Width - 8, cellBounds.Height );
        base.Paint( graphics, clipBounds, newCellBounds, rowIndex, dataGridViewElementState, value, formattedValue, errorText, cellStyle,
            advancedBorderStyle, DataGridViewPaintParts.ContentForeground );
    }

}

如果您要将AutoSizeColumnsMode设置为DataGridViewAutoSizeColumnsMode.ColumnHeaders（因此您需要自动调整图片和文字），您需要覆盖DataGridViewColumnHeaderCell.GetPreferredSize。我通过使用基本实现并向其添加Image.Width + Padding来完成此操作。

protected override Size GetPreferredSize( Graphics graphics, DataGridViewCellStyle cellStyle, int rowIndex,Size constraintSize )
{
    // Load up original image
    Size original = base.GetPreferredSize( graphics, cellStyle, rowIndex, constraintSize );

    // Ensure the image is set and that we are working on header
    if ((rowIndex != -1) || (Image == null)) {
        return original;
    }

    // -1 is reserved value
    if (original.Width < 0) {
        return original;
    }
    return new Size( original.Width + Image.Width + 4, original.Height );
}

注意 ：我花了几个小时在.NET sources挖掘，直到我发现了这一点。希望你没必要。

Answer 3

试试这个：

Private Sub DataGridView1_CellPainting(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DataGridViewCellPaintingEventArgs) Handles DataGridView1.CellPainting
        If e.RowIndex > -1 Then

            If e.ColumnIndex = -1 Then
                e.Paint(e.CellBounds, DataGridViewPaintParts.Focus And Not DataGridViewPaintParts.ContentForeground)
                DataGridView1.RowHeadersBorderStyle = DataGridViewHeaderBorderStyle.Single
                e.Graphics.DrawImage(IconImg, e.CellBounds)
                e.Handled = True
                'DataGridView1.RowHeadersWidth = 100
                'DataGridView1.ColumnHeadersHeight = 25
            End If

        End If

Answer 4

试试这段代码：

    Private Sub DataGridView1_CellPainting(ByVal sender As System.Object, _
            ByVal e As System.Windows.Forms.DataGridViewCellPaintingEventArgs) _
            Handles DataGridView1.CellPainting
        If e.RowIndex = -1 AndAlso e.ColumnIndex = DataGridView1.Columns.Count - 1 Then
            e.Paint(e.CellBounds, DataGridViewPaintParts.All And Not DataGridViewPaintParts.ContentForeground)
            e.Graphics.DrawImage(IconImg, e.CellBounds)
            e.Handled = True
        End If
    End Sub

如果您已阅读完整文章，请执行此检查此链接：

http://www.authorcode.com/add-image-on-datagridview-column-header-in-vb-net/

如何在datagridview列标题中显示图像？

4 个答案: