如何:自定义 Windows 窗体 DataGridView 控件中行的外观

通过处理 DataGridView.RowPrePaintDataGridView.RowPostPaint 事件之一或两者同时处理,可以控制 DataGridView 行的外观。 这些事件设计用于使你可以仅绘制想绘制的内容,同时使 DataGridView 控件绘制其余内容。 例如,如果要绘制自定义背景,则可以处理 DataGridView.RowPrePaint 事件并让各个单元格自行绘制自己的前景内容。 或者,还可以让单元格自行绘制,并在 DataGridView.RowPostPaint 事件的处理程序中添加自定义前景内容。 此外,还可以禁用单元格绘制,并在 DataGridView.RowPrePaint 事件处理程序中亲自绘制所有内容。

下面的代码示例实现两个事件的处理程序,以便提供渐变选区背景和某些跨多个列的自定义前景内容。

示例

using System;
using System.Drawing;
using System.Windows.Forms;

class DataGridViewRowPainting : Form
{
    private DataGridView dataGridView1 = new DataGridView();
    private Int32 oldRowIndex = 0;
    private const Int32 CUSTOM_CONTENT_HEIGHT = 30;

    [STAThreadAttribute()]
    public static void Main()
    {
        Application.Run(new DataGridViewRowPainting());
    }

    public DataGridViewRowPainting()
    {
        this.dataGridView1.Dock = DockStyle.Fill;
        this.Controls.Add(this.dataGridView1);
        this.Load += new EventHandler(DataGridViewRowPainting_Load);
        this.Text = "DataGridView row painting demo";
    }

    void DataGridViewRowPainting_Load(object sender, EventArgs e)
    {
        // Set a cell padding to provide space for the top of the focus
        // rectangle and for the content that spans multiple columns.
        Padding newPadding = new Padding(0, 1, 0, CUSTOM_CONTENT_HEIGHT);
        this.dataGridView1.RowTemplate.DefaultCellStyle.Padding = newPadding;

        // Set the selection background color to transparent so
        // the cell won't paint over the custom selection background.
        this.dataGridView1.RowTemplate.DefaultCellStyle.SelectionBackColor =
            Color.Transparent;

        // Set the row height to accommodate the content that
        // spans multiple columns.
        this.dataGridView1.RowTemplate.Height += CUSTOM_CONTENT_HEIGHT;

        // Initialize other DataGridView properties.
        this.dataGridView1.AllowUserToAddRows = false;
        this.dataGridView1.EditMode = DataGridViewEditMode.EditOnKeystrokeOrF2;
        this.dataGridView1.CellBorderStyle = DataGridViewCellBorderStyle.None;
        this.dataGridView1.SelectionMode =
            DataGridViewSelectionMode.FullRowSelect;

        // Set the column header names.
        this.dataGridView1.ColumnCount = 4;
        this.dataGridView1.Columns[0].Name = "Recipe";
        this.dataGridView1.Columns[0].SortMode =
            DataGridViewColumnSortMode.NotSortable;
        this.dataGridView1.Columns[1].Name = "Category";
        this.dataGridView1.Columns[2].Name = "Main Ingredients";
        this.dataGridView1.Columns[3].Name = "Rating";

        // Hide the column that contains the content that spans
        // multiple columns.
        this.dataGridView1.Columns[2].Visible = false;

        // Populate the rows of the DataGridView.
        string[] row1 = new string[]{"Meatloaf", "Main Dish",
            "1 lb. lean ground beef, 1/2 cup bread crumbs, " +
            "1/4 cup ketchup, 1/3 tsp onion powder, 1 clove of garlic, " +
            "1/2 pack onion soup mix, dash of your favorite BBQ Sauce",
            "****"};
        string[] row2 = new string[]{"Key Lime Pie", "Dessert",
            "lime juice, whipped cream, eggs, evaporated milk", "****"};
        string[] row3 = new string[]{"Orange-Salsa Pork Chops",
            "Main Dish", "pork chops, salsa, orange juice, pineapple", "****"};
        string[] row4 = new string[]{"Black Bean and Rice Salad",
            "Salad", "black beans, brown rice", "****"};
        string[] row5 = new string[]{"Chocolate Cheesecake",
            "Dessert", "cream cheese, unsweetened chocolate", "***"};
        string[] row6 = new string[]{"Black Bean Dip", "Appetizer",
            "black beans, sour cream, salsa, chips", "***"};
        object[] rows = new object[] { row1, row2, row3, row4, row5, row6 };
        foreach (string[] rowArray in rows)
        {
            this.dataGridView1.Rows.Add(rowArray);
        }

        // Adjust the row heights to accommodate the normal cell content.
        this.dataGridView1.AutoResizeRows(
            DataGridViewAutoSizeRowsMode.AllCellsExceptHeaders);

        // Attach handlers to DataGridView events.
        this.dataGridView1.ColumnWidthChanged += new
            DataGridViewColumnEventHandler(dataGridView1_ColumnWidthChanged);
        this.dataGridView1.RowPrePaint += new
            DataGridViewRowPrePaintEventHandler(dataGridView1_RowPrePaint);
        this.dataGridView1.RowPostPaint += new
            DataGridViewRowPostPaintEventHandler(dataGridView1_RowPostPaint);
        this.dataGridView1.CurrentCellChanged += new
            EventHandler(dataGridView1_CurrentCellChanged);
        this.dataGridView1.RowHeightChanged += new
            DataGridViewRowEventHandler(dataGridView1_RowHeightChanged);
    }

    // Forces the control to repaint itself when the user
    // manually changes the width of a column.
    void dataGridView1_ColumnWidthChanged(object sender,
        DataGridViewColumnEventArgs e)
    {
        this.dataGridView1.Invalidate();
    }

    // Forces the row to repaint itself when the user changes the
    // current cell. This is necessary to refresh the focus rectangle.
    void dataGridView1_CurrentCellChanged(object sender, EventArgs e)
    {
        if (oldRowIndex != -1)
        {
            this.dataGridView1.InvalidateRow(oldRowIndex);
        }
        oldRowIndex = this.dataGridView1.CurrentCellAddress.Y;
    }

    // Paints the custom selection background for selected rows.
    void dataGridView1_RowPrePaint(object sender,
            DataGridViewRowPrePaintEventArgs e)
    {
        // Do not automatically paint the focus rectangle.
        e.PaintParts &= ~DataGridViewPaintParts.Focus;

        // Determine whether the cell should be painted
        // with the custom selection background.
        if ((e.State & DataGridViewElementStates.Selected) ==
                    DataGridViewElementStates.Selected)
        {
            // Calculate the bounds of the row.
            Rectangle rowBounds = new Rectangle(
                this.dataGridView1.RowHeadersWidth, e.RowBounds.Top,
                this.dataGridView1.Columns.GetColumnsWidth(
                    DataGridViewElementStates.Visible) -
                this.dataGridView1.HorizontalScrollingOffset + 1,
                e.RowBounds.Height);

            // Paint the custom selection background.
            using (Brush backbrush =
                new System.Drawing.Drawing2D.LinearGradientBrush(rowBounds,
                    this.dataGridView1.DefaultCellStyle.SelectionBackColor,
                    e.InheritedRowStyle.ForeColor,
                    System.Drawing.Drawing2D.LinearGradientMode.Horizontal))
            {
                e.Graphics.FillRectangle(backbrush, rowBounds);
            }
        }
    }

    // Paints the content that spans multiple columns and the focus rectangle.
    void dataGridView1_RowPostPaint(object sender,
        DataGridViewRowPostPaintEventArgs e)
    {
        // Calculate the bounds of the row.
        Rectangle rowBounds = new Rectangle(
            this.dataGridView1.RowHeadersWidth, e.RowBounds.Top,
            this.dataGridView1.Columns.GetColumnsWidth(
                DataGridViewElementStates.Visible) -
            this.dataGridView1.HorizontalScrollingOffset + 1,
            e.RowBounds.Height);

        SolidBrush forebrush = null;
        try
        {
            // Determine the foreground color.
            if ((e.State & DataGridViewElementStates.Selected) ==
                DataGridViewElementStates.Selected)
            {
                forebrush = new SolidBrush(e.InheritedRowStyle.SelectionForeColor);
            }
            else
            {
                forebrush = new SolidBrush(e.InheritedRowStyle.ForeColor);
            }

            // Get the content that spans multiple columns.
            object recipe =
                this.dataGridView1.Rows.SharedRow(e.RowIndex).Cells[2].Value;

            if (recipe != null)
            {
                String text = recipe.ToString();

                // Calculate the bounds for the content that spans multiple
                // columns, adjusting for the horizontal scrolling position
                // and the current row height, and displaying only whole
                // lines of text.
                Rectangle textArea = rowBounds;
                textArea.X -= this.dataGridView1.HorizontalScrollingOffset;
                textArea.Width += this.dataGridView1.HorizontalScrollingOffset;
                textArea.Y += rowBounds.Height - e.InheritedRowStyle.Padding.Bottom;
                textArea.Height -= rowBounds.Height -
                    e.InheritedRowStyle.Padding.Bottom;
                textArea.Height = (textArea.Height / e.InheritedRowStyle.Font.Height) *
                    e.InheritedRowStyle.Font.Height;

                // Calculate the portion of the text area that needs painting.
                RectangleF clip = textArea;
                clip.Width -= this.dataGridView1.RowHeadersWidth + 1 - clip.X;
                clip.X = this.dataGridView1.RowHeadersWidth + 1;
                RectangleF oldClip = e.Graphics.ClipBounds;
                e.Graphics.SetClip(clip);

                // Draw the content that spans multiple columns.
                e.Graphics.DrawString(
                    text, e.InheritedRowStyle.Font, forebrush, textArea);

                e.Graphics.SetClip(oldClip);
            }
        }
        finally
        {
            forebrush.Dispose();
        }

        if (this.dataGridView1.CurrentCellAddress.Y == e.RowIndex)
        {
            // Paint the focus rectangle.
            e.DrawFocus(rowBounds, true);
        }
    }

    // Adjusts the padding when the user changes the row height so that
    // the normal cell content is fully displayed and any extra
    // height is used for the content that spans multiple columns.
    void dataGridView1_RowHeightChanged(object sender,
        DataGridViewRowEventArgs e)
    {
        // Calculate the new height of the normal cell content.
        Int32 preferredNormalContentHeight =
            e.Row.GetPreferredHeight(e.Row.Index,
            DataGridViewAutoSizeRowMode.AllCellsExceptHeader, true) -
            e.Row.DefaultCellStyle.Padding.Bottom;

        // Specify a new padding.
        Padding newPadding = e.Row.DefaultCellStyle.Padding;
        newPadding.Bottom = e.Row.Height - preferredNormalContentHeight;
        e.Row.DefaultCellStyle.Padding = newPadding;
    }
}
Imports System.Drawing
Imports System.Windows.Forms

Class DataGridViewRowPainting
    Inherits Form
    Private WithEvents dataGridView1 As New DataGridView()
    Private oldRowIndex As Int32 = 0
    Private Const CUSTOM_CONTENT_HEIGHT As Int32 = 30

    <STAThreadAttribute()> _
    Public Shared Sub Main()

        Application.Run(New DataGridViewRowPainting())

    End Sub

    Public Sub New()

        Me.dataGridView1.Dock = DockStyle.Fill
        Me.Controls.Add(Me.dataGridView1)
        Me.Text = "DataGridView row painting demo"

    End Sub

    Sub DataGridViewRowPainting_Load(ByVal sender As Object, _
        ByVal e As EventArgs) Handles Me.Load

        ' Set a cell padding to provide space for the top of the focus 
        ' rectangle and for the content that spans multiple columns. 
        Dim newPadding As New Padding(0, 1, 0, CUSTOM_CONTENT_HEIGHT)
        Me.dataGridView1.RowTemplate.DefaultCellStyle.Padding = newPadding

        ' Set the selection background color to transparent so 
        ' the cell won't paint over the custom selection background.
        Me.dataGridView1.RowTemplate.DefaultCellStyle.SelectionBackColor = _
            Color.Transparent

        ' Set the row height to accommodate the normal cell content and the 
        ' content that spans multiple columns.
        Me.dataGridView1.RowTemplate.Height += CUSTOM_CONTENT_HEIGHT

        ' Initialize other DataGridView properties.
        Me.dataGridView1.AllowUserToAddRows = False
        Me.dataGridView1.EditMode = DataGridViewEditMode.EditOnKeystrokeOrF2
        Me.dataGridView1.CellBorderStyle = DataGridViewCellBorderStyle.None
        Me.dataGridView1.SelectionMode = DataGridViewSelectionMode.FullRowSelect

        ' Set the column header names.
        Me.dataGridView1.ColumnCount = 4
        Me.dataGridView1.Columns(0).Name = "Recipe"
        Me.dataGridView1.Columns(0).SortMode = _
            DataGridViewColumnSortMode.NotSortable
        Me.dataGridView1.Columns(1).Name = "Category"
        Me.dataGridView1.Columns(2).Name = "Main Ingredients"
        Me.dataGridView1.Columns(3).Name = "Rating"

        ' Hide the column that contains the content that spans 
        ' multiple columns.
        Me.dataGridView1.Columns(2).Visible = False

        ' Populate the rows of the DataGridView.
        Dim row1() As String = {"Meatloaf", "Main Dish", _
            "1 lb. lean ground beef, 1/2 cup bread crumbs, " + _
            "1/4 cup ketchup, 1/3 tsp onion powder, 1 clove of garlic, " + _
            "1/2 pack onion soup mix, dash of your favorite BBQ Sauce", "****"}
        Dim row2() As String = {"Key Lime Pie", "Dessert", _
            "lime juice, whipped cream, eggs, evaporated milk", "****"}
        Dim row3() As String = {"Orange-Salsa Pork Chops", "Main Dish", _
            "pork chops, salsa, orange juice, pineapple", "****"}
        Dim row4() As String = {"Black Bean and Rice Salad", "Salad", _
            "black beans, brown rice", "****"}
        Dim row5() As String = {"Chocolate Cheesecake", "Dessert", _
            "cream cheese, unsweetened chocolate", "***"}
        Dim row6() As String = {"Black Bean Dip", "Appetizer", _
            "black beans, sour cream, salsa, chips", "***"}
        Dim rows() As Object = {row1, row2, row3, row4, row5, row6}
        Dim rowArray As String()
        For Each rowArray In rows
            Me.dataGridView1.Rows.Add(rowArray)
        Next rowArray

        ' Adjust the row heights to accommodate the normal cell content.
        Me.dataGridView1.AutoResizeRows( _
            DataGridViewAutoSizeRowsMode.AllCellsExceptHeaders)
    End Sub

    ' Forces the control to repaint itself when the user 
    ' manually changes the width of a column.
    Sub dataGridView1_ColumnWidthChanged(ByVal sender As Object, _
        ByVal e As DataGridViewColumnEventArgs) _
        Handles dataGridView1.ColumnWidthChanged

        Me.dataGridView1.Invalidate()

    End Sub

    ' Forces the row to repaint itself when the user changes the 
    ' current cell. This is necessary to refresh the focus rectangle.
    Sub dataGridView1_CurrentCellChanged(ByVal sender As Object, _
        ByVal e As EventArgs) Handles dataGridView1.CurrentCellChanged

        If oldRowIndex <> -1 Then
            Me.dataGridView1.InvalidateRow(oldRowIndex)
        End If
        oldRowIndex = Me.dataGridView1.CurrentCellAddress.Y

    End Sub

    ' Paints the custom selection background for selected rows.
    Sub dataGridView1_RowPrePaint(ByVal sender As Object, _
        ByVal e As DataGridViewRowPrePaintEventArgs) _
        Handles dataGridView1.RowPrePaint

        ' Do not automatically paint the focus rectangle.
        e.PaintParts = e.PaintParts And Not DataGridViewPaintParts.Focus

        ' Determine whether the cell should be painted with the 
        ' custom selection background.
        If (e.State And DataGridViewElementStates.Selected) = _
            DataGridViewElementStates.Selected Then

            ' Calculate the bounds of the row.
            Dim rowBounds As New Rectangle( _
                Me.dataGridView1.RowHeadersWidth, e.RowBounds.Top, _
                Me.dataGridView1.Columns.GetColumnsWidth( _
                DataGridViewElementStates.Visible) - _
                Me.dataGridView1.HorizontalScrollingOffset + 1, _
                e.RowBounds.Height)

            ' Paint the custom selection background.
            Dim backbrush As New _
                System.Drawing.Drawing2D.LinearGradientBrush(rowBounds, _
                Me.dataGridView1.DefaultCellStyle.SelectionBackColor, _
                e.InheritedRowStyle.ForeColor, _
                System.Drawing.Drawing2D.LinearGradientMode.Horizontal)
            Try
                e.Graphics.FillRectangle(backbrush, rowBounds)
            Finally
                backbrush.Dispose()
            End Try
        End If

    End Sub

    ' Paints the content that spans multiple columns and the focus rectangle.
    Sub dataGridView1_RowPostPaint(ByVal sender As Object, _
        ByVal e As DataGridViewRowPostPaintEventArgs) _
        Handles dataGridView1.RowPostPaint

        ' Calculate the bounds of the row.
        Dim rowBounds As New Rectangle(Me.dataGridView1.RowHeadersWidth, _
            e.RowBounds.Top, Me.dataGridView1.Columns.GetColumnsWidth( _
            DataGridViewElementStates.Visible) - _
            Me.dataGridView1.HorizontalScrollingOffset + 1, e.RowBounds.Height)

        Dim forebrush As SolidBrush = Nothing
        Try
            ' Determine the foreground color.
            If (e.State And DataGridViewElementStates.Selected) = _
                DataGridViewElementStates.Selected Then

                forebrush = New SolidBrush(e.InheritedRowStyle.SelectionForeColor)
            Else
                forebrush = New SolidBrush(e.InheritedRowStyle.ForeColor)
            End If

            ' Get the content that spans multiple columns.
            Dim recipe As Object = _
                Me.dataGridView1.Rows.SharedRow(e.RowIndex).Cells(2).Value

            If (recipe IsNot Nothing) Then
                Dim text As String = recipe.ToString()

                ' Calculate the bounds for the content that spans multiple 
                ' columns, adjusting for the horizontal scrolling position 
                ' and the current row height, and displaying only whole
                ' lines of text.
                Dim textArea As Rectangle = rowBounds
                textArea.X -= Me.dataGridView1.HorizontalScrollingOffset
                textArea.Width += Me.dataGridView1.HorizontalScrollingOffset
                textArea.Y += rowBounds.Height - e.InheritedRowStyle.Padding.Bottom
                textArea.Height -= rowBounds.Height - e.InheritedRowStyle.Padding.Bottom
                textArea.Height = (textArea.Height \ e.InheritedRowStyle.Font.Height) * _
                    e.InheritedRowStyle.Font.Height

                ' Calculate the portion of the text area that needs painting.
                Dim clip As RectangleF = textArea
                clip.Width -= Me.dataGridView1.RowHeadersWidth + 1 - clip.X
                clip.X = Me.dataGridView1.RowHeadersWidth + 1
                Dim oldClip As RectangleF = e.Graphics.ClipBounds
                e.Graphics.SetClip(clip)

                ' Draw the content that spans multiple columns.
                e.Graphics.DrawString(text, e.InheritedRowStyle.Font, forebrush, _
                    textArea)

                e.Graphics.SetClip(oldClip)
            End If
        Finally
            forebrush.Dispose()
        End Try

        If Me.dataGridView1.CurrentCellAddress.Y = e.RowIndex Then
            ' Paint the focus rectangle.
            e.DrawFocus(rowBounds, True)
        End If

    End Sub

    ' Adjusts the padding when the user changes the row height so that 
    ' the normal cell content is fully displayed and any extra
    ' height is used for the content that spans multiple columns.
    Sub dataGridView1_RowHeightChanged(ByVal sender As Object, _
        ByVal e As DataGridViewRowEventArgs) _
        Handles dataGridView1.RowHeightChanged

        ' Calculate the new height of the normal cell content.
        Dim preferredNormalContentHeight As Int32 = _
            e.Row.GetPreferredHeight(e.Row.Index, _
            DataGridViewAutoSizeRowMode.AllCellsExceptHeader, True) - _
            e.Row.DefaultCellStyle.Padding.Bottom()

        ' Specify a new padding.
        Dim newPadding As Padding = e.Row.DefaultCellStyle.Padding
        newPadding.Bottom = e.Row.Height - preferredNormalContentHeight
        e.Row.DefaultCellStyle.Padding = newPadding

    End Sub

End Class

编译代码

此示例需要:

  • 对 System、System.Drawing 和 System.Windows.Forms 程序集的引用。

另请参阅