如何：通过扩展 Windows 窗体 DataGridView 控件中单元格和列的行为和外观对其进行自定义

项目
05/04/2023

DataGridView 控件提供使用属性、事件和伴生类自定义其外观和行为的多种方式。有时，你可能对这些功能不提供的单元格有要求。你可以创建自己的自定义 DataGridViewCell 类以提供扩展功能。

你可以通过从 DataGridViewCell 基类或其派生类之一派生创建自定义 DataGridViewCell 类。尽管可以在任何类型的列中显示任何类型的单元格，但通常仍会创建一个专用于显示单元格类型的自定义 DataGridViewColumn 类。列类派生自 DataGridViewColumn 或其派生类之一。

在以下代码示例中，你将创建一个名为 DataGridViewRolloverCell 的自定义单元格类，用于检测鼠标进入和离开单元格边界的时间。当鼠标位于单元格的边界内时，会绘制一个内嵌的矩形。这个新类型派生自 DataGridViewTextBoxCell，在所有其他方面均表现为其基类。伴生列类称为 DataGridViewRolloverColumn。

若要使用这些类，可创建一个包含 DataGridView 控件的窗体，向 Columns 集合添加一个或多个 DataGridViewRolloverColumn 对象，并用包含值的行填充该控件。

注意

如果添加空行，此示例将无法正常工作。例如，当你通过设置 RowCount 属性将行添加到该控件时，则会创建空行。这是因为在这种情况下添加的行将被自动共享，即在你单击一个单元格之后才会实例化 DataGridViewRolloverCell 对象，这就导致关联的行变为非共享。

由于这种类型的单元格自定义需要非共享行，因此其不适用于大型数据集。有关行共享的详细信息，请参阅缩放 Windows 窗体 DataGridView 控件的最佳做法。

注意

当从 DataGridViewCell 或 DataGridViewColumn 进行派生并将新属性添加到派生的类时，请确保重写 Clone 方法以在克隆操作过程中复制新属性。还应调用基类的 Clone 方法，以便将基类的属性复制到新的单元格或列。

自定义 DataGridView 控件中的单元格和列

从 DataGridViewTextBoxCell 类型派生一个名为 DataGridViewRolloverCell 的新单元格类。

public class DataGridViewRolloverCell : DataGridViewTextBoxCell
{

Public Class DataGridViewRolloverCell
    Inherits DataGridViewTextBoxCell

End Class

重写 Paint 类中的 DataGridViewRolloverCell 方法。在重写时，首先调用基类实现，基类实现处理托管文本框的功能。然后使用控件的 PointToClient 方法，将光标位置（在屏幕坐标中）转换为 DataGridView 客户端区域的坐标。如果鼠标坐标位于单元格的边界之内，则绘制内嵌矩形。

protected override void Paint(
    Graphics graphics,
    Rectangle clipBounds,
    Rectangle cellBounds,
    int rowIndex,
    DataGridViewElementStates cellState,
    object value,
    object formattedValue,
    string errorText,
    DataGridViewCellStyle cellStyle,
    DataGridViewAdvancedBorderStyle advancedBorderStyle,
    DataGridViewPaintParts paintParts)
{
    // Call the base class method to paint the default cell appearance.
    base.Paint(graphics, clipBounds, cellBounds, rowIndex, cellState,
        value, formattedValue, errorText, cellStyle,
        advancedBorderStyle, paintParts);

    // Retrieve the client location of the mouse pointer.
    Point cursorPosition =
        this.DataGridView.PointToClient(Cursor.Position);

    // If the mouse pointer is over the current cell, draw a custom border.
    if (cellBounds.Contains(cursorPosition))
    {
        Rectangle newRect = new Rectangle(cellBounds.X + 1,
            cellBounds.Y + 1, cellBounds.Width - 4,
            cellBounds.Height - 4);
        graphics.DrawRectangle(Pens.Red, newRect);
    }
}

Protected Overrides Sub Paint( _
    ByVal graphics As Graphics, _
    ByVal clipBounds As Rectangle, _
    ByVal cellBounds As Rectangle, _
    ByVal rowIndex As Integer, _
    ByVal elementState As DataGridViewElementStates, _
    ByVal value As Object, _
    ByVal formattedValue As Object, _
    ByVal errorText As String, _
    ByVal cellStyle As DataGridViewCellStyle, _
    ByVal advancedBorderStyle As DataGridViewAdvancedBorderStyle, _
    ByVal paintParts As DataGridViewPaintParts)

    ' Call the base class method to paint the default cell appearance.
    MyBase.Paint(graphics, clipBounds, cellBounds, rowIndex, elementState, _
        value, formattedValue, errorText, cellStyle, _
        advancedBorderStyle, paintParts)

    ' Retrieve the client location of the mouse pointer.
    Dim cursorPosition As Point = _
        Me.DataGridView.PointToClient(Cursor.Position)

    ' If the mouse pointer is over the current cell, draw a custom border.
    If cellBounds.Contains(cursorPosition) Then
        Dim newRect As New Rectangle(cellBounds.X + 1, _
            cellBounds.Y + 1, cellBounds.Width - 4, _
            cellBounds.Height - 4)
        graphics.DrawRectangle(Pens.Red, newRect)
    End If

End Sub

重写 DataGridViewRolloverCell 类中的 OnMouseEnter 和 OnMouseLeave 方法，以强制单元格在鼠标指针进入或离开它们时重新绘制自己。

// Force the cell to repaint itself when the mouse pointer enters it.
protected override void OnMouseEnter(int rowIndex)
{
    this.DataGridView.InvalidateCell(this);
}

// Force the cell to repaint itself when the mouse pointer leaves it.
protected override void OnMouseLeave(int rowIndex)
{
    this.DataGridView.InvalidateCell(this);
}

' Force the cell to repaint itself when the mouse pointer enters it.
Protected Overrides Sub OnMouseEnter(ByVal rowIndex As Integer)
    Me.DataGridView.InvalidateCell(Me)
End Sub

' Force the cell to repaint itself when the mouse pointer leaves it.
Protected Overrides Sub OnMouseLeave(ByVal rowIndex As Integer)
    Me.DataGridView.InvalidateCell(Me)
End Sub

从 DataGridViewColumn 类型派生一个名为 DataGridViewRolloverCellColumn 的新类。在构造函数中，向其 CellTemplate 属性分配一个新的 DataGridViewRolloverCell 对象。

public class DataGridViewRolloverCellColumn : DataGridViewColumn
{
    public DataGridViewRolloverCellColumn()
    {
        this.CellTemplate = new DataGridViewRolloverCell();
    }
}

Public Class DataGridViewRolloverCellColumn
    Inherits DataGridViewColumn

    Public Sub New()
        Me.CellTemplate = New DataGridViewRolloverCell()
    End Sub

End Class

示例

完整的代码示例包含一个小型测试窗体，用于演示自定义单元格类型的行为。

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

class Form1 : Form
{
    [STAThreadAttribute()]
    public static void Main()
    {
        Application.Run(new Form1());
    }

    public Form1()
    {
        DataGridView dataGridView1 = new DataGridView();
        DataGridViewRolloverCellColumn col =
            new DataGridViewRolloverCellColumn();
        dataGridView1.Columns.Add(col);
        dataGridView1.Rows.Add(new string[] { "" });
        dataGridView1.Rows.Add(new string[] { "" });
        dataGridView1.Rows.Add(new string[] { "" });
        dataGridView1.Rows.Add(new string[] { "" });
        this.Controls.Add(dataGridView1);
        this.Text = "DataGridView rollover-cell demo";
    }
}

public class DataGridViewRolloverCell : DataGridViewTextBoxCell
{
    protected override void Paint(
        Graphics graphics,
        Rectangle clipBounds,
        Rectangle cellBounds,
        int rowIndex,
        DataGridViewElementStates cellState,
        object value,
        object formattedValue,
        string errorText,
        DataGridViewCellStyle cellStyle,
        DataGridViewAdvancedBorderStyle advancedBorderStyle,
        DataGridViewPaintParts paintParts)
    {
        // Call the base class method to paint the default cell appearance.
        base.Paint(graphics, clipBounds, cellBounds, rowIndex, cellState,
            value, formattedValue, errorText, cellStyle,
            advancedBorderStyle, paintParts);

        // Retrieve the client location of the mouse pointer.
        Point cursorPosition =
            this.DataGridView.PointToClient(Cursor.Position);

        // If the mouse pointer is over the current cell, draw a custom border.
        if (cellBounds.Contains(cursorPosition))
        {
            Rectangle newRect = new Rectangle(cellBounds.X + 1,
                cellBounds.Y + 1, cellBounds.Width - 4,
                cellBounds.Height - 4);
            graphics.DrawRectangle(Pens.Red, newRect);
        }
    }

    // Force the cell to repaint itself when the mouse pointer enters it.
    protected override void OnMouseEnter(int rowIndex)
    {
        this.DataGridView.InvalidateCell(this);
    }

    // Force the cell to repaint itself when the mouse pointer leaves it.
    protected override void OnMouseLeave(int rowIndex)
    {
        this.DataGridView.InvalidateCell(this);
    }

}

public class DataGridViewRolloverCellColumn : DataGridViewColumn
{
    public DataGridViewRolloverCellColumn()
    {
        this.CellTemplate = new DataGridViewRolloverCell();
    }
}

Imports System.Drawing
Imports System.Windows.Forms

Class Form1
    Inherits Form

    <STAThreadAttribute()> _
    Public Shared Sub Main()
        Application.Run(New Form1())
    End Sub

    Public Sub New()
        Dim dataGridView1 As New DataGridView()
        Dim col As New DataGridViewRolloverCellColumn()
        dataGridView1.Columns.Add(col)
        dataGridView1.Rows.Add(New String() {""})
        dataGridView1.Rows.Add(New String() {""})
        dataGridView1.Rows.Add(New String() {""})
        dataGridView1.Rows.Add(New String() {""})
        Me.Controls.Add(dataGridView1)
        Me.Text = "DataGridView rollover-cell demo"
    End Sub

End Class

Public Class DataGridViewRolloverCell
    Inherits DataGridViewTextBoxCell

    Protected Overrides Sub Paint( _
        ByVal graphics As Graphics, _
        ByVal clipBounds As Rectangle, _
        ByVal cellBounds As Rectangle, _
        ByVal rowIndex As Integer, _
        ByVal elementState As DataGridViewElementStates, _
        ByVal value As Object, _
        ByVal formattedValue As Object, _
        ByVal errorText As String, _
        ByVal cellStyle As DataGridViewCellStyle, _
        ByVal advancedBorderStyle As DataGridViewAdvancedBorderStyle, _
        ByVal paintParts As DataGridViewPaintParts)

        ' Call the base class method to paint the default cell appearance.
        MyBase.Paint(graphics, clipBounds, cellBounds, rowIndex, elementState, _
            value, formattedValue, errorText, cellStyle, _
            advancedBorderStyle, paintParts)

        ' Retrieve the client location of the mouse pointer.
        Dim cursorPosition As Point = _
            Me.DataGridView.PointToClient(Cursor.Position)

        ' If the mouse pointer is over the current cell, draw a custom border.
        If cellBounds.Contains(cursorPosition) Then
            Dim newRect As New Rectangle(cellBounds.X + 1, _
                cellBounds.Y + 1, cellBounds.Width - 4, _
                cellBounds.Height - 4)
            graphics.DrawRectangle(Pens.Red, newRect)
        End If

    End Sub

    ' Force the cell to repaint itself when the mouse pointer enters it.
    Protected Overrides Sub OnMouseEnter(ByVal rowIndex As Integer)
        Me.DataGridView.InvalidateCell(Me)
    End Sub

    ' Force the cell to repaint itself when the mouse pointer leaves it.
    Protected Overrides Sub OnMouseLeave(ByVal rowIndex As Integer)
        Me.DataGridView.InvalidateCell(Me)
    End Sub

End Class

Public Class DataGridViewRolloverCellColumn
    Inherits DataGridViewColumn

    Public Sub New()
        Me.CellTemplate = New DataGridViewRolloverCell()
    End Sub

End Class

编译代码

此示例需要：

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

如何：通过扩展 Windows 窗体 DataGridView 控件中单元格和列的行为和外观对其进行自定义

自定义 DataGridView 控件中的单元格和列

示例

编译代码

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