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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

DataGridView 控件提供了多种使用属性、事件以及伴随类自定义其外观和行为的方法。 有时候，您可能需要您的单元格具有这些功能之外的其他功能。 您可以创建自己的自定义 DataGridViewCell 类以提供扩展功能。

通过以 DataGridViewCell 基类或其某个派生类为基础进行派生，您可以创建自定义的 DataGridViewCell 类。 虽然可以在任何类型的列中显示任何类型的单元格，但是通常您还需要创建专用于显示单元格类型的自定义 DataGridViewColumn 类。 列类派生自 DataGridViewColumn 或其某个派生类型。

在下面的代码示例中，您将创建一个名为 DataGridViewRolloverCell 的自定义单元格类，该类检测鼠标何时进入和离开单元格边界。 当鼠标位于该单元格的边界内时，将绘制一个内嵌的矩形。 此新类型派生自 DataGridViewTextBoxCell，并且其行为在所有其他方面都与其基类相同。 伴随列类名为 DataGridViewRolloverColumn。

若要使用这些类，请创建一个包含 DataGridView 控件的窗体，将一个或多个 DataGridViewRolloverColumn 对象添加到 Columns 集合，并将包含值的行填入该控件。

提示

如果添加了空行，则此示例将无法正确运行。 例如，当您通过设置 RowCount 属性来向控件添加行时，就会创建空行。 这是因为在此情况下添加的行是自动共享的，这意味着只有在单击各个单元格之后，DataGridViewRolloverCell 对象才会实例化，从而使关联的行变为非共享状态。

因为此类型的单元格自定义要求使用非共享的行，因此它不适合用于大型数据集。 有关行共享的更多信息，请参见 缩放 Windows 窗体 DataGridView 控件的最佳做法。

提示

当从 DataGridViewCell 或 DataGridViewColumn 派生并向派生类添加新属性时，请确保重写 Clone 方法以便在克隆操作期间复制新属性。 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中。

自定义 DataGridView 控件中的单元格和列

  1. 从 DataGridViewTextBoxCell 类型派生一个名为 DataGridViewRolloverCell 的新的单元格类。

    Public Class DataGridViewRolloverCell
    Inherits DataGridViewTextBoxCell


...


End Class

    public class DataGridViewRolloverCell : DataGridViewTextBoxCell
{


...


}

  2. 重写 DataGridViewRolloverCell 类中的 Paint 方法。 在该重写中，首先调用基类实现，该实现处理寄宿文本框功能。 然后使用该控件的 PointToClient 方法将光标位置（屏幕坐标）转换为 DataGridView 工作区的坐标。 如果鼠标坐标落在单元格的边界以内，则绘制内嵌的矩形。

    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

    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);
    }
}

  3. 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 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

    // 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);
}

  4. 从 DataGridViewColumn 类型派生一个名为 DataGridViewRolloverCellColumn 的新类。 在构造函数中，将一个新的 DataGridViewRolloverCell 对象分配给其 CellTemplate 属性。

    Public Class DataGridViewRolloverCellColumn
    Inherits DataGridViewColumn

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

End Class

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

示例

完整的代码示例包含一个小型的测试窗体，该窗体演示了自定义单元格类型的行为。

Imports System
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

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();
    }
}

编译代码

此示例需要：

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

有关从 Visual Basic 或 Visual C# 的命令行生成此示例的信息，请参见从命令行生成 (Visual Basic) 或在命令行上使用 csc.exe 生成。 也可以通过将代码粘贴到新项目，在 Visual Studio 中生成此示例。 有关更多信息，请参见 如何：使用 Visual Studio 编译和运行完整的 Windows 窗体代码示例 和 如何：使用 Visual Studio 编译和运行完整的 Windows 窗体代码示例 和 如何：使用 Visual Studio 编译和运行完整的 Windows 窗体代码示例 和 如何：使用 Visual Studio 编译和运行完整的 Windows 窗体代码示例 和 如何：使用 Visual Studio 编译和运行完整的 Windows 窗体代码示例.

请参见

参考

DataGridView

DataGridViewCell

DataGridViewColumn

概念

DataGridView 控件体系结构（Windows 窗体）

Windows 窗体 DataGridView 控件中的列类型

缩放 Windows 窗体 DataGridView 控件的最佳做法

其他资源

自定义 Windows 窗体 DataGridView 控件