HOW TO：停用 Windows Form DataGridView 控制項按鈕資料行中的按鈕

DataGridView 控制項包含 DataGridViewButtonCell 類別，可以顯示具有使用介面 (UI) (例如按鈕) 的儲存格。但是，DataGridViewButtonCell 並不提供方法來停用儲存格所顯示按鈕的外觀。

下列程式碼範例示範如何自訂 DataGridViewButtonCell 類別，以顯示可呈現為停用狀況的按鈕。這個範例定義新的儲存格型別 DataGridViewDisableButtonCell，這個型別是衍生自 DataGridViewButtonCell。這個儲存格型別提供了新的 Enabled 屬性，這個屬性可設定為 false，以便在儲存格中繪製停用的按鈕。此範例也定義新的資料行型別 DataGridViewDisableButtonColumn，這個型別會顯示 DataGridViewDisableButtonCell 物件。若要示範這個新儲存格和資料行型別，在父 DataGridView 中每個 DataGridViewCheckBoxCell 的目前值會決定在相同的資料列中，DataGridViewDisableButtonCell 的 Enabled 屬性是否為 true 或 false。

注意事項
當您從 DataGridViewCell 或 DataGridViewColumn 衍生，並加入新屬性至衍生類別時，請務必覆寫 Clone 方法，以便於複製作業期間複製新屬性。您也應該呼叫基底類別的 Clone 方法，以便複製基底類別的屬性至新儲存格或資料行。

範例

Imports System
Imports System.Drawing
Imports System.Windows.Forms
Imports System.Windows.Forms.VisualStyles

Class Form1
    Inherits Form
    Private WithEvents dataGridView1 As New DataGridView()

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

    Public Sub New()
        Me.AutoSize = True
    End Sub

    Public Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs) _
        Handles Me.Load

        Dim column0 As New DataGridViewCheckBoxColumn()
        Dim column1 As New DataGridViewDisableButtonColumn()
        column0.Name = "CheckBoxes"
        column1.Name = "Buttons"
        dataGridView1.Columns.Add(column0)
        dataGridView1.Columns.Add(column1)

        dataGridView1.RowCount = 8
        dataGridView1.AutoSize = True
        dataGridView1.AllowUserToAddRows = False
        dataGridView1.ColumnHeadersDefaultCellStyle.Alignment = _
            DataGridViewContentAlignment.MiddleCenter

        ' Set the text for each button.
        Dim i As Integer
        For i = 0 To dataGridView1.RowCount - 1
            dataGridView1.Rows(i).Cells("Buttons").Value = _
                "Button " + i.ToString()
        Next i

        Me.Controls.Add(dataGridView1)

    End Sub

    ' This event handler manually raises the CellValueChanged event
    ' by calling the CommitEdit method.
    Sub dataGridView1_CurrentCellDirtyStateChanged( _
        ByVal sender As Object, ByVal e As EventArgs) _
        Handles dataGridView1.CurrentCellDirtyStateChanged

        If dataGridView1.IsCurrentCellDirty Then
            dataGridView1.CommitEdit(DataGridViewDataErrorContexts.Commit)
        End If
    End Sub

    ' If a check box cell is clicked, this event handler disables  
    ' or enables the button in the same row as the clicked cell.
    Public Sub dataGridView1_CellValueChanged(ByVal sender As Object, _
        ByVal e As DataGridViewCellEventArgs) _
        Handles dataGridView1.CellValueChanged

        If dataGridView1.Columns(e.ColumnIndex).Name = "CheckBoxes" Then
            Dim buttonCell As DataGridViewDisableButtonCell = _
                CType(dataGridView1.Rows(e.RowIndex).Cells("Buttons"), _
                DataGridViewDisableButtonCell)

            Dim checkCell As DataGridViewCheckBoxCell = _
                CType(dataGridView1.Rows(e.RowIndex).Cells("CheckBoxes"), _
                DataGridViewCheckBoxCell)
            buttonCell.Enabled = Not CType(checkCell.Value, [Boolean])

            dataGridView1.Invalidate()
        End If
    End Sub

    ' If the user clicks on an enabled button cell, this event handler  
    ' reports that the button is enabled.
    Sub dataGridView1_CellClick(ByVal sender As Object, _
        ByVal e As DataGridViewCellEventArgs) _
        Handles dataGridView1.CellClick

        If dataGridView1.Columns(e.ColumnIndex).Name = "Buttons" Then
            Dim buttonCell As DataGridViewDisableButtonCell = _
                CType(dataGridView1.Rows(e.RowIndex).Cells("Buttons"), _
                DataGridViewDisableButtonCell)

            If buttonCell.Enabled Then
                MsgBox(dataGridView1.Rows(e.RowIndex). _
                    Cells(e.ColumnIndex).Value.ToString() + _
                    " is enabled")
            End If
        End If
    End Sub

End Class

Public Class DataGridViewDisableButtonColumn
    Inherits DataGridViewButtonColumn

    Public Sub New()
        Me.CellTemplate = New DataGridViewDisableButtonCell()
    End Sub
End Class

Public Class DataGridViewDisableButtonCell
    Inherits DataGridViewButtonCell

    Private enabledValue As Boolean
    Public Property Enabled() As Boolean
        Get
            Return enabledValue
        End Get
        Set(ByVal value As Boolean)
            enabledValue = value
        End Set
    End Property

    ' Override the Clone method so that the Enabled property is copied.
    Public Overrides Function Clone() As Object
        Dim Cell As DataGridViewDisableButtonCell = _
            CType(MyBase.Clone(), DataGridViewDisableButtonCell)
        Cell.Enabled = Me.Enabled
        Return Cell
    End Function

    ' By default, enable the button cell.
    Public Sub New()
        Me.enabledValue = True
    End Sub

    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)

        ' The button cell is disabled, so paint the border,  
        ' background, and disabled button for the cell.
        If Not Me.enabledValue Then

            ' Draw the background of the cell, if specified.
            If (paintParts And DataGridViewPaintParts.Background) = _
                DataGridViewPaintParts.Background Then

                Dim cellBackground As New SolidBrush(cellStyle.BackColor)
                graphics.FillRectangle(cellBackground, cellBounds)
                cellBackground.Dispose()
            End If

            ' Draw the cell borders, if specified.
            If (paintParts And DataGridViewPaintParts.Border) = _
                DataGridViewPaintParts.Border Then

                PaintBorder(graphics, clipBounds, cellBounds, cellStyle, _
                    advancedBorderStyle)
            End If

            ' Calculate the area in which to draw the button.
            Dim buttonArea As Rectangle = cellBounds
            Dim buttonAdjustment As Rectangle = _
                Me.BorderWidths(advancedBorderStyle)
            buttonArea.X += buttonAdjustment.X
            buttonArea.Y += buttonAdjustment.Y
            buttonArea.Height -= buttonAdjustment.Height
            buttonArea.Width -= buttonAdjustment.Width

            ' Draw the disabled button.                
            ButtonRenderer.DrawButton(graphics, buttonArea, _
                PushButtonState.Disabled)

            ' Draw the disabled button text. 
            If TypeOf Me.FormattedValue Is String Then
                TextRenderer.DrawText(graphics, CStr(Me.FormattedValue), _
                    Me.DataGridView.Font, buttonArea, SystemColors.GrayText)
            End If

        Else
            ' The button cell is enabled, so let the base class 
            ' handle the painting.
            MyBase.Paint(graphics, clipBounds, cellBounds, rowIndex, _
                elementState, value, formattedValue, errorText, _
                cellStyle, advancedBorderStyle, paintParts)
        End If
    End Sub

End Class

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

class Form1 : Form
{
    private DataGridView dataGridView1 = new DataGridView();

    [STAThread]
    public static void Main()
    {
        Application.EnableVisualStyles();
        Application.Run(new Form1());
    }

    public Form1()
    {
        this.AutoSize = true;
        this.Load += new EventHandler(Form1_Load);
    }

    public void Form1_Load(object sender, EventArgs e)
    {
        DataGridViewCheckBoxColumn column0 =
            new DataGridViewCheckBoxColumn();
        DataGridViewDisableButtonColumn column1 =
            new DataGridViewDisableButtonColumn();
        column0.Name = "CheckBoxes";
        column1.Name = "Buttons";
        dataGridView1.Columns.Add(column0);
        dataGridView1.Columns.Add(column1);
        dataGridView1.RowCount = 8;
        dataGridView1.AutoSize = true;
        dataGridView1.AllowUserToAddRows = false;
        dataGridView1.ColumnHeadersDefaultCellStyle.Alignment =
            DataGridViewContentAlignment.MiddleCenter;

        // Set the text for each button.
        for (int i = 0; i < dataGridView1.RowCount; i++)
        {
            dataGridView1.Rows[i].Cells["Buttons"].Value =
                "Button " + i.ToString();
        }

        dataGridView1.CellValueChanged +=
            new DataGridViewCellEventHandler(dataGridView1_CellValueChanged);
        dataGridView1.CurrentCellDirtyStateChanged +=
            new EventHandler(dataGridView1_CurrentCellDirtyStateChanged);
        dataGridView1.CellClick +=
            new DataGridViewCellEventHandler(dataGridView1_CellClick);

        this.Controls.Add(dataGridView1);
    }

    // This event handler manually raises the CellValueChanged event
    // by calling the CommitEdit method.
    void dataGridView1_CurrentCellDirtyStateChanged(object sender,
        EventArgs e)
    {
        if (dataGridView1.IsCurrentCellDirty)
        {
            dataGridView1.CommitEdit(DataGridViewDataErrorContexts.Commit);
        }
    }

    // If a check box cell is clicked, this event handler disables  
    // or enables the button in the same row as the clicked cell.
    public void dataGridView1_CellValueChanged(object sender,
        DataGridViewCellEventArgs e)
    {
        if (dataGridView1.Columns[e.ColumnIndex].Name == "CheckBoxes")
        {
            DataGridViewDisableButtonCell buttonCell =
                (DataGridViewDisableButtonCell)dataGridView1.
                Rows[e.RowIndex].Cells["Buttons"];

            DataGridViewCheckBoxCell checkCell =
                (DataGridViewCheckBoxCell)dataGridView1.
                Rows[e.RowIndex].Cells["CheckBoxes"];
            buttonCell.Enabled = !(Boolean)checkCell.Value;

            dataGridView1.Invalidate();
        }
    }

    // If the user clicks on an enabled button cell, this event handler  
    // reports that the button is enabled.
    void dataGridView1_CellClick(object sender,
        DataGridViewCellEventArgs e)
    {
        if (dataGridView1.Columns[e.ColumnIndex].Name == "Buttons")
        {
            DataGridViewDisableButtonCell buttonCell =
                (DataGridViewDisableButtonCell)dataGridView1.
                Rows[e.RowIndex].Cells["Buttons"];

            if (buttonCell.Enabled)
            {
                MessageBox.Show(dataGridView1.Rows[e.RowIndex].
                    Cells[e.ColumnIndex].Value.ToString() +
                    " is enabled");
            }
        }
    }
}

public class DataGridViewDisableButtonColumn : DataGridViewButtonColumn
{
    public DataGridViewDisableButtonColumn()
    {
        this.CellTemplate = new DataGridViewDisableButtonCell();
    }
}

public class DataGridViewDisableButtonCell : DataGridViewButtonCell
{
    private bool enabledValue;
    public bool Enabled
    {
        get
        {
            return enabledValue;
        }
        set
        {
            enabledValue = value;
        }
    }

    // Override the Clone method so that the Enabled property is copied.
    public override object Clone()
    {
        DataGridViewDisableButtonCell cell =
            (DataGridViewDisableButtonCell)base.Clone();
        cell.Enabled = this.Enabled;
        return cell;
    }

    // By default, enable the button cell.
    public DataGridViewDisableButtonCell()
    {
        this.enabledValue = true;
    }

    protected override void Paint(Graphics graphics,
        Rectangle clipBounds, Rectangle cellBounds, int rowIndex,
        DataGridViewElementStates elementState, object value,
        object formattedValue, string errorText,
        DataGridViewCellStyle cellStyle,
        DataGridViewAdvancedBorderStyle advancedBorderStyle,
        DataGridViewPaintParts paintParts)
    {
        // The button cell is disabled, so paint the border,  
        // background, and disabled button for the cell.
        if (!this.enabledValue)
        {
            // Draw the cell background, if specified.
            if ((paintParts & DataGridViewPaintParts.Background) ==
                DataGridViewPaintParts.Background)
            {
                SolidBrush cellBackground =
                    new SolidBrush(cellStyle.BackColor);
                graphics.FillRectangle(cellBackground, cellBounds);
                cellBackground.Dispose();
            }

            // Draw the cell borders, if specified.
            if ((paintParts & DataGridViewPaintParts.Border) ==
                DataGridViewPaintParts.Border)
            {
                PaintBorder(graphics, clipBounds, cellBounds, cellStyle,
                    advancedBorderStyle);
            }

            // Calculate the area in which to draw the button.
            Rectangle buttonArea = cellBounds;
            Rectangle buttonAdjustment =
                this.BorderWidths(advancedBorderStyle);
            buttonArea.X += buttonAdjustment.X;
            buttonArea.Y += buttonAdjustment.Y;
            buttonArea.Height -= buttonAdjustment.Height;
            buttonArea.Width -= buttonAdjustment.Width;

            // Draw the disabled button.                
            ButtonRenderer.DrawButton(graphics, buttonArea,
                PushButtonState.Disabled);

            // Draw the disabled button text. 
            if (this.FormattedValue is String) 
            {
                TextRenderer.DrawText(graphics,
                    (string)this.FormattedValue,
                    this.DataGridView.Font,
                    buttonArea, SystemColors.GrayText);
            }
        }
        else
        {
            // The button cell is enabled, so let the base class 
            // handle the painting.
            base.Paint(graphics, clipBounds, cellBounds, rowIndex,
                elementState, value, formattedValue, errorText,
                cellStyle, advancedBorderStyle, paintParts);
        }
    }
}