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Het besturingselement DataGridView bevat de DataGridViewButtonCell klasse voor het weergeven van cellen met een gebruikersinterface (UI) zoals een knop. DataGridViewButtonCell biedt echter geen manier om het uiterlijk van de knop uit te schakelen die door de cel wordt weergegeven.
In het volgende codevoorbeeld ziet u hoe u de DataGridViewButtonCell klasse aanpast om knoppen weer te geven die kunnen worden uitgeschakeld. In het voorbeeld wordt een nieuw celtype, DataGridViewDisableButtonCell, gedefinieerd dat is afgeleid van DataGridViewButtonCell. Dit celtype bevat een nieuwe Enabled eigenschap die kan worden ingesteld op false om een uitgeschakelde knop in de cel te tekenen. In het voorbeeld wordt ook een nieuw kolomtype gedefinieerd, DataGridViewDisableButtonColumn, waarin DataGridViewDisableButtonCell objecten worden weergegeven. Om dit nieuwe cel- en kolomtype te demonstreren, bepaalt de actuele waarde van elke DataGridViewCheckBoxCell in het bovenliggende DataGridView of de Enabled-eigenschap van de DataGridViewDisableButtonCell in dezelfde rij true of falseis.
Opmerking
Wanneer u bent afgeleid van DataGridViewCell of DataGridViewColumn en nieuwe eigenschappen toevoegt aan de afgeleide klasse, moet u de methode Clone overschrijven om de nieuwe eigenschappen te kopiëren tijdens het klonen. U moet ook de Clone methode van de basisklasse aanroepen, zodat de eigenschappen van de basisklasse worden gekopieerd naar de nieuwe cel of kolom.
Voorbeeld
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);
}
}
}
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
De code compileren
Voor dit voorbeeld is het volgende vereist:
- Verwijzingen naar de assembly's System, System.Drawing, System.Windows.Forms en System.Windows.Forms.VisualStyles.
Zie ook
Met ons samenwerken op GitHub
De bron voor deze inhoud vindt u op GitHub, waar u ook problemen en pull-aanvragen kunt maken en controleren. Bekijk onze gids voor inzenders voor meer informatie.
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