实现Datagridview里checkbox的enabled效果
我们都知道，Datagridview控件里的checkbox是没有enabled事件的，但实际应用中我们有时会需要实现这种效果。怎么办呢？思想很简单，继承控件。vb.net:
Public Class DataGridViewDisableCheckBoxColumn Inherits DataGridViewCheckBoxColumn Sub New() Me.CellTemplate = New DataGridViewDisableCheckBoxCell() End SubEnd ClassPublic Class DataGridViewDisableCheckBoxCell Inherits DataGridViewCheckBoxCell Dim enabledValue As Boolean Public Property Enabled() As Boolean Get Return enabledValue End Get Set(ByVal value As Boolean) enabledValue = value End Set End Property Public Overrides Function Clone() As Object Dim cell As New DataGridViewDisableCheckBoxCell cell = MyBase.Clone Return cell End Function Protected Overrides Sub Paint(ByVal graphics As System.Drawing.Graphics, ByVal clipBounds As System.Drawing.Rectangle, ByVal cellBounds As System.Drawing.Rectangle, ByVal rowIndex As Integer, ByVal elementState As System.Windows.Forms.DataGridViewElementStates, ByVal value As Object, ByVal formattedValue As Object, ByVal errorText As String, ByVal cellStyle As System.Windows.Forms.DataGridViewCellStyle, ByVal advancedBorderStyle As System.Windows.Forms.DataGridViewAdvancedBorderStyle, ByVal paintParts As System.Windows.Forms.DataGridViewPaintParts) MyBase.Paint(graphics, clipBounds, cellBounds, rowIndex, elementState, value, formattedValue, errorText, cellStyle, advancedBorderStyle, paintParts) If (Me.enabledValue) Then Dim cellBackground As New SolidBrush(cellStyle.BackColor) graphics.FillRectangle(cellBackground, cellBounds) cellBackground.Dispose() PaintBorder(graphics, clipBounds, cellBounds, cellStyle, advancedBorderStyle) Dim checkBoxArea As Rectangle = cellBounds Dim buttonAdjustment As Rectangle = Me.BorderWidths(advancedBorderStyle) checkBoxArea.X += buttonAdjustment.X checkBoxArea.Y += buttonAdjustment.Y checkBoxArea.Height -= buttonAdjustment.Height checkBoxArea.Width -= buttonAdjustment.Width Dim drawInPoint As New Point(cellBounds.X + cellBounds.Width / 2 - 7, cellBounds.Y + cellBounds.Height / 2 - 7) CheckBoxRenderer.DrawCheckBox(graphics, drawInPoint, System.Windows.Forms.VisualStyles.CheckBoxState.CheckedDisabled) End If End SubEnd Class
c#:
public class DataGridViewDisableCheckBoxColumn : DataGridViewCheckBoxColumn { public DataGridViewDisableCheckBoxColumn() { this.CellTemplate = new DataGridViewDisableCheckBoxCell(); } } public class DataGridViewDisableCheckBoxCell : DataGridViewCheckBoxCell { private bool enabledValue; /// <summary> /// This property decides whether the checkbox should be shown checked or unchecked. /// </summary> public bool Enabled { get { return enabledValue; } set { enabledValue = value; } } /// Override the Clone method so that the Enabled property is copied. public override object Clone() { DataGridViewDisableCheckBoxCell cell = (DataGridViewDisableCheckBoxCell)base.Clone(); cell.Enabled = this.Enabled; return cell; } public DataGridViewDisableCheckBoxCell() { } /// <summary> /// Override the Paint method to show the disabled checked/unchecked datagridviewcheckboxcell. /// </summary> 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) { base.Paint(graphics, clipBounds, cellBounds, rowIndex, elementState, value, formattedValue, errorText, cellStyle, advancedBorderStyle, paintParts); if (this.enabledValue) { SolidBrush cellBackground = new SolidBrush(cellStyle.BackColor); graphics.FillRectangle(cellBackground, cellBounds); cellBackground.Dispose(); PaintBorder(graphics, clipBounds, cellBounds, cellStyle, advancedBorderStyle); Rectangle checkBoxArea = cellBounds; Rectangle buttonAdjustment = this.BorderWidths(advancedBorderStyle); checkBoxArea.X += buttonAdjustment.X; checkBoxArea.Y += buttonAdjustment.Y; checkBoxArea.Height -= buttonAdjustment.Height; checkBoxArea.Width -= buttonAdjustment.Width; Point drawInPoint = new Point(cellBounds.X + cellBounds.Width / 2 - 7, cellBounds.Y + cellBounds.Height / 2 - 7); CheckBoxRenderer.DrawCheckBox(graphics, drawInPoint, System.Windows.Forms.VisualStyles.CheckBoxState.CheckedDisabled); } } }
使用方法很简单，将datagridview里的checkbox控件定义为DataGridViewDisableCheckBoxColumn型，将其enabled属性设置为true,就会看到效果。需要注意的地方是，虽然看起来控件是灰色，并且鼠标点击的时候checkbox选中状态不会改变，但是，该控件的value值还是改变了，如果你不想点击的时候改变其value值，那么再设置控件的Readonly=False。
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