WinForm下DataGridView单选按钮列和支持三种选择状态的复选框列的实现
在C# WinForm下做过项目的朋友都知道,其中的DataGridView控件默认只支持DataGridViewButtonColumn、DataGridViewCheckBoxColumn、DataGridViewComboBoxColumn、DataGridViewImageColumn、DataGridViewLinkColumn和DataGridViewTextBoxColumn六种列类型,如果你想要在DataGridView的列中添加其它的子控件,则需要自己实现DataGridViewColumn和DataGridViewCell,这就意味着你需要从现有的列中继承并改写一些方法,如实现一个支持单选按钮的列,或支持三种选择状态的多选按钮的列。 下面两个截图分别为RadioButton列和支持三种状态的CheckBox列在DataGridView中的实现效果,我是在Windows 2003中实现的,因此显示的效果跟在XP和Vista下有些区别,Vista下CheckBox的第三种状态(不确定状态)显示出来的效果是一个实心的蓝色方块。 下面我看具体来看看如何实现这两种效果。 要实现自定义的DataGridView列,你需要继承并改写两个类,一个是基于DataGridViewColumn的,一个是基于DataGridViewCell的,因为RadionButton和CheckBox的实现原理类似,因此我们可以将这两种列采用同一种方法实现。创建DataGridViewDisableCheckBoxCell和DataGridViewDisableCheckBoxColumn两个类,分别继承自DataGridViewCheckBoxCell和DataGridViewCheckBoxColumn。代码如下: public class DataGridViewDisableCheckBoxCell: DataGridViewCheckBoxCell{ public bool Enabled { get; set; } // 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; } // By default, enable the CheckBox cell. public DataGridViewDisableCheckBoxCell() { this.Enabled = true; } // Three state checkbox column cell 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 checkBox cell is disabled, so paint the border, background, and disabled checkBox for the cell. if (!this.Enabled) { // 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 checkBox. CheckBoxState state = CheckBoxState.MixedDisabled; Size size = CheckBoxRenderer.GetGlyphSize(graphics, state); Point center = new Point(cellBounds.X, cellBounds.Y); center.X += (cellBounds.Width - size.Width) / 2; center.Y += (cellBounds.Height - size.Height) / 2; // Draw the disabled checkBox. CheckBoxRenderer.DrawCheckBox(graphics, center, state); } else { // The checkBox cell is enabled, so let the base class, handle the painting. base.Paint(graphics, clipBounds, cellBounds, rowIndex, elementState, value, formattedValue, errorText, cellStyle, advancedBorderStyle, paintParts); } } } |
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