在 Windows 窗体 DataGridView 单元格中承载控件

DataGridView 控件提供了多种列类型，使得用户可以通过多种方式输入和编辑值。但是，如果这些列类型无法满足数据输入要求，您也可以使用承载所选控件的单元格创建自己的列类型。要做到这一点，必须定义派生自DataGridViewColumn 和 DataGridViewCell 的类。您还必须定义派生自 Control 并实现IDataGridViewEditingControl 接口的类。

下面的代码示例演示如何创建日历列。此列的单元格在普通的文本框单元格中显示日期，但当用户编辑单元格时，就会出现 DateTimePicker 控件。为了避免必须再次实现文本框显示功能，CalendarCell 类从DataGridViewTextBoxCell 类派生，而不是直接从 DataGridViewCell 类继承。

说明：
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。

示例C#

using System;
using System.Windows.Forms;

public class CalendarColumn : DataGridViewColumn
{
public CalendarColumn() : base(new CalendarCell())
{
}

public override DataGridViewCell CellTemplate
{
get
{
return base.CellTemplate;
}
set
{
// Ensure that the cell used for the template is a CalendarCell.
if (value != null &&
!value.GetType().IsAssignableFrom(typeof(CalendarCell)))
{
throw new InvalidCastException("Must be a CalendarCell");
}
base.CellTemplate = value;
}
}
}

public class CalendarCell : DataGridViewTextBoxCell
{

public CalendarCell()
: base()
{
// Use the short date format.
this.Style.Format = "d";
}

public override void InitializeEditingControl(int rowIndex, object
initialFormattedValue, DataGridViewCellStyle dataGridViewCellStyle)
{
// Set the value of the editing control to the current cell value.
base.InitializeEditingControl(rowIndex, initialFormattedValue,
dataGridViewCellStyle);
CalendarEditingControl ctl =
DataGridView.EditingControl as CalendarEditingControl;
ctl.Value = (DateTime)this.Value;
}

public override Type EditType
{
get
{
// Return the type of the editing contol that CalendarCell uses.
return typeof(CalendarEditingControl);
}
}

public override Type ValueType
{
get
{
// Return the type of the value that CalendarCell contains.
return typeof(DateTime);
}
}

public override object DefaultNewRowValue
{
get
{
// Use the current date and time as the default value.
return DateTime.Now;
}
}
}

class CalendarEditingControl : DateTimePicker, IDataGridViewEditingControl
{
DataGridView dataGridView;
private bool valueChanged = false;
int rowIndex;

public CalendarEditingControl()
{
this.Format = DateTimePickerFormat.Short;
}

// Implements the IDataGridViewEditingControl.EditingControlFormattedValue
// property.
public object EditingControlFormattedValue
{
get
{
return this.Value.ToShortDateString();
}
set
{
if (value is String)
{
this.Value = DateTime.Parse((String)value);
}
}
}

// Implements the
// IDataGridViewEditingControl.GetEditingControlFormattedValue method.
public object GetEditingControlFormattedValue(
DataGridViewDataErrorContexts context)
{
return EditingControlFormattedValue;
}

// Implements the
// IDataGridViewEditingControl.ApplyCellStyleToEditingControl method.
public void ApplyCellStyleToEditingControl(
DataGridViewCellStyle dataGridViewCellStyle)
{
this.Font = dataGridViewCellStyle.Font;
this.CalendarForeColor = dataGridViewCellStyle.ForeColor;
this.CalendarMonthBackground = dataGridViewCellStyle.BackColor;
}

// Implements the IDataGridViewEditingControl.EditingControlRowIndex
// property.
public int EditingControlRowIndex
{
get
{
return rowIndex;
}
set
{
rowIndex = value;
}
}

// Implements the IDataGridViewEditingControl.EditingControlWantsInputKey
// method.
public bool EditingControlWantsInputKey(
Keys key, bool dataGridViewWantsInputKey)
{
// Let the DateTimePicker handle the keys listed.
switch (key & Keys.KeyCode)
{
case Keys.Left:
case Keys.Up:
case Keys.Down:
case Keys.Right:
case Keys.Home:
case Keys.End:
case Keys.PageDown:
case Keys.PageUp:
return true;
default:
return !dataGridViewWantsInputKey;
}
}

// Implements the IDataGridViewEditingControl.PrepareEditingControlForEdit
// method.
public void PrepareEditingControlForEdit(bool selectAll)
{
// No preparation needs to be done.
}

// Implements the IDataGridViewEditingControl
// .RepositionEditingControlOnValueChange property.
public bool RepositionEditingControlOnValueChange
{
get
{
return false;
}
}

// Implements the IDataGridViewEditingControl
// .EditingControlDataGridView property.
public DataGridView EditingControlDataGridView
{
get
{
return dataGridView;
}
set
{
dataGridView = value;
}
}

// Implements the IDataGridViewEditingControl
// .EditingControlValueChanged property.
public bool EditingControlValueChanged
{
get
{
return valueChanged;
}
set
{
valueChanged = value;
}
}

// Implements the IDataGridViewEditingControl
// .EditingPanelCursor property.
public Cursor EditingPanelCursor
{
get
{
return base.Cursor;
}
}

protected override void OnValueChanged(EventArgs eventargs)
{
// Notify the DataGridView that the contents of the cell
// have changed.
valueChanged = true;
this.EditingControlDataGridView.NotifyCurrentCellDirty(true);
base.OnValueChanged(eventargs);
}
}

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

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

public Form1()
{
this.dataGridView1.Dock = DockStyle.Fill;
this.Controls.Add(this.dataGridView1);
this.Load += new EventHandler(Form1_Load);
this.Text = "DataGridView calendar column demo";
}

private void Form1_Load(object sender, EventArgs e)
{
CalendarColumn col = new CalendarColumn();
this.dataGridView1.Columns.Add(col);
this.dataGridView1.RowCount = 5;
foreach (DataGridViewRow row in this.dataGridView1.Rows)
{
row.Cells[0].Value = DateTime.Now;
}
}
}