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。
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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。 |
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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; } } }