DataGridView自定义列在运行时访问设计时参数
本文关键字:参数 访问 运行时 自定义 DataGridView | 更新日期: 2023-09-27 18:23:35
我一直在玩一些示例代码,它实现了DataGridView的日期选择器列。
我遇到的困难是如何在CalendarEditingControl中适当地访问设计时参数(感谢Bradley Smith提供的关于覆盖克隆方法的提示),我想在这里将Format设置为DateFormat。
我已经在下面提供了完整的示例,如果你只是扫描评论,我想看看在哪里使用DateFormat://***********.strong>我想将格式设置为DataGridViewCalendarColumn.DateFormat中提供的设计时间值****.******/em>***
感谢
马特
使用系统;使用System.Windows.Forms;
命名空间MyApplication.Components{公共类DataGridViewCalendarColumn:DataGridViewColumn{公共DataGridViewCalendarColumn():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 DateTimePickerFormat DateFormat { get; set; }
public override object Clone()
{
DataGridViewCalendarColumn clone = (DataGridViewCalendarColumn)base.Clone();
clone.DateFormat = this.DateFormat;
return clone;
}
}
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;
// Use the default row value when Value property is null.
if (this.Value == null)
{
ctl.Value = (DateTime)this.DefaultNewRowValue;
}
else
{
ctl.Value = (DateTime)this.Value;
}
}
public override Type EditType
{
get
{
// Return the type of the editing control 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()
{
//*********************** I'd like to set the Format to the design time value provided inDataGridViewCalendarColumn.DateFormat here ***********************//
//(instead of hard coding it to DateTimePickerFormat.Short)
this.Format = DateTimePickerFormat.Short;
}
// Implements the IDataGridViewEditingControl.EditingControlFormattedValue
// property.
public object EditingControlFormattedValue
{
get
{
return this.Value.ToShortDateString();
}
set
{
if (value is String)
{
try
{
// This will throw an exception of the string is
// null, empty, or not in the format of a date.
this.Value = DateTime.Parse((String)value);
}
catch
{
// In the case of an exception, just use the
// default value so we're not left with a null
// value.
this.Value = DateTime.Now;
}
}
}
}
// 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);
}
}
}
您所需要做的就是将列中的DateFormat
属性应用到编辑控件上。在InitializeEditingControl
方法中,添加以下行:
ctl.Format = (OwningColumn as DataGridViewCalendarColumn).DateFormat;
这就行了。
在WinForms(以及WebForms和WPF…)中,您无法访问构造函数中的设计时值。相反,框架调用无参数构造函数,然后在对象上使用适当的属性设置器来完成初始化
在构造函数中为对象的属性设置默认值是一件明智的事情,以防设计器用户在设计时没有指定所有属性值应该是什么。因此,您的构造函数是好的。