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;

        }

    }

}