Como hospedar controles em células DataGridView dos Windows Forms

O DataGridView controle fornece vários tipos de coluna, permitindo que os usuários insiram e editem valores de várias maneiras. No entanto, se esses tipos de coluna não atenderem às suas necessidades de entrada de dados, será possível criar seus próprios tipos de coluna com células que hospedam controles de sua escolha. Para fazer isso, você deve definir classes que derivam de DataGridViewColumn e DataGridViewCell. Você também deve definir uma classe que deriva e Control implementa a IDataGridViewEditingControl interface.

O exemplo de código a seguir mostra como criar uma coluna de calendário. As células desta coluna exibem datas em células comuns da caixa de texto, mas quando o usuário edita uma célula, um DateTimePicker controle é exibido. Para evitar ter que implementar a funcionalidade de exibição de caixa de texto novamente, a classe deriva da classe em vez de DataGridViewTextBoxCell herdar a CalendarCellDataGridViewCell classe diretamente.

Exemplo

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;
        // 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()
    {
        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);
    }
}

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;
        }
    }
}

Imports System.Windows.Forms

Public Class CalendarColumn
    Inherits DataGridViewColumn

    Public Sub New()
        MyBase.New(New CalendarCell())
    End Sub

    Public Overrides Property CellTemplate() As DataGridViewCell
        Get
            Return MyBase.CellTemplate
        End Get
        Set(ByVal value As DataGridViewCell)

            ' Ensure that the cell used for the template is a CalendarCell.
            If (value IsNot Nothing) AndAlso _
                Not value.GetType().IsAssignableFrom(GetType(CalendarCell)) _
                Then
                Throw New InvalidCastException("Must be a CalendarCell")
            End If
            MyBase.CellTemplate = value

        End Set
    End Property

End Class

Public Class CalendarCell
    Inherits DataGridViewTextBoxCell

    Public Sub New()
        ' Use the short date format.
        Me.Style.Format = "d"
    End Sub

    Public Overrides Sub InitializeEditingControl(ByVal rowIndex As Integer, _
        ByVal initialFormattedValue As Object, _
        ByVal dataGridViewCellStyle As DataGridViewCellStyle)

        ' Set the value of the editing control to the current cell value.
        MyBase.InitializeEditingControl(rowIndex, initialFormattedValue, _
            dataGridViewCellStyle)

        Dim ctl As CalendarEditingControl = _
            CType(DataGridView.EditingControl, CalendarEditingControl)

        ' Use the default row value when Value property is null.
        If (Me.Value Is Nothing) Then
            ctl.Value = CType(Me.DefaultNewRowValue, DateTime)
        Else
            ctl.Value = CType(Me.Value, DateTime)
        End If
    End Sub

    Public Overrides ReadOnly Property EditType() As Type
        Get
            ' Return the type of the editing control that CalendarCell uses.
            Return GetType(CalendarEditingControl)
        End Get
    End Property

    Public Overrides ReadOnly Property ValueType() As Type
        Get
            ' Return the type of the value that CalendarCell contains.
            Return GetType(DateTime)
        End Get
    End Property

    Public Overrides ReadOnly Property DefaultNewRowValue() As Object
        Get
            ' Use the current date and time as the default value.
            Return DateTime.Now
        End Get
    End Property

End Class

Class CalendarEditingControl
    Inherits DateTimePicker
    Implements IDataGridViewEditingControl

    Private dataGridViewControl As DataGridView
    Private valueIsChanged As Boolean = False
    Private rowIndexNum As Integer

    Public Sub New()
        Me.Format = DateTimePickerFormat.Short
    End Sub

    Public Property EditingControlFormattedValue() As Object _
        Implements IDataGridViewEditingControl.EditingControlFormattedValue

        Get
            Return Me.Value.ToShortDateString()
        End Get

        Set(ByVal value As Object)
            Try
                ' This will throw an exception of the string is 
                ' null, empty, or not in the format of a date.
                Me.Value = DateTime.Parse(CStr(value))
            Catch
                ' In the case of an exception, just use the default
                ' value so we're not left with a null value.
                Me.Value = DateTime.Now
            End Try
        End Set

    End Property

    Public Function GetEditingControlFormattedValue(ByVal context _
        As DataGridViewDataErrorContexts) As Object _
        Implements IDataGridViewEditingControl.GetEditingControlFormattedValue

        Return Me.Value.ToShortDateString()

    End Function

    Public Sub ApplyCellStyleToEditingControl(ByVal dataGridViewCellStyle As _
        DataGridViewCellStyle) _
        Implements IDataGridViewEditingControl.ApplyCellStyleToEditingControl

        Me.Font = dataGridViewCellStyle.Font
        Me.CalendarForeColor = dataGridViewCellStyle.ForeColor
        Me.CalendarMonthBackground = dataGridViewCellStyle.BackColor

    End Sub

    Public Property EditingControlRowIndex() As Integer _
        Implements IDataGridViewEditingControl.EditingControlRowIndex

        Get
            Return rowIndexNum
        End Get
        Set(ByVal value As Integer)
            rowIndexNum = value
        End Set

    End Property

    Public Function EditingControlWantsInputKey(ByVal key As Keys, _
        ByVal dataGridViewWantsInputKey As Boolean) As Boolean _
        Implements IDataGridViewEditingControl.EditingControlWantsInputKey

        ' Let the DateTimePicker handle the keys listed.
        Select Case key And Keys.KeyCode
            Case Keys.Left, Keys.Up, Keys.Down, Keys.Right, _
                Keys.Home, Keys.End, Keys.PageDown, Keys.PageUp

                Return True

            Case Else
                Return Not dataGridViewWantsInputKey
        End Select

    End Function

    Public Sub PrepareEditingControlForEdit(ByVal selectAll As Boolean) _
        Implements IDataGridViewEditingControl.PrepareEditingControlForEdit

        ' No preparation needs to be done.

    End Sub

    Public ReadOnly Property RepositionEditingControlOnValueChange() _
        As Boolean Implements _
        IDataGridViewEditingControl.RepositionEditingControlOnValueChange

        Get
            Return False
        End Get

    End Property

    Public Property EditingControlDataGridView() As DataGridView _
        Implements IDataGridViewEditingControl.EditingControlDataGridView

        Get
            Return dataGridViewControl
        End Get
        Set(ByVal value As DataGridView)
            dataGridViewControl = value
        End Set

    End Property

    Public Property EditingControlValueChanged() As Boolean _
        Implements IDataGridViewEditingControl.EditingControlValueChanged

        Get
            Return valueIsChanged
        End Get
        Set(ByVal value As Boolean)
            valueIsChanged = value
        End Set

    End Property

    Public ReadOnly Property EditingControlCursor() As Cursor _
        Implements IDataGridViewEditingControl.EditingPanelCursor

        Get
            Return MyBase.Cursor
        End Get

    End Property

    Protected Overrides Sub OnValueChanged(ByVal eventargs As EventArgs)

        ' Notify the DataGridView that the contents of the cell have changed.
        valueIsChanged = True
        Me.EditingControlDataGridView.NotifyCurrentCellDirty(True)
        MyBase.OnValueChanged(eventargs)

    End Sub

End Class

Public Class Form1
    Inherits Form

    Private dataGridView1 As New DataGridView()

    <STAThreadAttribute()> _
    Public Shared Sub Main()
        Application.Run(New Form1())
    End Sub

    Public Sub New()
        Me.dataGridView1.Dock = DockStyle.Fill
        Me.Controls.Add(Me.dataGridView1)
        Me.Text = "DataGridView calendar column demo"
    End Sub

    Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs) _
        Handles Me.Load

        Dim col As New CalendarColumn()
        Me.dataGridView1.Columns.Add(col)
        Me.dataGridView1.RowCount = 5
        Dim row As DataGridViewRow
        For Each row In Me.dataGridView1.Rows
            row.Cells(0).Value = DateTime.Now
        Next row

    End Sub

End Class

Compilando o código

O exemplo a seguir requer:

• Referências aos assemblies Sistema e System.Windows.Forms.

Confira também

• DataGridView
• DataGridViewColumn
• DataGridViewCell
• DataGridViewTextBoxCell
• IDataGridViewEditingControl
• DateTimePicker
• Personalizando o controle DataGridView dos Windows Forms
• Arquitetura de controle DataGridView
• Tipos de coluna no controle DataGridView dos Windows Forms