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Spread Windows Forms 13.0 Product Documentation / Developer's Guide / Customizing Interaction with Cell Types / Understanding Additional Features of Cell Types / Creating a Custom Cell Type
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    Creating a Custom Cell Type
    In This Topic

    You can implement your own types of cells by creating a subclass that inherits an existing cell type (that is, overriding each method in that class). The custom cell type class should be marked as serializable if the Clipboard will be used with it or if the export to Excel methods are used.

    For information on other features of cell types, refer to Understanding Additional Features of Cell Types.

    Using Code

    This example subclasses the check box cell type to illustrate the use of the methods.

    C#
    Copy Code
    class myCkBox : FarPoint.Win.Spread.CellType.CheckBoxCellType
    {
    CheckBox ckbx = new CheckBox();

    public myCkBox()
    {
    }
    new event EventHandler EditingCanceled;
    new event EventHandler EditingStopped;

    public override void StartEditing(EventArgs e, bool selectAll, bool autoClipboard)
    {
       return;
    }
    public override void CancelEditing()
    {
       EditingCanceled(ckbx, EventArgs.Empty);
       base.FireEditingCanceled();
    }
    public override bool StopEditing()
    {
       if (EditingStopped != null)
       {
          EditingStopped(ckbx, EventArgs.Empty);
          base.FireEditingStopped();
          return true;
       }
       else
       {
          return false;
       }
    }

    public override bool IsReservedKey(KeyEventArgs e)
    {
       return base.IsReservedKey(e);
    }
    public override object IsReservedLocation(Graphics g, int x, int y, Rectangle r, FarPoint.Win.Spread.Appearance appr, object
    value, float zoom)
    {
       return base.IsReservedLocation(g, x, y, r, appr, value, zoom);
    }
    public override Size GetPreferredSize(Graphics g, Size size, FarPoint.Win.Spread.Appearance appr, object value, float zoom)
    {
       return base.GetPreferredSize(g, size, appr, value, zoom);
    }
    public override object Parse(string s)
    {
       return base.Parse(s);
    }
    public override string Format(object o)
    {
       return base.Format(o.ToString());
    }
    public override Control GetEditorControl(FarPoint.Win.Spread.Appearance appearance, float zoomFactor)
    {
       return ckbx;
    }
    public override object GetEditorValue()
    {
       return ckbx.CheckState;
    }
    public override void PaintCell(Graphics g, Rectangle r, FarPoint.Win.Spread.Appearance appr, object value, bool issel, bool
    islocked, float zoom)
    {
       GetEditorValue();
       if (ckbx.CheckState == CheckState.Checked)
       {
          ControlPaint.DrawCheckBox(g, r.X, r.Y, r.Width - 40, r.Height - 6, ButtonState.Checked);
       }
       else if (ckbx.CheckState == CheckState.Unchecked)
       {
         ControlPaint.DrawCheckBox(g, r.X, r.Y, r.Width - 40, r.Height - 6, ButtonState.Normal);
       }
    }
    public override void SetEditorValue(object value)
    {
       ckbx.CheckState = CheckState.Checked;
    }
    public override Cursor GetReservedCursor(object o)
    {
       return base.GetReservedCursor(o);
    }
    }

    private void menuItem4_Click(object sender, System.EventArgs e)
    {
       myCkBox ckbx = new myCkBox();
       fpSpread1.ActiveSheet.Cells[0, 0].CellType = ckbx;
    }
    VB
    Copy Code
    Public Class myCkBox
    Inherits FarPoint.Win.Spread.CellType.CheckBoxCellType

    Dim ckbx As New CheckBox()

    Sub New()

    End Sub

    Public Shadows Event EditingStopped(ByVal sender As Object, ByVal e As EventArgs)

    Public Shadows Event EditingCancelled(ByVal sender As Object, ByVal e As EventArgs)

    Public Overrides Sub StartEditing(ByVal e As EventArgs, ByVal selectAll As Boolean, ByVal autoClipboard As Boolean)
       MyBase.StartEditing(e, selectAll, autoClipboard)
    End Sub

    Public Overrides Sub CancelEditing()
       RaiseEvent EditingCancelled(ckbx, EventArgs.Empty)
       MyBase.FireEditingCanceled()
    End Sub

    Public Overrides Function StopEditing() As Boolean
       RaiseEvent EditingStopped(ckbx, EventArgs.Empty)
       MyBase.FireEditingStopped()
       Return True
    End Function

    Public Overrides Function IsReservedKey(ByVal e As KeyEventArgs) As Boolean
       Return MyBase.IsReservedKey(e)
    End Function

    Public Overrides Function IsReservedLocation(ByVal g As Graphics, ByVal x As Integer, ByVal y As Integer, ByVal r As Rectangle,
    ByVal appr As FarPoint.Win.Spread.Appearance, ByVal value As Object, ByVal zoom As Single) As Object
       Return MyBase.IsReservedLocation(g, x, y, r, appr, value, zoom)
    End Function

    Public Overrides Function GetPreferredSize(ByVal g As Graphics, ByVal s As Size, ByVal appr As FarPoint.Win.Spread.Appearance,
    ByVal value As Object, ByVal zoom As Single) As Size
       Return MyBase.GetPreferredSize(g, s, appr, value, zoom)
    End Function

    Public Overrides Function Parse(ByVal s As String) As Object
       Return MyBase.Parse(s)
    End Function

    Public Overrides Function Format(ByVal o As Object) As String
       Return MyBase.Format(o)
    End Function

    Public Overrides Function GetEditorControl(ByVal appr As FarPoint.Win.Spread.Appearance, ByVal zoom As Single) As Control
       Return ckbx
    End Function

    Public Overrides Function GetEditorValue() As Object
       Return ckbx.CheckState
    End Function

    Public Overrides Sub PaintCell(ByVal g As Graphics, ByVal r As Rectangle, ByVal appr As FarPoint.Win.Spread.Appearance, ByVal
    Value As Object, ByVal issel As Boolean, ByVal islocked As Boolean, ByVal zoom As Single)
       GetEditorValue()
       If ckbx.CheckState = CheckState.Checked Then
          ControlPaint.DrawCheckBox(g, r.X, r.Y, r.Width - 40, r.Height - 6, ButtonState.Checked)
       ElseIf ckbx.CheckState = CheckState.Unchecked Then
          ControlPaint.DrawCheckBox(g, r.X, r.Y, r.Width - 40, r.Height - 6, ButtonState.Normal)
       End If
    End Sub

    Public Overrides Sub SetEditorValue(ByVal value As Object)
       ckbx.CheckState = CheckState.Checked
    End Sub

    Public Overrides Function GetReservedCursor(ByVal o As Object) As Cursor
       Return MyBase.GetReservedCursor(o)
    End Function
    End Class

    Private Sub MenuItem1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MenuItem1.Click
       Dim ckbx As New myCkBox()
       fpSpread1.ActiveSheet.Cells(0, 0).CellType = ckbx
    End Sub
    See Also