Custom DataGridCellElement drawing its content into neighboring cell

[Christoph]

Hi,
I am trying to implement a custom DataGridCellElement that contains a label and a hyperlink. For both elements I use RadLabelElements with different font styles. 
My problem is, that if the cell is too small to hold the whole text of both elements the text of the hyperlink is drawn into the neighboring cell on the right. What is wrong with my code?
(Q1 2011 SP1, .NET 3.5)

Thanks in advance, Christoph

public class HyperlinkCellElement : GridDataCellElement
{
    private RadLabelElement _headerLabel;
    private RadLabelElement _linkLabel;

    public HyperlinkCellElement(GridViewColumn column, GridRowElement row) : base(column, row) {}

    protected override Type ThemeEffectiveType { get {return typeof(GridDataCellElement); } }

    public override void Initialize(GridViewColumn column, GridRowElement row)
    {
        base.Initialize(column, row);
        _headerLabel.Text = column.Name;
    }

    protected override void CreateChildElements()
    {
        _headerLabel = new RadLabelElement();
        _headerLabel.Font = new Font(Font, FontStyle.Bold);
        _headerLabel.Margin = new Padding(0, 2, 0, 0);
        _headerLabel.LabelText.AutoEllipsis = true;
        _headerLabel.LabelText.AutoSize = true;
        _headerLabel.LabelText.AutoSizeMode = RadAutoSizeMode.Auto;
        _headerLabel.LabelText.TextWrap = false;

        _linkLabel = new RadLabelElement();
        _linkLabel.Font = new Font(Font, FontStyle.Underline);
        _linkLabel.MouseHover += (s, e) =>
             { if (Cursor.Current == Cursors.Default) Cursor.Current = Cursors.Hand; };
        _linkLabel.MouseLeave += (s, e) =>
             { if (Cursor.Current == Cursors.Hand) Cursor.Current = Cursors.Default; };
        _linkLabel.Margin = new Padding(0, 2, 0, 0);
        _linkLabel.LabelText.AutoEllipsis = true;
        _linkLabel.LabelText.AutoSize = true;
        _linkLabel.LabelText.AutoSizeMode = RadAutoSizeMode.Auto;
        _linkLabel.LabelText.TextWrap = false;

        this.Children.Add(_headerLabel);
        this.Children.Add(_linkLabel);

        _linkLabel.Click += new EventHandler(_label_Click);
    }

    void _label_Click(object sender, EventArgs e)
    {
        //TODO;
    }

    protected override void DisposeManagedResources()
    {
        _linkLabel.Click -= new EventHandler(_label_Click);
        base.DisposeManagedResources();
    }

    protected override void SetContentCore(object value)
    {
        _linkLabel.Text = value.ToString();
    }

    protected override SizeF ArrangeOverride(SizeF finalSize)
    {
        if (this.Children.Count == 2)
        {
            var label = this.Children[0];
            var link = this.Children[1];

            var labelWidth = Math.Min(finalSize.Width, label.DesiredSize.Width);
            var linkWidth = Math.Min(link.DesiredSize.Width, finalSize.Width - labelWidth);

            label.Arrange(new RectangleF(
                0,
                (finalSize.Height / 2) - (label.DesiredSize.Height / 2),
                labelWidth,
                label.DesiredSize.Height));

            link.Arrange(new RectangleF(
                label.Size.Width,
                (finalSize.Height / 2) - (link.DesiredSize.Height / 2),
                linkWidth,
                link.DesiredSize.Height));
        }
        return finalSize;
    }

    public override bool IsCompatible(GridViewColumn data, object context)
    {
        return data is GridViewHyperlinkColumn && context is GridDataRowElement;
    }
}

[Martin Vasilev]

Hello Christoph,

Thank you for writing.

In order to achieve your requirement, you should override MeasureOverride method for your custom cell element. Please consider the following code as an example:

protected override SizeF MeasureOverride(SizeF availableSize)
        {
            SizeF arrangedSize = TableElement.ViewElement.RowLayout.ArrangeCell(new RectangleF(Point.Empty, availableSize), this).Size;
            SizeF desiredSize = SizeF.Empty;
            SizeF clientSize = GetClientRectangle(availableSize).Size;

            _headerLabel.Measure(clientSize);
            _linkLabel.Measure(new SizeF(clientSize.Width - _headerLabel.DesiredSize.Width - 5, clientSize.Height));

            desiredSize.Width += _headerLabel.DesiredSize.Width + _linkLabel.DesiredSize.Width;
            desiredSize.Height = Math.Max(Math.Max(desiredSize.Height, _headerLabel.DesiredSize.Height), _linkLabel.DesiredSize.Height);

            if (!float.IsInfinity(availableSize.Width))
            {
                desiredSize.Width = arrangedSize.Width;
            }
            if (!float.IsInfinity(availableSize.Height))
            {
                desiredSize.Height = arrangedSize.Height;
            }

            return desiredSize;
        }

I hope this helps. Let me know if you have any other questions.

Best wishes,
Martin Vasilev
the Telerik team

[Christoph]

Hi Martin,

Thank you very much. Now my cell-element behaves exactly as I want.

Best wishes, Christoph