Abstract

Sometimes we need to display elements of the Cube Tree Structure in a different way: for example, mark out the used or recommended elements.

Content

You can override the drawing of the Tree Structure elements in the TOLAPGrid.OnDrawTreeNode event.

The OnDrawTreeNode event argument’s properties:
TEventDrawTreeNodeArgs.DrawDefault — defines the type of drawing (standard or custom). If set to False, there will be no standard drawing of the Tree element.
TEventDrawTreeNodeArgs.IsUsing — the Tree element was used in pivot-panels
TEventDrawTreeNodeArgs.Graphics — a Graphics type object for the custom drawing
TEventDrawTreeNodeArgs.Node — the element to be drawn
TEventDrawTreeNodeArgs.Data — node data (measure, hierarchy, etc)

There are three ways of drawing a Tree

1. Default Drawing

Applied when:
• no additional operations with the OnDrawTreeNode or the CubeStructureTree are performed
• the flag e.DrawDefault = true in the OnDrawTreeNode event handler and the default TOLAPGrid.CubeStructureTree.DrawMode == TreeViewDrawMode.OwnerDrawText is kept unchanged
• if TOLAPGrid.CubeStructureTree.DrawMode == TreeViewDrawMode.Normal the event handler will not be called

2. Text Amended Drawing

You can change the text of the Tree nodes. For that, you need:
• Set the property value TOLAPGrid.CubeStructureTree.DrawMode == TreeViewDrawMode.OwnerDrawText
• In the OnDrawTreeNode event handler, draw the text of the Tree node.

3. Custom Drawing of the Text and Other Elements of the Node

For the fully custom drawing of the Tree nodes you need:
• Set the value TOLAPGrid.CubeStructureTree.DrawMode == TreeViewDrawMode.OwnerDrawAll
• In the event handler OnDrawTreeNode, draw all the elements of the Tree node. Note: the property e.Bounds of the event argument returns a rectangle with the node.

By default the custom drawing text mode is set for the TOLAPGrid.CubeStructureTree object (TOLAPGrid.CubeStructureTree.DrawMode == TreeViewDrawMode.OwnerDrawText). You can change the drawing mode through the Tree’s property: TOLAPGrid.CubeStructureTree.DrawMode == TreeViewDrawMode.OwnerDrawText

An example of the event handler: the already used dimensions will be displayed in bold red letters, and the already used hierarchies – in bold light-yellow letters.

void Grid_OnDrawTreeNode(object Sender, TEventDrawTreeNodeArgs e)
{
    e.DrawDefault = true;

    if (e.IsUsing)
    {
        e.DrawDefault = false;
        Brush brush = new SolidBrush(Color.Red);
        if (e.Data is THierarchy)
            brush = new SolidBrush(Color.Lime);
        Font font = new Font(Grid.CubeStructureTree.Font, FontStyle.Bold);
        e.Graphics.DrawString(e.Node.Text, font, brush, e.Bounds.Location);
    }
}

In the derived objects of the TOLAPGrid, for the better control over the drawing process, you can reload the protected method: TOLAPGrid.DrawTreeNode(TEventDrawTreeNodeArgs e)