GanttControl.CustomDrawTimescaleColumn Event

Fires before a column in the chart area is displayed. Provides access to a drawing surface and allows you to draw the column manually.

Namespace: DevExpress.XtraGantt

Assembly: DevExpress.XtraGantt.v21.2.dll

NuGet Packages: DevExpress.Win.Design, DevExpress.Win.Gantt

Declaration

C#

[DXCategory("Events")]
public event CustomDrawTimescaleColumnEventHandler CustomDrawTimescaleColumn

VB.NET

<DXCategory("Events")>
Public Event CustomDrawTimescaleColumn As CustomDrawTimescaleColumnEventHandler

Event Data

The CustomDrawTimescaleColumn event's data class is CustomDrawTimescaleColumnEventArgs. The following properties provide information specific to this event:

Property	Description
Cache	Provides access to the drawing surface and a cache of brushes, pens, fonts, and other graphics. Inherited from CustomDrawEventArgs.
Column	Gets the processed column.
Handled	Gets or sets whether the event is handled and allows you to prevent the control from drawing the visual element in its default appearance. Inherited from CustomDrawEventArgs.

The event data class exposes the following methods:

Method	Description
DefaultDraw()	Draws the visual element in its default appearance. Inherited from CustomDrawEventArgs.
DrawBackground()	Draws the background.
DrawHeader()	Draws the header.
GetPosition(DateTime)	Returns the position of the column that corresponds to the specified date.

Examples

The code below shows how to display a deadline.

Run Demo: Draw a Deadline

C#

DateTime deadLine = TaskStorage.GetFinishDateFromTask("Deploy Beta");
ganttControl.CustomDrawTimescaleColumn += (sender, e) => {
    GanttTimescaleColumn column = e.Column;
    if(column.StartDate <= deadLine && column.FinishDate >= deadLine) {
        e.DrawBackground();
        float x = (float)e.GetPosition(deadLine); float width = 4;
        RectangleF deadLineRect = new RectangleF(x, column.Bounds.Y, width, column.Bounds.Height);
        e.Cache.FillRectangle(DXSkinColors.FillColors.Danger, deadLineRect);
        e.DrawHeader();
        e.Handled = true;
    }
};

VB.NET

Dim deadLine As Date = TaskStorage.GetFinishDateFromTask("Deploy Beta")
AddHandler ganttControl.CustomDrawTimescaleColumn, Sub(sender, e)
    Dim column As GanttTimescaleColumn = e.Column
    If column.StartDate <= deadLine AndAlso column.FinishDate >= deadLine Then
        e.DrawBackground()
        Dim x As Single = CSng(e.GetPosition(deadLine))
        Dim width As Single = 4
        Dim deadLineRect As New RectangleF(x, column.Bounds.Y, width, column.Bounds.Height)
        e.Cache.FillRectangle(DXSkinColors.FillColors.Danger, deadLineRect)
        e.DrawHeader()
        e.Handled = True
    End If
End Sub

The code below shows how to draw striplines.

Run Demo: Draw Striplines

C#

DateTime striplineStart = DateTime.Now.AddHours(5);
DateTime striplineEnd = striplineStart.AddHours(4);
Color striplineColor = Color.FromArgb(128, 255, 224, 166);
ganttControl.CustomDrawTimescaleColumn += (sender, e) => {
    GanttTimescaleColumn column = e.Column;
    float stripLineStartPoint = (float)Math.Max(e.GetPosition(striplineStart), column.Bounds.Left);
    float stripLineEndPoint = (float)Math.Min(e.GetPosition(striplineEnd), column.Bounds.Right);
    e.DrawBackground();
    RectangleF boundsToDraw = new RectangleF(stripLineStartPoint, column.Bounds.Y, stripLineEndPoint - stripLineStartPoint, column.Bounds.Height);
    if(boundsToDraw.Width > 0)
        e.Cache.FillRectangle(striplineColor, boundsToDraw);
    e.DrawHeader();
    e.Handled = true;
};

VB.NET

Dim striplineStart As Date = Date.Now.AddHours(5)
Dim striplineEnd As Date = striplineStart.AddHours(4)
Dim striplineColor As Color = Color.FromArgb(128, 255, 224, 166)
AddHandler ganttControl.CustomDrawTimescaleColumn, Sub(sender, e)
    Dim column As GanttTimescaleColumn = e.Column
    Dim stripLineStartPoint As Single = CSng(Math.Max(e.GetPosition(striplineStart), column.Bounds.Left))
    Dim stripLineEndPoint As Single = CSng(Math.Min(e.GetPosition(striplineEnd), column.Bounds.Right))
    e.DrawBackground()
    Dim boundsToDraw As New RectangleF(stripLineStartPoint, column.Bounds.Y, stripLineEndPoint - stripLineStartPoint, column.Bounds.Height)
    If boundsToDraw.Width > 0 Then
        e.Cache.FillRectangle(striplineColor, boundsToDraw)
    End If
    e.DrawHeader()
    e.Handled = True
End Sub