GanttControl.CustomDrawTaskDependency Event

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

Namespace: DevExpress.XtraGantt

Assembly: DevExpress.XtraGantt.v19.2.dll

Declaration

C#

[DXCategory("Events")]
public event CustomDrawTaskDependencyEventHandler CustomDrawTaskDependency

VB.NET

<DXCategory("Events")>
Public Event CustomDrawTaskDependency As CustomDrawTaskDependencyEventHandler

Event Data

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

Property	Description
Appearance	Provides access to appearance settings that specify the dependency line background color.
Points	Provides access to a list of points (coordinates relative to the control’s upper left corner) that specify the dependency line.
PredecessorFinishDate	Gets or sets the predecessor node’s finish date.
PredecessorNode	Gets the predecessor node.
State	Gets the object state: normal, hot tracked, pressed, disabled, or selected.
SuccessorNode	Gets the successor node.
SuccessorStartDate	Gets or sets the successor node’s start date.

The event data class exposes the following methods:

Method	Description
DefaultDraw()	Draws the task dependency line.
DefaultDraw(IList<PointF>)	Draws the task dependency line.

Example

The code below shows how to indicate a critical path in the project.

C#

HashSet<int> criticalPathIds = new HashSet<int> { 1, 2, 3, 6, 7, 8, 10, 11, 13 };
ganttControl.CustomDrawTask += (sender, e) => {
    int taskId = Convert.ToInt32(e.Node.GetValue("Id"));
    if(criticalPathIds.Contains(taskId)) {
        e.Appearance.BackColor = DXSkinColors.FillColors.Danger;
        e.Appearance.ProgressColor = DXSkinColors.FillColors.Danger;
    }
};
ganttControl.CustomDrawTaskDependency += (sender, e) => {
    int predecessorId = Convert.ToInt32(e.PredecessorNode.GetValue("Id"));
    int successorId = Convert.ToInt32(e.SuccessorNode.GetValue("Id"));
    if(criticalPathIds.Contains(predecessorId) && criticalPathIds.Contains(successorId)) {
        e.Appearance.BackColor = DXSkinColors.FillColors.Danger;
    }
};

VB.NET

Dim criticalPathIds As New HashSet(Of Integer)() From {1, 2, 3, 6, 7, 8, 10, 11, 13}
AddHandler ganttControl.CustomDrawTask, Sub(sender, e)
    Dim taskId As Integer = Convert.ToInt32(e.Node.GetValue("Id"))
    If criticalPathIds.Contains(taskId) Then
        e.Appearance.BackColor = DXSkinColors.FillColors.Danger
        e.Appearance.ProgressColor = DXSkinColors.FillColors.Danger
    End If
End Sub
AddHandler ganttControl.CustomDrawTaskDependency, Sub(sender, e)
    Dim predecessorId As Integer = Convert.ToInt32(e.PredecessorNode.GetValue("Id"))
    Dim successorId As Integer = Convert.ToInt32(e.SuccessorNode.GetValue("Id"))
    If criticalPathIds.Contains(predecessorId) AndAlso criticalPathIds.Contains(successorId) Then
        e.Appearance.BackColor = DXSkinColors.FillColors.Danger
    End If
End Sub

The code below shows how to split a task’s bar into two bars.

C#

ganttControl.CustomDrawTask += (sender, e) => {
    if(e.Node.Id == 3) {
        e.Appearance.BackColor = DXSkinColors.FillColors.Danger;
        e.Appearance.ProgressColor = DXSkinColors.FillColors.Danger;
        TimeSpan offset = TimeSpan.FromHours(2);
        e.DrawShape(e.Info.StartDate + offset, e.Info.FinishDate - offset);
        e.DrawRightText();
        e.Handled = true;
    }
};

VB.NET

AddHandler ganttControl.CustomDrawTask, Sub(sender, e)
    If e.Node.Id = 3 Then
        e.Appearance.BackColor = DXSkinColors.FillColors.Danger
        e.Appearance.ProgressColor = DXSkinColors.FillColors.Danger
        Dim offset As TimeSpan = TimeSpan.FromHours(2)
        e.DrawShape(e.Info.StartDate + offset, e.Info.FinishDate - offset)
        e.DrawRightText()
        e.Handled = True
    End If
End Sub

Note

Run the Gantt Code Examples demo to see the complete example.