A Time-Of-Day Picker control

• Download source files - 16 Kb
• Download demo project - 10.9 Kb

Introduction

This control uses double buffering to provide an interface that allows a user to choose time frames throughout the day. The control is modeled after a control that originally showed up in Windows NT, which allowed a user to specify valid login hours to the domain.

About the control

The control has a property called TimeFrames that returns a 3 dimensional array of TimeSpan objects.

public TimeSpan[][][] TimeFrames

• The first dimension is the day
• The second dimension is a specific contiguous time span
• The third dimension will only have two elements, the first is the start time and the second is the end time

As suggested in the Eric White & Chris Garrett text "GDI+ Programming: Creating Custom Controls Using C#", all sections of the screen are split up into seperate objects. Since all major areas of the control can be hot tracked or selected, there is a base concept of a TimeFrameObject, which all sub areas inherit from. This base class includes members for the bounds of the object and whether the object is hot tracked or selected. This really cuts down on the code. For example, this method figures out where on the screen a particular point is and figures out which TimeFrameObject contains the point.

private TimeFrameObject GetTimeFrameObject( MouseEventArgs e )
{
    TimeFrameObject tfo = null;
    if( Grid.Contains( e.X, e.Y ) )
    {
        tfo = CellMatrix[ (int)( ( e.Y - Header ) / y_grid_inc), 
                (int)( ( e.X - LeftMargin ) / x_grid_inc) ];
    }
    else if( ( e.X > Grid.X ) && ( e.X < 
            ( Grid.X + Grid.Width ) ) && ( e.Y < Grid.Y ) )
    {
        tfo = (TimeFrameObject)
            TimeSlots[ (int)( ( e.X - LeftMargin ) / x_grid_inc) ];
    }
    else if( ( e.X < Grid.X ) && 
            ( e.Y < ( Grid.Y + Grid.Height ) ) && ( e.Y > Grid.Y ) )
    {
        tfo = (_Day)Days[ (int)( ( e.Y - Header ) / y_grid_inc) ];
    }
    else if( TopLeft.Contains( e.X, e.Y ) )
    {
        tfo = TopLeft;
    }
    return tfo;
}

This reduces OnMouseDown to:

protected override void OnMouseDown( MouseEventArgs e )
{
    TimeFrameObject tfo = GetTimeFrameObject( e );
    if( tfo != null )
    {
        if( e.Button == MouseButtons.Left )
        {
            tfo.Selected = ! tfo.Selected;
            tfoLastSelected = tfo;
            this.Invalidate( true );
        }
    }
}

That's all