Creating Diagonal Pattern in WPF

Question

I want to create diagonal hatch pattern in WPF. I am using following XAML code to generate it:

Answer 1

Here the coded variant to @Balázs solution (in VB)

    Public ReadOnly Property fill As Brush
        Get
            Dim FillColor As Color
            Dim HatchThickness As Double
            Dim HatchAngle As Double

            FillColor = Colors.Black
            HatchThickness = 3
            HatchAngle = 45

            '
            ' https://stackoverflow.com/questions/42667566/creating-diagonal-pattern-in-wpf
            ' and
            ' https://docs.microsoft.com/en-us/dotnet/framework/wpf/graphics-multimedia/wpf-brushes-overview#paint-with-a-drawing
            '
            Dim myBrush As New DrawingBrush()

            Dim myGeometryGroup As New GeometryGroup()

            '
            ' add a horizontal line to the geometry group
            '
            myGeometryGroup.Children.Add(New LineGeometry(New Windows.Point(0, 0), New Windows.Point(10, 0)))

            '
            ' draw geometry with transparent brush and pen as defined
            '
            Dim p As New Windows.Media.Pen
            p.Brush = New SolidColorBrush(FillColor)
            p.Thickness = HatchThickness
            p.StartLineCap = PenLineCap.Square
            p.EndLineCap = PenLineCap.Square

            Dim myDrawing As New GeometryDrawing(Nothing, p, myGeometryGroup)

            '
            ' apply the drawing to the brush
            '
            myBrush.Drawing = myDrawing

            '
            ' in case, there is more than one line use a Drawing Group
            '

            'Dim myDrawingGroup As New DrawingGroup()
            'myDrawingGroup.Children.Add(checkers)
            'myBrush.Drawing = myDrawingGroup

            ' set viewbox and viewport
            myBrush.Viewbox = New Windows.Rect(0, 0, 10, 10)
            myBrush.ViewboxUnits = BrushMappingMode.Absolute
            myBrush.Viewport = New Windows.Rect(0, 0, 10, 10)
            myBrush.ViewportUnits = BrushMappingMode.Absolute
            myBrush.TileMode = TileMode.Tile
            myBrush.Stretch = Stretch.UniformToFill
            ' rotate
            myBrush.Transform = New RotateTransform(HatchAngle)

            Return myBrush

        End Get
    End Property

and in C#

public Brush fill
{
    get
    {
        Color FillColor;
        double HatchThickness;
        double HatchAngle;

        FillColor = Colors.Black;
        HatchThickness = 3;
        HatchAngle = 45;

        // 
        // https://stackoverflow.com/questions/42667566/creating-diagonal-pattern-in-wpf
        // and
        // https://docs.microsoft.com/en-us/dotnet/framework/wpf/graphics-multimedia/wpf-brushes-overview#paint-with-a-drawing
        // 
        DrawingBrush myBrush = new DrawingBrush();

        GeometryGroup myGeometryGroup = new GeometryGroup();

        // 
        // add a horizontal line to the geometry group
        // 
        myGeometryGroup.Children.Add(new LineGeometry(new Windows.Point(0, 0), new Windows.Point(10, 0)));

        // 
        // draw geometry with transparent brush and pen as defined
        // 
        Windows.Media.Pen p = new Windows.Media.Pen();
        p.Brush = new SolidColorBrush(FillColor);
        p.Thickness = HatchThickness;
        p.StartLineCap = PenLineCap.Square;
        p.EndLineCap = PenLineCap.Square;

        GeometryDrawing myDrawing = new GeometryDrawing(null/* TODO Change to default(_) if this is not a reference type */, p, myGeometryGroup);

        // 
        // apply the drawing to the brush
        // 
        myBrush.Drawing = myDrawing;

        // 
        // in case, there is more than one line use a Drawing Group
        // 

        // Dim myDrawingGroup As New DrawingGroup()
        // myDrawingGroup.Children.Add(checkers)
        // myBrush.Drawing = myDrawingGroup

        // set viewbox and viewport
        myBrush.Viewbox = new Windows.Rect(0, 0, 10, 10);
        myBrush.ViewboxUnits = BrushMappingMode.Absolute;
        myBrush.Viewport = new Windows.Rect(0, 0, 10, 10);
        myBrush.ViewportUnits = BrushMappingMode.Absolute;
        myBrush.TileMode = TileMode.Tile;
        myBrush.Stretch = Stretch.UniformToFill;
        // rotate
        myBrush.Transform = new RotateTransform(HatchAngle);

        return myBrush;
    }
}