Gridlines in WPF Diagram (SfDiagram)

Gridlines are crisscross lines drawn in diagram page like the lines on traditional graph paper. It helps to position the diagram elements on the diagram page.

The SnapConstraints property of SnapSettings class allows you to control the visibility of the gridlines.

<!--Initialize SfDiagram-->
<syncfusion:SfDiagram x:Name="diagram">
    <!--Initialize SnapSettings constraints to show Gridlines-->
    <syncfusion:SfDiagram.SnapSettings>
        <syncfusion:SnapSettings SnapConstraints="ShowLines"/>
    </syncfusion:SfDiagram.SnapSettings>
</syncfusion:SfDiagram>
//Initialize SfDiagram
SfDiagram diagram = new SfDiagram();
//Initialize SnapSettings constraints to show Gridlines
diagram.SnapSettings = new SnapSettings()
{
    SnapConstraints = SnapConstraints.ShowLines,
};
Enum Value Output
SnapConstraints None Snap to Gridlines
  VerticalLines Snap to Gridlines
  HorizontalLines Snap to Gridlines
  ShowLines Snap to Gridlines

Change grid lines appearance

The HorizontalGridLines and VerticalGridLines properties of SnapSettings class allows you to customize the appearance of the gridlines.

<!--Style for Gridlines-->
<local:Gridlinestyle x:Key="gridlinestyle">
    <Style TargetType="Path">
        <Setter Property="Stroke" Value="Blue"/>
        <Setter Property="StrokeDashArray" Value="3"/>
    </Style>
</local:Gridlinestyle>

<!--Initialize SfDiagram-->
<syncfusion:SfDiagram x:Name="diagram" >
    <!--Initialize Snap Settings-->
    <syncfusion:SfDiagram.SnapSettings>
        <syncfusion:SnapSettings SnapConstraints="ShowLines">
            <!--Initialize Horizontal Gridlines-->
            <syncfusion:SnapSettings.HorizontalGridlines>
                <syncfusion:Gridlines Strokes="{StaticResource gridlinestyle}"/>
            </syncfusion:SnapSettings.HorizontalGridlines>
            <!--Initialize Vertical Gridlines-->
            <syncfusion:SnapSettings.VerticalGridlines>
                <syncfusion:Gridlines Strokes="{StaticResource gridlinestyle}"/>
            </syncfusion:SnapSettings.VerticalGridlines>
        </syncfusion:SnapSettings>
    </syncfusion:SfDiagram.SnapSettings>
</syncfusion:SfDiagram>
//Initialize SfDiagram
SfDiagram diagram = new SfDiagram();
//Style for Gridlines
Style pathStyle = new Style(typeof(Path));
pathStyle.Setters.Add(new Setter(Shape.StrokeProperty, new SolidColorBrush(Colors.Blue)));
pathStyle.Setters.Add(new Setter(Shape.StrokeDashArrayProperty, new DoubleCollection() { 3, 3 }));

//Initialize SnapSettings constraints with HorizontalGridlines and VerticalGridlines values
diagram.SnapSettings = new SnapSettings()
{
    SnapConstraints = SnapConstraints.ShowLines,
    HorizontalGridlines = new Gridlines()
    {
        Strokes = new Gridlinestyle { pathStyle }
    },
    VerticalGridlines = new Gridlines()
    {
        Strokes = new Gridlinestyle { pathStyle }
    },
};

//Creates collection for the style.
public class Gridlinestyle : List<Style>
{
}

Snap to Gridlines

Change grid spacing

The thickness and space between the gridlines can be customized by using LinesInterval property of Gridlines class. The LinesInterval is a type of List collection, where the values at the odd indexes are referred as thickness of the lines and the values at the even indexes are referred as space between the gridlines.

<!--Initializes the double collection-->
<local:Intervals x:Key="Intervals">
    <!--Thickness of the grid line-->
    <sys:Double>0.25</sys:Double>
    <!--Space between each gridlines-->
    <sys:Double>10</sys:Double>
    <sys:Double>0.5</sys:Double>
    <sys:Double>20</sys:Double>
    <sys:Double>1</sys:Double>
    <sys:Double>30</sys:Double>
    <sys:Double>1.25</sys:Double>
    <sys:Double>40</sys:Double>
    <sys:Double>1.5</sys:Double>
    <sys:Double>50</sys:Double>
</local:Intervals>

<!--Initialize SfDiagram-->
<syncfusion:SfDiagram x:Name="diagram" >
    <syncfusion:SfDiagram.SnapSettings>
        <syncfusion:SnapSettings SnapConstraints="ShowLines">
            <!--Initialize Horizontal Gridlines-->
            <syncfusion:SnapSettings.HorizontalGridlines>
                <syncfusion:Gridlines LinesInterval="{StaticResource Intervals}" />
            </syncfusion:SnapSettings.HorizontalGridlines>
            <!--Initialize Vertical Gridlines-->
            <syncfusion:SnapSettings.VerticalGridlines>
                <syncfusion:Gridlines LinesInterval="{StaticResource Intervals}"/>
            </syncfusion:SnapSettings.VerticalGridlines>
        </syncfusion:SnapSettings>
    </syncfusion:SfDiagram.SnapSettings>
</syncfusion:SfDiagram>
//Initialize SfDiagram
SfDiagram diagram = new SfDiagram();

//Initialize the double collection
Intervals intervals = new Intervals { 0.25, 10, 0.5, 20, 1, 30, 1.25, 40, 1.5, 50 };
//Initialize Snap Setting constraints with HorizontalGridlines and VerticalGridlines values
diagram.SnapSettings = new SnapSettings()
{
    SnapConstraints = SnapConstraints.ShowLines,
    HorizontalGridlines = new Gridlines()
    {
        //Define lines interval value
        LinesInterval = intervals,
    },
    VerticalGridlines = new Gridlines()
    {
        //Define lines interval value
        LinesInterval = intervals,
    },
};

//Creates collection for the double values.
public class Intervals : List<double>
{
}

Snap to Gridlines

Find the Gridlines sample to depict the Gridlines.

See Also

How to snap the objects on gridlines