Create an Interactive BPMN Editor Using the WPF Diagram Control
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Create an Interactive BPMN Editor Using the WPF Diagram Control

A business process can be confusing for anyone who is not directly involved with the process. A Business Process Model and Notation (BPMN) diagram creates a visual representation of a complex business process in a form similar to a flowchart. We can share such diagrams across organizations and industries to communicate the necessary information to complete a process.

In this blog, we will see how to easily create a BPMN editor with an interactive user interface using the Syncfusion WPF Diagram control. In the course of this explainer, we’ll also see how to use the rich set of features available in the WPF Diagram control to give your app a better user experience.

Let’s start!

Creating a BPMN Editor Using the WPF Diagram Control
Creating a BPMN Editor Using the WPF Diagram Control

BPMN shapes

The BPMN shapes help us to represent internal business processes in a graphical notation. They enable you to communicate procedures in a standard manner. These shapes are popular and intuitive graphics that can be easily understood by all business stakeholders, including business users, business analysts, software developers, and data architects.

The WPF Diagram control supports the following BPMN shapes:

ShapeSymbolDescription
EventEvent BPMN ShapeRepresents something that happens during a business process.
GatewayGateway BPMN ShapeUsed to control the flow of a process.
ActivityActivity BPMN ShapeDescribes the kind of work being done in a particular process instance.
MessageMessage BPMN ShapeThe content of a communication.
DataStoreDataStore BPMN ShapeStore or access data associated with a business process.
DataObjectDataObject BPMN ShapeRepresents information flowing with the process. Examples: data placed into a process, data resulting from a process, or data that needs to be collected or stored.
TextAnnotationTextAnnotation BPMN ShapePoints at or references another BPMN shape.
GroupGroup BPMN ShapeOrganizes tasks or processes that are significant in the overall process.
ExpandedSubProcessExpandedSubProcess BPMN ShapeThe extended version of the Group symbol.
SequenceFlowSequenceFlow BPMN ShapeRepresents the typical path between two flow objects.
DefaultSequenceFlowDefaultSequenceFlow BPMN ShapeRepresents the default sequence flow when other conditional flows are not valid. It is indicated by a backslash at the beginning of the sequence.
ConditionalSequenceflowConditionalSequenceflow BPMN ShapeControls the flow of a process based on certain conditions.
AssociationAssociation BPMN ShapeRepresents a relationship between artifacts and flow objects. This is represented as a dotted line.
DirectionalAssociationDirectionalAssociation BPMN ShapeA directional association is used with data objects to show that they are either an input or output from an activity. This is represented as a dotted line with an arrow at one end.
BiDirectionalAssociationBiDirectionalAssociation BPMN ShapeA bidirectional association is used with data objects to show that they are both input and output from an activity. This is represented as a dotted line with an arrow at both ends.
MessageFlowMessageFlow BPMN ShapeShows the flow of messages between two participants.
InitiatingMessageflowInitiatingMessageflow BPMN ShapeRepresents an activity or event in one pool which can initiate a message to another pool.
NonInitiatingMessageflowNonInitiatingMessageflow BPMN ShapeRepresents an activity or event in one pool which can’t initiate a message to another pool.

Create the WPF application

Refer to the documentation on creating your first WPF app to build a new WPF app using Visual Studio and run it.

Create the BPMN editor surface using WPF Diagram control

Add the WPF Diagram (SfDiagram) control to the app by dragging it from the Toolbox and dropping it in the Designer view. You can also manually add it using the XAML/C# code.

The following code example shows how to add the diagram canvas to your WPF application.

<syncfusion:SfDiagram Grid.Column="1">
    <syncfusion:SfDiagram.HorizontalRuler>
        <syncfusion:Ruler/>
    </syncfusion:SfDiagram.HorizontalRuler>
    <syncfusion:SfDiagram.SnapSettings>
        <syncfusion:SnapSettings SnapConstraints="ShowLines"/>
    </syncfusion:SfDiagram.SnapSettings>
    <syncfusion:SfDiagram.VerticalRuler>
        <syncfusion:Ruler Orientation="Vertical"/>
    </syncfusion:SfDiagram.VerticalRuler>
    <syncfusion:SfDiagram.Nodes>
        <syncfusion:NodeCollection/>
    </syncfusion:SfDiagram.Nodes>
    <syncfusion:SfDiagram.Connectors>
        <syncfusion:ConnectorCollection/>
    </syncfusion:SfDiagram.Connectors>
    <syncfusion:SfDiagram.Groups>
        <syncfusion:GroupCollection/>
    </syncfusion:SfDiagram.Groups>
</syncfusion:SfDiagram>

The following screenshot shows the created diagramming page.

Creating the Diagram Canvas in the WPF Application
Creating the Diagram Canvas in the WPF Application

Note: For more details, refer to the Getting Started with WPF Diagram documentation.

Create reusable BPMN symbols using WPF Diagram control

The WPF Diagram control provides a gallery of reusable symbols and diagram elements called stencil. We can drag and drop them onto the diagram canvas any number of times.

Let’s see how to create stencils using our built-in BPMN shapes. The WPF Diagram control provides a set of predefined categories of shapes. We can load the built-in shape categories into the stencils by specifying the Keys and Title properties of the StencilCategory class. The properties do the following:

  • Keys: Specifies the static resource key name value of the category collection.
  • Title: Specifies the title that should be displayed as a header of the category collection.

The following code explains how to create stencils with the BPMN shapes using the BPMNEditorShapes categories.

<syncfusion:Stencil x:Name="stencil" Grid.Column="0" BorderThickness="0,1,1,1" Title="Shapes">
    <syncfusion:Stencil.Categories>
        <syncfusion:StencilCategoryCollection>
            <!--Specify the basic shapes category with title and resource key-->
            <syncfusion:StencilCategory Title="BPMN Shapes" Keys="{StaticResource BPMNEditorShapes}"/>
        </syncfusion:StencilCategoryCollection>
    </syncfusion:Stencil.Categories>
    <syncfusion:Stencil.SymbolGroups>
        <syncfusion:SymbolGroups>
            <!--Separate groups based on the key-->
            <syncfusion:SymbolGroupProvider MappingName="Key"/>
        </syncfusion:SymbolGroups>
    </syncfusion:Stencil.SymbolGroups>
</syncfusion:Stencil>

The following screenshot shows the collection of BPMN editor shapes as stencils.

A Gallery of Reusable BPMN Shapes in the WPF Diagram Control
A Gallery of Reusable BPMN Shapes in the WPF Diagram Control

Note: Refer to the Stencil in WPF Diagram documentation for more info on adding custom shapes, shape categories, and customizing the stencil appearances.

Create the BPMN diagram editor using WPF Diagram control

Now we can easily create the BPMN diagram editor using the WPF Diagram control by dragging and dropping the BPMN symbols from the stencils, and then arranging and connecting them.

Step #1: Add BPMN symbols to the editor

Start by dragging symbols onto the diagramming canvas from the BPMN Shapes stencils. Arrange them into an order that makes it clear where the business process start and endpoints are, and how the various nodes are linked. People who read the diagram should be able to see where to start and how to follow the connections.

Refer to the following GIF image.

Adding BPMN Symbols to the Canvas in the WPF Diagram Control
Adding BPMN Symbols to the Canvas in the WPF Diagram Control

Step #2: Connect BPMN symbols

Each diagram symbol has a Draw quick command Draw quick command  which is visible on selecting any diagram symbol. This quick command helps us to create a connection between symbols by clicking and dragging a connector and dropping it on another symbol.

Refer to the following GIF image.

Connecting BPMN Shapes in BPMN Diagram Using the Draw Quick Command in WPF Diagram Control
Connecting BPMN Shapes in BPMN Diagram Using the Draw Quick Command in WPF Diagram Control

Note: Refer to the Quick Command in WPF Diagram Control documentation to learn how to add or remove default/custom quick commands in your app and customize their appearance.

You can also create connectors by selecting the Connector tool Connector tool  from the toolbar or using the Tools > Connector tool menu option. Click a symbol and drag a connector to another shape. When you are done, click the Pointer tool Pointer tool  on the toolbar to select the symbols.

Creating Connectors Using Connector and Pointer Tools in WPF Diagram Control
Creating Connectors Using Connector and Pointer Tools in WPF Diagram Control

Note: For more details, refer to the Tools in WPF Diagram documentation.

Step #3: Add labels to symbols

To add text to any BPMN node, double-tap on the node or select the node and press F2. A text box will appear to type the required text. When you are done, press the Esc key or deselect the node.

Refer to the following GIF image.

Adding Labels to Nodes in WPF Diagram Control
Adding Labels to Nodes in WPF Diagram Control

Note: Refer to the Annotations in WPF Diagram documentation to see how to add labels in your diagram and customize its appearance.

Step #4: Load and save a diagram

The WPF Diagram control provides the flexibility to save your current work and resume it by loading the saved diagram back to the diagram canvas. Use the Save button Save button  to save your current diagram to the local drive and use the Open button Open button  to load the existing diagram file from your local drive.

Refer to the following GIF image.

Loading and Saving a BPMN Diagram in the WPF Diagram Control
Loading and Saving a BPMN Diagram in the WPF Diagram Control

Note: Refer to the loading and saving diagrams in WPF Diagram documentation.

Step #5: Export the diagram

You can export the diagram to PDF format or an image format (JPEG, PNG, BMP, TIF, GIF, and more). To do so, click the Export button Export button  or select the File > Export menu command.

Exporting the BPMN Diagram in Image Format
Exporting the BPMN Diagram in Image Format

Note: For more details, refer to the Exporting in WPF Diagram documentation.

Step #6: Print the diagram

Print a diagram by clicking the Print button Print button  in the toolbar or selecting the File > Print menu command.

The following screenshot shows the Print Diagram dialog along with the custom print options.

Diagram Print Options
Diagram Print Options

Note: For more details, refer to the Printing in WPF Diagram documentation.

Step 7: Pan and zoom

The WPF Diagram control provides support to pan and zoom the diagram in different ways.

Pan and zoom using the keyboard

  1. Press and hold the Ctrl and Shift keys. The pointer will turn into a magnifying glass.
  2. Do any of the following:
  • Click the left mouse button to enlarge the view.
  • Click the right mouse button to reduce the view.
  • Click and drag the left mouse button over a region you want to zoom into.
  • Right-click and drag to pan the diagram.

Pan and zoom using the scroll wheel

Do any of the following:

  • To scroll up or down, rotate the scroll wheel forward or backward.
  • To scroll left or right, hold down Shift as you rotate the scroll wheel forward or backward.
  • To zoom in or out, hold down Ctrl as you rotate the scroll wheel forward or backward.

Zoom using the zoom controls

The zoom controls are in the Zoom ribbon bar of the View tab. Click the Zoom Out and Zoom In buttons to change the zoom level of the diagram. Also, you can make the entire diagram fit into the current view by clicking the Fit to Window button.

Pan using the pan tool

You can pan the diagram by selecting the Pan tool Pan tool  from the Tools ribbon bar of the Home tab. Then, click and drag the mouse to pan the diagram.

GitHub reference

You can download an example of creating a BPMN editor using WPF Diagram control from GitHub.

Conclusion

Thanks for reading! In this blog, we have seen how to create an interactive BPMN editor using the versatile features of the Syncfusion WPF Diagram control. Now we can easily demonstrate business workflows! Try it out and leave feedback in the comments section below!

Similarly, you can use our Diagram control to build editors for organizational charts, flowcharts, network diagrams, or logic circuit diagrams.

If you’re already a Syncfusion user, you can download the product setup from our website. Otherwise, you can download a 30-day free trial.

You can contact us through our support forumsupport portal, or feedback portal. We are always happy to assist you.

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Sarathkumar V

Meet the Author

Sarathkumar V

Sarathkumar is a Product Manager for Diagram and HeatMap products at Syncfusion. He has been a .NET developer since 2013. He is specialized in WPF, UWP, Xamarin and other .Net frameworks.