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Xml deserialization speed?
Using LoadFromString?
Using LoadFromXml?
Convert FlowChart To Image?
Convert shape to an image?
Exporting a diagram to emf file?
Saving a Selection?
Drawing database ER diagrams with FlowChart.NET?
Generating FlowChart Diagram from SQL-Data?
Q: Has the XML deserialization speed been improved in the Diagram.LoadFromXml in v5?
A: Version 5 uses the DOM API and version 4 used linear serialization, so the XML serialization is a bit slower in V5, but you will notice it only with a big number of items (in the thousands). In addition, version 5 serializes saved a single copy of shared node images, so XML serialization in the new version is much faster when using images.
We have done some tests with 400 nodes and 400 links:
- V4.3.1, without images: the file loads for a second
- V5.0, without images: the file loads for a second
- V4.3.1, with 10 images: the file loads for 12 seconds
- V5.0, with 10 images: the file loads for 2 seconds
Each image from the last tests was assigned to 40 nodes. In this case, the speed in version 5 is better because the bytes of shared images are encoded and saved just once; whereas version 4 saves a separate copy for each node, and subsequently decodes 400 image copies when loading.
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Q: Can Diagram.LoadFromXml read XML strings created using previous version's XmlWriter class?
A: The old XML format is still supported for reading; actually you must use the LoadFromString method to load an XML string.
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Q: In v5, is there a performance difference between the LoadFromXml overload which takes a document vs. the one which takes a string?
A: The latter calls the former after creating an XmlDocument object from the string content.
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Q: Is it possible to convert a Diagram to a bitmap file.
A: Call the Diagram.CreateImage method and then the Image.Save method.
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Q: I am trying to create a custom drag&drop icon to show up when dragging the shape around on the screen. Is there a way to convert a flowChart shape into an image on the fly?
A: Create a graphics object using Graphics.FromImage. In order to draw a shape on the Graphics instance, create a temporary node, set its shape, and then call the ShapeNode.Draw method. A similar method is shown in the Flowcharter sample project where the icons in a list box represent Flowchart.NET shapes.
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Q: How can I export a diagram to emf file?
A: Use the following code.
using (FileStream stream = new FileStream(
@"C:\temp.wmf", FileMode.Create))
{
Graphics g = CreateGraphics();
IntPtr hDC = g.GetHdc();
Metafile metafile = new Metafile(stream, hDC);
g.ReleaseHdc(hDC);
g.Dispose(); IGraphics gMeta = new GdiGraphics(
Graphics.FromImage(metafile));
diagram.Draw(gMeta, new RenderOptions(),
diagram.Bounds, false);
gMeta.Dispose();
metafile.Dispose();
}
IGraphics and GdiGraphics are defined in the MindFusion.Drawing namespace.
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Q: Can I save to a file a selection of items.
A: Use the CopySelection and PasteSelection methods to copy the selected items to a second Diagram instance, and call the Diagram.SaveToFile method to save them to a file.
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Q: Can FlowChart.NET read my database schema and generate an ER diagram for it?
A: No. You should read the schema by ADO.NET and generate a diagram programmatically with the CreateTableNode and CreateDiagramLink methods.
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Q: I have an SQL-Table with some entries containing state and connection information in several columns. I already imported the nodes. Now I would like to organize the connections. Have you some hints which way I should choose to reach that?
A: To create the connections, assign the node ID from the database to the ShapeNode.Tag property while creating the nodes. Run a second loop over the link records, and for each related node ID you have for a node, call CreateDiagramLink(node, Diagram.FindNode (relatedID)). If you already use the Tags to store other information, save the relations in a Hashtable.
To arrange the diagram, use some of the layout algorithm classes, for example LayeredLayout.
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Diagramming
